DRAFT
5/14/2002
This document also available in Microsoft Word format

I.  Introduction
                    A.  Background

II.  Project Summary
                    A.  Project Schedule
                    B.  Watershed Overview
                    C.  EDNA Overview
                    D.  Stream Routing Overview

III.  Watershed Delineation
                    A.  Initiate Communication With Potential Cooperators
                    B.  EDNA Process
                                        1.  Definitions
                                        2.  Stage 1: Blind Pass Processing
                                        3.  Stage 2: Watershed Delineation and Review
                                        4.  Stage 3: Raster Editing
                                        5.  Certification

IV.  EDNA Stage 2 Tools
                    A.  Setup
                    B.  Watershed Delineation
                    C.  Reach Catchments
                    D.  Discrepancy Analysis

V.  NHD Edit Tool

                A.  Load Workspace
                                1.  Load NHD Workspace
                                2.  Load GNIS Workspace
                                3.  Show Tables
                B.  Flow Tools
                                1.  Flow QA/QC
                                2.  Adding flow records
                C.  Flipping Arcs
                D.  Naming Arcs
                E.  Metadata
                F.  Send to USGS

VI.  Stream Route and Water Body ID Process
                    A.  Stream Routing Tool (SRT)
                                        1.  Development Objectives
                                        2.  Functions of SRT
                    B.  Pre-SRT Screening of NHD Coverage
                                        1.  AML
                                        2.  Checking and Correcting Errors
                    C.  SRT Editing Procedures
                                        1.  Starting the SRT
                                        2.  Main Menu and its Buttons
                                        3.  STEP 1 – Setup/Edit/Flip Arcs
                                        4.  STEP 5 – Build Level 2 Routes
                                        5.  STEP 6 – Build Level 3 Routes
                                        6.  STEP 7 – Check Route System
                                        7.  STEP 8 – Add Stream Long/Lat
                                        8.  SRT Results
                    D.  Transfer of data to EDNA

VII. Metadata

The Hydrography Subcommittee’s Alaska Watershed and Stream Hydrography Enhanced Datasets (AWSHED) project has undertaken the tasks of preparing the NHD (fixing errors) for use in Alaska and developing a routed hydrography data set with standardized water body identifiers. It has also undertaken the task of delineating watersheds at the 5^th level and subwatersheds at the 6^th level. The AWSHED project will deliver the following products to Alaska.

The standardization of a waterbody identifier and stream routes is agreed to in a Memorandum of Agreement developed through the Alaska Geospatial Data Committee (AGDC) and signed by various state and federal agencies.

The hydrography subcommittee of the AGDC was formed in 1997 to explore possibilities to enhance a new data set for hydrography. The committee found that most information collected and stored about the riverine ecosystems in Alaska relate geographically to the entire river and/or to user defined reaches and sites on rivers. We found that existing formats, while suitable for cartography, provided no mechanism to link tabular information about rivers to a river, or to user defined reaches or sites on rivers in a true geographic information system (GIS).

There has been a clearly expressed need in Alaska for the delineation and standardization of watersheds at a finer scale than the 4^th level sub-basin currently existing in the Hydrologic Unit system, which is maintained by the Natural Resources Conservation Service (NRCS) and the USGS.

The watershed delineation process applied here is known as the Elevation Derivatives for National Application (EDNA) project and was developed by the USGS EROS Data Center. The establishment of stream routes and standard waterbody identifiers will be on the new line-data standard for hydrography called the National Hydrographic Data Set (NHD).

The stream routes, standard IDs and watershed derivatives such as catchments and seed points from the EDNA process will provide additional tools for watershed modeling and analysis. The NHD and the stream routes and LLIDs are complementary and fully compatible. A pilot project has been completed which tested and has proven the process of tying sets of tabular data to routed line data sets and has determined the costs for route processing and assigning the standard water body identifiers (LLIDs). The U.S. Geological Survey (USGS), Biological Research Division and the Bureau of Land Management (BLM) funded the pilot project.

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Work on the AWSHED project is dependent on the distribution of the NHD for Alaska by the USGS Rocky Mountain Mapping Center (RMMC). It is expected to take approximately one and a half to two years to complete the NHD. We will receive the data for watershed delineation and stream routing as a sub-basin coverage as it is completed. It is expected, as many as five to fifteen Sub-basins will become available per month. The actual hands-on processing work is expected to average about a week per Sub-basin if editing of the secondary channels is not included in the process. The secondary channels were not part of the USGS accuracy standards and therefore contain an exceptional number of flow direction and level errors. It could add two to five days of hands on processing to fix these errors. The project currently does not include the processing of secondary channels unless additional funding is available to increase the size of the team. The technical team currently includes two full-time members and one half-time member, which are available to work on data processing.

The AWSHED team and the RMMC have agreed to the following procedures for receiving and cleaning up the NHD.

Error fixing of the NHD will be accomplished using the NHDEdit tool, which was developed as an extension in ArcView (See section V for a detailed description).

Hydrologic Unit Codes (HUCs) are assigned for each hydrologic unit. For each hydrologic unit level two digits are added to the HUC. For example, Alaska is region 19, for sub-region 02 the HUC is 1902.

The national standard for the number of 5^th level watersheds is 5 to 15, with 8 to 15 sub-watersheds nested within one watershed. (Federal Standards for Delineation of Hydrologic Unit Boundaries)

Various Alaska specific adjustments to the national standards have been sanctioned because of the state’s large size and unique problems of varying topography (i.e. glaciers, braided streams). The Alaska Geographic Data Committee received clearance to adjust the following:

The process for the delineation of 5^th and 6^th level hydrologic units (watersheds and sub-watersheds) has been developed for Alaska. It will adhere to the Federal Standards for Delineation of Hydrologic Unit Boundaries and use the EDNA Stage 2 Tools (see section IV for a detailed description).

Cooperators will conduct a review of the products, and changes enacted before the results are submitted. The 5^th and 6^th level hydrologic units will be sent to the FGDC for evaluation. The Natural Resources Conservation Service (NRCS) ultimately will certify the dataset into the Watershed Boundary Dataset (WBD). The goals are a national seamless dataset and to provide more detailed delineation (subwatershed) and in digital format for local use that is consistent with other national seamless databases.

The primary products of the EDNA process will be 5^th and 6^th level hydrologic units and a revised elevation data set. Alaska, through the use of the EDNA Stage 2 tools will provide the revisions necessary for Stage 2 processing. EDNA Stage 3 processing will produce a vertically integrated, hydrologically conditioned and fully seamless dataset facilitating modeling and analysis. Vertical integration means that all the data (NHD, EDNA, WBD) will be in the same scale and same projection thereby eliminating the hassle

Hydrological conditioning is designed to determine flow direction, slope, gradient, watershed area, and flow accumulation at any place on the stream line feature. A seamless dataset allows data to be used in any size research area so each user can manipulate a manageable and desirable dataset. Existing DEMs will become the updated EDNA to correspond with the other datasets and to better illustrate "reality."

The National Hydrography Dataset (NHD) is a digital hydrographic dataset defining the nation’s streams and water bodies. The dataset includes unique identifiers for each individual stream section or reach, a flow network and the GNIS naming convention. The NHD is the basis for a routed stream coverage using Dynamic Segmentation in ARC/INFO to create routes representing rivers. This process is automated in the Stream Routing Tool (SRT) (See section VI for a detailed description).

Stream routes are uniquely identified using a longitude/latitude identifier (LLID) located at the mouth of each stream. The standardized LLID for these routes are assigned by the SRT when the routes are created. They can be used in relational databases as standard keys relating aquatic resources information to stream routes in the GIS. This allows the ability to query and display reaches and sites of a certain type in a GIS coverage. In Alaska the LLID waterbody identifiers serve as standardized common keys for the named and unnamed rivers, lakes, and other water sources that are represented graphically in a GIS.

Routing gives linear features measurements, allowing user’s to retrieve accurate location-specific information. Route number and measure coordinates define event attributes, or sites and reaches, along linear features. Examples of events that could be displayed through a simple query are water quality sample sites, stream gauges, habitat features such as fish barriers, navigable reaches, water quality discharge points, range of anadromy, spawning areas, bridges, culverts, white water classes, etc. etc.

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A letter of introduction (Appendix B) will be sent to establish contact points among the cooperators. Once contacts have been established a monthly update letter, outlining the hydrologic units where work will be in progress, will be sent out to request information that may aid in delineation of watershed boundaries. Any existing watershed boundaries that are within national standards will serve as a foundation for watershed demarcation. Requests may be made that are based on specific research areas, management responsibilities or any basis that warrants the aggregation of an area into a specific 5^th level hydrologic unit. Cooperators are requested to furnish the maps or digital data for their requests. These requests can be sent via FTP or e-mail.

Seed point – Pour point for a watershed or subwatershed

Catchment – The contributing drainage area for a reach

Pfafstetter system – A self-replicating numbering scheme based upon the topology of the drainage network and the size of the surface area drained which allows for identification numbers of the smallest subbasins extractable from a DEM.

                                        2.  Stage 1: Blind Pass Processing

Blind-pass processing generates flow direction, flow accumulation, synthetic stream lines and catchment development from the National Elevation Dataset (NED). Stage 1 processing employs the Pfafstetter coding scheme to derive catchments for each stream segment. Using the synthetic stream lines the analyst can aggregate the upstream catchment areas into one watershed. The furthest downstream point in each watershed is known as the seed point.

Upon receipt of the NHD the AWSHED project will route the coverage using the Stream Routing Tool. The routed coverage will be sent to the USGS for Stage 1b processing. Stage 1b will conflate the synthetic streams with the NHD. The synthetic 4^th level boundaries and the existing 250K 4^th level boundaries will be bundled for Stage 2 processing.

Delineation will proceed using the EDNA Stage Two Tools. The EROS Data Center has developed tools to facilitate 5^th and 6^th level delineation. The tools will automate delineation while assuring that the data will remain vertically integrated with the other national datasets. Tools have been created that identify problems between the synthetic data and the NHD and 250K hydrologic unit boundaries. Problem areas will be flagged for analysis and correction.

Completed 5th and 6^th level watersheds and all other relevant data will be sent to the cooperators for a review. The data will be sent via FTP, CD or in hard copy form to the cooperators, who will have two weeks to review (this can be modified on a case by case basis) the watershed and hydrography data. Cooperators will be asked to comment on concerns and provide feedback on possible adjustments to the data. The AWSHED team will attempt to reconcile and incorporate changes that are deemed necessary for compliance and feasible within the context of the project.  AWSHED will have a protocol in place for changes to assist the analyst in determining if a change is viable.

Concurrently the data will be sent to the USGS for Stage 3 processing.

The results from the Stage 2 delineation will be incorporated into the EDNA development process.  Drainage basin areas and synthetic streamline locations found to be in error at Stage 2 will be reanalyzed and, if necessary, the DEM will be reprocessed to ensure that the newly derived streamlines and basin boundaries are consistent with those developed in Stage 2.  Delineations derived in this fashion retain the desirable relationship between the DEM and the derivatives.  Following the completion of the Stage 3 boundaries, the entire suite of EDNA derivatives will be produced. These include the hydrologically correct DEM, flow directions, flow accumulations, slope, aspect and compound topographic index.

                                        5.  Certification

The 63360 DRGs are the final control for defining watersheds in State of Alaska as per the Federal Standards for Delineation of Hydrologic Unit Boundaries. AWSHED will do a final edit which will move 5^th and 6^th level HU boundaries to better conform to the DRG. Other data such as aerial photographs or DOQ can be used to help with severe problem areas.

The 5^th and 6^th level hydrologic units will then be sent to the Natural Resources Conservation Service (NRCS) for certification into the Watershed Boundary Dataset (WBD).

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Load the EDNA Stage 2 Tools extension into ArcView. Once loaded, a new window entitled "Stage 2 Editing Window" is created and several buttons and tools are added to the view button and tool bars. Figure 1 shows some of the added buttons and tools.

Figure 1. EDNA Stage 2 Tools extension interface.

Clicking on the button initializes the EDNA tool set. This button initializes several variables and displays the NED-H Stage 2 banner image.

After the initialization button has been clicked, the user can click on the button. After selecting the Stage 1 data directory, the data is automatically loaded to the "Stage 2 Editing Window" view.

Soon after the Stage 1 data has been loaded, a form is displayed. The purpose of this form is to collect tracking information, or general metadata, which will help identify the Stage 2 sub-basin and analyst. Figure 2 illustrates the form.

Figure 2. General metadata data entry form.

To help evaluate the sub-basin and determine how many watersheds and sub-watersheds will be needed, a button is provided, which automatically provides area information. Figure 3 shows an example of this window.

Figure 3. Sub-basin information window.

                    B.  Watershed Delineation

Once an overview of the HU has been accomplished (e.g. size and drainage pattern identification), watersheds and subwatersheds can be delineated. The tools facilitate the creation of EDNA derived delineations by two different methods.

In some cases, an analyst may have existing digital watershed data at their disposal. This data can be used to create EDNA "equivalent" delineations based on Stage 1 catchments. To create these equivalents, the analyst simply clicks on the button. The analyst is asked for an input coverage or shapefile and a field, which will be used as the defining parameter for catchment aggregation and subsequent merging. Once these steps are done the EDNA Stage 2 Tools automatically create a Watersheds or Sub-watersheds shapefile.

The second method for creating delineations is based on using the Pfafstetter coding associated with each "P_catchment". First, click on the button; a copy of the catchments is created. Once the copy is created, two views can be toggled using the button. Initially, the catchments are displayed with each catchment shown in a color based on the first three digits of the Pfafstetter code. This color scheme can be used as a visual tool for identifying possible topographic breaks that might make sense for boundaries. The second view simply shows all the catchments in a single color. The colors in this mode will update as new watersheds are identified.

                    C.  Reach Catchments

The next step is to identify the reach catchments, which will comprise watersheds and subwatersheds. The tool is used to select upstream catchments, from a selected downstream catchment, that comprise upstream watershed or subwatershed area. Figure 4 illustrates the selection and an information window that pops-up after the selection.

Figure 4

After a watershed has been identified using the aggregate tool, the user is asked to specify the number for the watershed. The numbering scheme should start at the furthest up-stream watershed and work its way down to the sub-basin’s pour point. For example Figure 4a, the user would enter a number of 01 (0101 for sub-watersheds) when prompted, which is then automatically attached to the 8-digit HUC number and placed in the attribute table for the shapefile. All reach catchments selected would then have a common 10-digit (or 12-digit for sub-watersheds) number, which is then used for merging the catchments in the next step. The user would continue to repeat this process until all watersheds or sub-watersheds were identified and labeled for the sub-basin.                                                                                                                                                       

When all watersheds or sub-watersheds have been identified and labeled, the ‘merge’ button is used to merge the catchments into watersheds. Figure 5 shows an example of a watershed shapefile created by merging aggregated catchments.

Figure 5                          

 Figure 6:

Data fields necessary for watershed and sub-watershed shapefiles attribution will be populated using the attribute  tool.  Click on the tool within a watershed; make sure that the watershed or sub-watershed shapefile is highlighted.  A dialog box with a drop down menu will appear as in Figure 6.  The drop down menu will contain any feature names available for the analyst to choose from to name a watershed.  Choose a name and click the  “OK” button.   

Figure 7    

Immediately upon clicking the “OK” button the Figure 7 dialog box will appear.  The analyst will verify the attribute information for the particular watershed or sub-watershed.  Note that every field must contain a character or the program will not allow the user to continue.  All fields should be filled in with information specified by the Federal Standards for Delineation of Hydrologic Unit Boundaries.                   

                    D.  Discrepancy Analysis

During the discrepancy analysis, the analyst will determine if the default seed point location is accurate or needs to be corrected. Clicking on the button creates Watershed_seeds and Sub-watershed_seeds shapefiles. The analyst edits seed points using the button. Pop-up windows ask the analyst if this is correct then redisplays the points on the layer as "fixed," "temp" or "unknown" as shown in Figure 8. Once the layer shows that all points are "fixed" or "temp" then every seed point has been reviewed and the editing is complete.

Figure 8

After watershed, subwatershed delineation, attributing, seed creation and editing, the next step involves the identification of discrepancies between synthetic data and existing data sources such as the 250k HUC and NHD streams. This process is initiated by clicking on the button. Once activated, four shapefiles identifying possible discrepancies are created. The shapefiles are shown in Figure 9, include those representing NHD and synthetic intersections with the 250k HUC boundary, discrepancies between the synthetic and NHD streams, and NHD intersections with the aggregated Sub-watersheds shapefile.

Figure 9

On a watershed-by-watershed basis, the analyst examines the data layers for possible discrepancies. The layers created above can be reviewed iteratively by activating the button. Once activated, the analyst clicks anywhere in the view to start the review process. After optionally entering a record number to start with, the user simply clicks in the view to review each of the identified discrepancies.  

If a discrepancy is deemed significant enough to flag; the (line flag) and (polygon flag) buttons can be used to create and attribute flags with information that will be used in Stage 3 processing (i.e. creating a hydrologically conditioned DEM). The Line Flag and Polygon Flag shapefiles (Figure 10) are created automatically when the button is depressed. The analyst uses the four discrepancy shapefiles provided or any ancillary data sources, such as DRG and DOQ data, to identify and describe any discrepancies.

Figure 10

Figure 11 and Figure 12 show examples of the dialog for attributing the line and polygon flag shapefiles.

Figure 11. Example of the line flag-attributing dialog

Figure 12. Example of the polygon flag-attributing dialog.

Once line and polygon shapefiles have been created to identify discrepancies, all Stage 2 data can be checked for completeness by clicking on the button. This function checks the attributes of the created Stage 2 shapefiles to ensure that all required information is present.

Finally, the Stage 2 data is renamed and shown in a new view so the analyst can review it a final time before sending it to Stage 3 processing. This is done automatically by clicking on the button.

Two additional buttons are included with the extension. The button is used to clear variables (e.g. count variables) and the button is used to create a new general metadata table.

The discussion above is meant to provide a general overview the developed ArcView tools. Refer to the provided help files for more detailed discussion of the individual steps in use of EDNA Stage 2 tools.

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V.  NHD Edit Tool

The NHD Edit tools needed are two ArcView extensions, NHD Edit and NHD Load/Unload Workspace.  To turn on these extensions in ArcView, choose Extensions under the File menu.  In the list of extensions place a checkmark next to NHD Edit and NHD Load/Unload Workspace.  When this is done a new menu called NHD_Tools and several new buttons will appear on the toolbar of a view.  This document will describe some of the menu options and buttons.

                    A.  Load Workspace

                                        1.  Load NHD Workspace           

The first step in using the NHD tools is to load the workspace containing the NHD data.  This workspace will usually be a folder named the HUC for the sub-basin of interest (i.e. 19020503).  An openme.txt file should be contained within the HUC folder.  In ArcView, select Load NHD Workspace from the NHD Tools menu.

NHD Tools à Load NHD Workspace

This will open a file selection dialogue (Figure 13) where you can browse to the HUC folder and select the openme.txt file.

Figure 13 - Select Openme.txt File

Using the provided 'NHD Load/Unload Workspace General Load Options' dialog (Figure 14), select the general type of load to perform.  For convenience, several 'quick-load' options have been provided, as well as a custom load option.

Figure 14 - Load Workspace

All Themes, Tables, and Links – will automatically load all the themes, tables, and links contained in the NHD Workspace.  Selecting this option directly loads the workspace.  No other dialogs will appear.  Please note, when this checkbox is checked, no other checkboxes are enabled. 

Custom – will initiate a custom load.  In this situation, two additional dialogs will appear to allow the choice of themes, tables, and links to be loaded.
        NHD Themes and Tables dialog – check the themes and tables that will be opened for this NHD workspace.
        NHD Links dialog – check the table links to be established for this NHD workspace.   Only the links that are possible based on the theme and table choices will be enabled.  This step will not be necessary if no links are possible due to the nature of the themes and tables selected from the NHD Themes and Tables dialog.

One or more of –
        Linear and Waterbody Reach Themes, Tables, and Links
        Network Themes, Tables, and Links
        Waterbody Themes, Tables, and Links
        DUU Boundaries
Making a selection from these choices directly loads the workspace.  No other dialogs will appear. 

                                        2.  Load GNIS Workspace

Select Load GNIS Workspace from the NHD Tools menu and a file selection dialogue (Figure 15) will appear. 

NHD Tools à Load GNIS Workspace

Figure 15 - Open file

Browse to the GNIS folder, which will be named gnis-rregionnumber-20000512 (i.e. gnis-r19-20000512).  Select the openme.txt file and the GNIS Workspace will be automatically loaded and clipped to the current NHD Workspace.

After loading the NHD and GNIS Workspaces the view should be similar to Figure 16.

Figure 16 - NHD View

                                        3.  Show Tables

Selecting the Show NHD Tables option from the NHD Tools menu allows users to view feature tables for the themes that have been loaded using the Load NHD Workspace menu choice.  In order to manage the screen real estate, the NHD feature themes have been divided into four groups:  Reaches, Network, Waterbodies, and Landmarks.  Only one group of tables can be displayed at a time.

            NHD Tools à Show NHD Tables

Figure 17 - Show Tables

After selecting the Show NHD Tables menu option, the Show NHD Tables dialog appears (Figure 17).  Users can choose to view Reach Tables, Network Tables, Waterbody Tables, or Landmark Tables by clicking on the appropriate radio button.  Only one choice can be selected.  If you have chosen to  Show NHD Tables and more than one NHD Workspace has been loaded, a list of loaded workspaces will appear before the Show NHD Tables dialog.  You may select one workspace from this list.  The radio buttons within the Show NHD Tables dialog will be enabled only if the appropriate tables were opened when the NHD Workspace was loaded.  For example, if the network themes and tables were not loaded, then the network tables radio button will not be enabled.

Figure 18 shows the tables loaded using the Reach Tables option.  The view and all tables within ArcView are automatically tiled for optimum viewing.

Figure 18 - Reach Tables

                    B.  Flow Tools

                                        1.  Flow QA/QC

 The  tool will cause an executable to be initiated.  A workspace specific window containing flow errors will be opened when the Flow QA/QC is finished. If more than one NHD Workspace has been loaded into the current view, a list of workspaces will appear immediately after the Flow QA/QC button is pressed.   Multiple selections may be performed by left-clicking on each desired workspace. If only one NHD workspace has been loaded, a list will not appear and the Flow QA/QC process will proceed for that NHD workspace immediately upon clicking the Flow QA/QC button.

The Flow QA/QC process opens a table document window in your project named Workspace Name - Flow Errors (i.e. 19020503 – Flow Errors, Figure 19).  There will be multiple flow errors table windows if the Flow QA/QC was performed on multiple workspaces.

Figure 19 - Flow Errors

Each record in the Flow Errors table represents a potential flow problem.   Activate the Flow Errors table and use the Next/Previous  buttons to zoom to each error.  The error types are identified by a code in the comment field of the flow errors table.  The NHD Edit Help, under the Help menu in ArcView, identifies the codes, provides a description of each error, and provides possible solutions.

                                        2.  Adding flow records

The flow tools include: Start Flow Record, Inflowing Flow Record, Outgoing Flow Record, Terminal Flow Record, and Coastline Flow Record.  To use any of the tools, activate the desired tool and then select one or two reaches from editable workspaces, depending on the specific tool.  After the selections, the Flow Record dialog (Figure 20) appears.  The dialog reflects the reaches selected by the mouse clicks and the direction necessary based on the active tool.  The 'Sequence' field is available for editing whenever the users is adding something other than a start or terminal flow record. 

Figure 20 - Flow Record

Start Flow Record – Point and click on a start reach.  The reach will be highlighted and the Flow Record dialog will be displayed.  (Com Id 1 = 0, Com Id 2 = selected reach, Dir = 712, and Sequence = 0).  From the Flow Record dialog, you can choose whether or not to add the flow record.  Sequence cannot be edited for start flow records.

Inflowing Flow Record – Point and click on one reach (wait for it to get highlighted), then point and click on another reach (wait for it to get highlighted).  Reach 1 ‘Flows To’ Reach 2.  Both reaches will be highlighted and the Flow Record dialog will be displayed.    (Com Id 1 = Reach 1, Com Id 2 = Reach 2, Dir = 709, and Sequence = 0).  You can then edit the sequence and choose whether or not to add the flow record.

Outgoing Flow Record – Point and click on one reach (wait for it to get highlighted), then point and click on another reach (wait for it to get highlighted).  Reach 1 ‘Flows From’ Reach 2.  Both reaches will be highlighted and the Flow Record dialog will be displayed.  (Com Id 1 = Reach 1, Com Id 2 = Reach 2, Dir = 710, and Sequence = 0).  You can then edit the sequence and choose whether or not to add the flow record.  In this case, the sequence MUST be something other than 0.

Terminal Flow Record – Point and click on a terminal reach.  The reach will be highlighted and the Flow Record dialog will be displayed.  (Com Id 1 = selected reach, Com Id 2 = 0, Dir = 713, and Sequence = 0).  From the Flow Record dialog, you can choose whether or not to add the flow record.  Sequence cannot be edited for terminal flow records.

Coastline Flow Record – Point and click on one reach (wait for it to get highlighted), then point and click on another reach (wait for it to get highlighted).  Reach 1 ‘Flows To’ Reach 2.  Both reaches will be highlighted and the Flow Record dialog will be displayed.    (Com Id 1 = Reach 1, Com Id 2 = Reach 2, Dir = 714, and Sequence = 0).  You can then edit the sequence and choose whether or not to add the flow record.

If the user enters a sequence greater than 0 and then presses 'OK' to actually add the record, a prompt appears asking if you would like to update the sequences for all related sequenced flow.  Pressing 'Yes' causes all flow records where com_id_2 equals com_id_2 of the new flow record to be analyzed.  Wherever the sequence in the existing relationship is equal to or greater than the sequence in the new flow record, the old sequence value is incremented by 1.  Pressing 'No' means that sequences for related flow records are not automatically updated.   The new flow record is still added.

                    C.  Flipping Arcs

The Flip Coordinates tool  allows users to mark reaches or drains so that the coordinates, or internal flow direction, will be flipped to match flow direction when the updated workspace is reloaded into the central USGS location.  After selecting this tool, activate a reach or drain theme in an editable workspace, select a reach or drain, and wait for the reach or drain to be highlighted.  The status table should be updated with an ‘F’ transaction.  No visible difference will exist for the reach or drain.  Actual spatial data will not change at this time.

                    D.  Naming Arcs

To use the Name Application tool , activate the tool from the toolbar (i.e. click on it).  This will open a Current GNIS Name box containing the GNIS ID, name and feature type of the currently selected GNIS entry (Figure 21).  If no name is displayed or to change the displayed entry, you should make the GNIS theme active and use the ArcView selection tool to select the desired GNIS line or point.  The desired name may also be selected from the GNIS table.  When the GNIS table is open the Next/Previous buttons may be used to automatically zoom to the desired record.

Figure 21 - Name Tool

Once the tool is selected, apply names to NHD Features by activating the appropriate NHD feature theme and selecting the desired feature.  Each click on an NHD feature with the Name Application tool active, is an attempt to apply the displayed GNIS name to that NHD feature.  Before applying the name NHDEdit confirms that the NHD feature is allowed to have a name and that the feature type of the NHD feature and the GNIS feature are compatible.  If not, an error message is displayed and the name is not applied to the NHD feature.  Applying a name replaces whatever name may have been there in the first place.  Therefore, you do not have to remove an inaccurate name before applying a new name.

Incorrect names may be removed from a feature by using the Remove Name tool .  Once the tool is selected, remove names from NHD Features by activating the appropriate NHD feature theme and selecting the desired feature.  Each click on an NHD feature with the Name Removal tool active, is an attempt to remove the name from that NHD feature. 

                    E.  Metadata

The NHD tools allow users to edit associated metadata for the particular set of NHD updates they are working on.  Select Edit Metadata from the NHD Tools menu.  

NHD Tools à Edit Metadata

This option is available when there is at least one editable workspace in the current view.  If more than one editable NHD Workspace has been loaded a list of editable, loaded workspaces will appear.  Multiple selections may be performed by left-clicking on each desired workspace.   If only one editable NHD workspace has been loaded, a list will not appear and the editing metadata process will proceed for that NHD workspace immediately upon selecting the Edit Metadata menu option.

The Edit Metadata process opens a script document window named Workspace Name  - Metadata (i.e. 19020503 – Metadata, Figure 22) in your project.   This script document window can be edited similar to editing a text file.  If there is not already a Workspace Name - Metadata window in the current project for a selected workspace, one will be created.  It will either be a new metadata window, or it will contain the contents of a previously existing cu.upd file.

Figure 22 - Metadata

For new metadata windows, users will be prompted to add a GNIS Source Used Citation.  Responding 'No' to the prompt will cause the Workspace Name - Metadata window to be active, allowing users to edit the Process Description for the metadata.  Responding  'Yes' to the prompt will cause a file selection dialog to appear asking for the GNIS openme.txt file.  Once the openme.txt file is selected, the following pre-formatted metadata information will be inserted into your script window:

Source Citation Abbreviation: Gnis-r19-20000512
Originator: U.S. Geological Survey
Title: Geographic Names Information System Oracle Database
Publication Date: unpublished material
Beginning Date: Not Applicable
Ending Date: Not Applicable
Source Contribution: names for reaches, aerial water bodies, and landmark features
Source Scale Denominator: Not Applicable
Type of Source Media: online
Calendar Date: 20000512
Source Currentness Reference: custom extract from the GNIS databases

If there is already a Workspace Name - Metadata window or file for the in the current project for the selected workspace, the window will be re-opened and the user can enhance existing metadata.   The user will be given the opportunity to add a GNIS Source Used each time the metadata window is reopened.

If multiple workspaces were selected from the list of editable workspaces, metadata editing windows will be opened for each selected workspace.  The Add GNIS Source Used prompt will appear each time a metadata window is opened.  Control will return to the user in the metadata window of the last workspace processed.  All of the metadata windows will remain open.  Please remember, closing a window does not remove the window from the project OR save the information in the window.  To save edits select Save Metadata from the NHD Tools menu.

NHD Tools à Save Metadata

The Save Metadata menu option is available whenever the current project contains a metadata document for at least one editable workspace in the current view.  If more than one metadata window has been created for editable NHD Workspaces contained in the current view, a list identifying each workspace will appear.   Multiple selections may be performed.  If only one metadata window has been created for an editable workspace in the current view, a list will not appear and the Save Metadata process will proceed for that NHD workspace immediately upon selecting the Save Metadata menu option.  The Save Metadata process consists of saving the information in the metadata window to a text file in the workspace's \metadata directory named cu.upd and removing the metadata window from the current project.

                    F.  Send to USGS

After all edits have been finished and metadata has been edited, select the Send Updates to USGS option from the NHD Tools menu.

            NHD Tools à Send Updates to USGS

This will automatically bundle the NHD Workspace into a tarred and gzipped file to be sent to USGS.  The file will be named HUC_updates_datebundled.tgz (i.e. 19020503_updates_20011022.tgz).  The file can then be sent to USGS for further editing to be accomplished.

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The SRT is an automated tool for routing stream coverages. The need to automate the process of building routes on hydrographic data using dynamic segmentation has been identified by several federal and state agencies including US Forest Service, Bureau of Land Management, Washington State Department of Wildlife, Oregon Department of Fish and Wildlife, and others. The SRT application was developed to meet the Interagency Resource Information Coordinating Council (IRICC) standard stream identification approach. The IRICC stream identification approach is based on uniquely identifying individual route systems on a stream network. Each unique identifier is based on the longitude and latitude of the mouth of the stream. Routing gives linear features measurements, allowing user’s to retrieve accurate location-specific information. It builds a route system on the input data set that can then be dynamically segmented.

Dynamic segmentation allows assigning events to linear data without segmenting the data for each attribute type. Events are attributes that occur along linear features. Event position is defined in terms of route and measure coordinates. This allows changing the attribute’s allocation without modifying the basic structure of the data. The routes can be constructed using a predetermined attribute that groups together a set of arcs, or by selecting arcs by user's choice (known as steering). The route attribute table (*.rat{routesystem}) and section table (*.sec{routesystem}) permit storing route attributes and section measure of the routesystem.

SRT is the application for building routes following IRICC standards on a hydrography layer. It has been developed to run within the ArcINFO environment using its macro language (AML) and menus for ease of use. It can be used for data on any scale. Alaska will be using data at a scale of 1:63,360. The SRT can only be run on a UNIX platform. The UNIX platform can be accessed through an X-term on an NT machine with Xoftware.

For routing a 63360 NHD coverage, SRT is designed to perform the following functions:

1) To make a copy of the selected coverage and process the copy by adding the necessary items and flipping arcs, if required. The working coverage is created by adding an "_ll" extension to the selected input hydrography coverage.

2) To build routes for the arcs (streams) using an attribute.

3) To assign routes to streams not routed by attribute based on longest length through the network of remaining arcs.

4) To allow correction of erroneous routes.

5) To add LongLat-ID (LLID) following the IRICC standards to all routed streams.

In addition to route building tools, SRT provides some simple ARC editing tools, which can be used for improving the quality of the coverage.

The pre-SRT screening of the data will be to check and edit the levels and naming conventions on the streams. Any data manipulation should be accomplished in ArcINFO to maintain the integrity of the features. An AML called masternhd.aml has been written to convert the NHD data into a useable format. Masternhd.aml reprojects the coverage into Albers projection, removes the polygons and places them in a separate coverage called regions, and relates the tables to add the Level and Rivname fields to the nhdalb.aat (arc attribute table). The masternhd.aml also redefines the Rivname field as Name2 to be compatible with the Name field in the SRT. The coverage is renamed to nhdalb when it is reprojected. All new coverages are saved in the same folder.

To run masternhd.aml open up ArcINFO. Enter into the directory where the nhd coverage exists, this will generally be named the eight-digit HUC, i.e. 19020503.

               Arc: &amlpath /data/nhd/amls                           *this sets the path so ArcINFO can find the aml
                                                                                                    *only necessary if no permanent amlpath is set
               Arc: &r masternhd nhd                                           * runs the aml

The data can be checked for errors by using the following commands in Arcedit.

                Arcedit: display 9999
        Arcedit: ec nhdalb
        Arcedit: de arc
        Arcedit: draw
        Arcedit: ef arc
        Arcedit: sel name2 = ‘stream name ’;ds            *this shows all arcs with that name
               Stream name is case sensitive. All named streams can be selected simultaneously by typing: sel name2 > "a";ds

To correct obvious errors:

               Arcedit: sel path                                                       *can also use "sel one" or "sel many" to choose arcs
               Choose the beginning and ending points of the stream/river you would like to edit
               Arcedit: calc name2 = ‘stream name ’

To run the SRT, be in the directory containing the nhdalb coverage and open ArcINFO:

               Arc: &amlpath /data/nhd/amls/srt                   *if amlpath is not already set
               Arc: &r srt                                                             *to run srt

This brings up a pull-down menu (Figure 23), which lists the available coverages in the present working directory. Always select the original name of your stream coverage. SRT’s working copies of your coverage (bearing the "_ll*" extensions) will not be listed.

Figure 23

SRT will always look to see if a coverage exists with the “_ll” extension based on the input name the user selects.  Initially the application creates a copy of the selected coverage with an "_ll" extension and works on the copy keeping the original coverage unchanged.  The input coverage name should be 8 characters or less.  The 8-character limitation is designed so SRT can add extensions to the name at various steps in the application.  The main menu will automatically pop up (Figure 24). 

Figure 24

                                        2.  Main Menu and its Buttons

The eight buttons on this main menu of SRT (Figure 24) allow you to build and edit a route system on the selected coverage.  You can stop and start the application. However, you need to remember which step you last finished and proceed from there on.  After each step is complete the application will make a backup copy of the working coverage with the step number attached (e.g. nhdalb_ll5).  This allows the user to return to the previous step if a problem occurs in the application.  For example, if an error occurs in Step 6, exit the SRT.  In ArcINFO: 

        Arc: kill nhdalb_ll all
                    Killed nhdalb_ll with the ALL option
             Arc: rename nhdalb_ll5 nhdalb_ll
           Arc: &r srt
               Select nhdalb from the pull-down menu (Figure 23).

When the main menu pops up, click on Step 6 and continue from there.

                                        3.  STEP 1 - Setup/Edit/Flip Arcs

On the selection of this button, SRT checks if there is a work coverage with extension "_ll" for the selected coverage in the working directory.  If the working coverage doesn’t exist, SRT will create the new coverage using the selected coverage name and “_ll” extension.  The application will then ask if the user would like to edit the coverage or move on (Figure 25).  It’s recommended that the edit environment is started so arc direction and any possible node errors can be identified.

Figure 25

If the work coverage exists, the system informs you of the presence of this coverage and provides you with the following edit options (Figure 26).

Figure 26:

1  Exit Routine -- Returns you to the main menu to continue to the next step.

 2  Edit Work Layer -- It allows you to edit the “_ll” coverage using the editor.

 3  Kill/Replace Work Layer -- It kills the old work coverage with "_ll" extension and starts the process afresh.

In either of the above menus (Figure 25 and Figure 26), you have access to the "Editing Hydro" menu (Figure 27) with some limited editing capabilities.  It is recommended that most of the editing to the initial coverage take place before running SRT.  This editor is more of a checking tool with the ability to make manual edits to the working coverage.  It should be noted that edits to the working coverage have no effect on the original coverage selected when SRT is started.  The user is always editing the working coverage with the “_ll” extension.

The SRT application will inform the user if polygons have been found on the coverage.  Because you are building a route system on all arcs in the working coverage the user will need to remove all polygons.  In most cases this means building centerlines through lakes and double line river systems.  The major editing for centerlines should have been done in the coverage preparation before SRT is run, however, the application will still check and show you label points for any polygons still present in the edit environment.  Don’t leave any closed polygons on the working coverage.  Polygons later in the SRT process will cause errors!  The application will remove label points.

The edit environment is pre-set in the edithydro.aml with colors being assigned through draw symbol item (dsi).  The following descriptions of each button on the “Edit Hydro” menu (Figure 27) will give the user a general working knowledge of editing options, but for more detailed ArcEdit capabilities, please see ArcINFO’s user help.

  Figure 27:

Select One -- Allows you to select a single arc, which can be moved, deleted, or modified.
Select Many -- Allows you to select many arcs, which can be moved, deleted, or modified.
Select Path -- Allows you to select arcs using the path option where the user is asked to click at the starting and ending points of the path. No arcs are selected if the selected path is not continuous. This option of selecting arcs is useful for flipping arrow direction for a set of connected arcs.
Unselect All -- Unselects all selected arcs.

Set Edit Distance -- Allows you to set the search distance for selecting features by pointing on the screen and adjusting the search tolerance distance.
Move Arc -- Allows you to move an arc from one location to another.
Delete Arc(s) -- Deletes one or more arcs. You need to select the arcs using one of the arc selection buttons (Select One, Select Many, or Select Path) prior to using this button. 
Add Arc(s) -- Allows you to add one or more arc(s) to the coverage. The selection of this button provides you with the "ADD" menu of ARCEDIT.

View Arc Directions -- Displays arcs with arrows indicating the direction of arcs. As included in the IRICC standards, all arcs should be pointing downstream in the direction of flow and all route indices should be increasing in the direction opposite to the direction of flow.
Flip Selected Arc(s) -- This button only flips arc direction on the selected arcs. This button does not synchronize arrow direction with other arcs, rather it uses the ARCEDIT "FLIP" command to reverse the direction of the selected arcs.
Flips Arcs towards Outlets - Prompts you to “Point to outlet node(s).”  Click on the node(s) with the graphics cursor.  Enter a 9 (Ctrl-right mouse button) when done.  All arcs connected directly or indirectly to this node(s) are then flipped to point downstream towards it.  Arcs that were already pointed in the correct direction are displayed in green.  Arcs that were flipped are displayed in blue.  And arcs that were not connected remain in black/white.

Select All -- Selects all arcs on the coverage.  This is used in conjunction with the following “Remove Pseudo Nodes”.
Remove Pseudo Nodes -- Removes pseudo nodes of the selected set.  If the “Select All” option has be used to create the selected set of arcs all pseudo nodes on the coverage will be removed.  By removing unwanted pseudo nodes the SRT application will run faster and smoother.  Remove as many as possible, but remember data loss may be a factor as to how many pseudo nodes are removed.

Redraw Cover -- Redraws the coverage showing the most recent selections and updates.
Node Errors -- Displays node errors such as dangles or pseudo nodes.
To Keyboard --Transfers the control to command line prompt of ARCEDIT thus allowing you to carry out ARCEDIT functions using the keyboard.  The menu commands are de-activated during the usage of keyboard. You can re-activate the menu by entering "&return" on the command line.

Save Work -- Saves the current work session without exiting the program.
Save & Exit -- Saves and exits the current work session. 

Exit -- Exits the menu. However, the system warns you about the unsaved changes, and asks if you would like to save the changes prior to exiting. If not saved all changes will be lost.
Help -- Gives the user limited online help.

STEP 2, STEP 3 and STEP 4 are not applicable to Alaska.

                                        4.  STEP 5 - Build Level 2 Routes

This step puts the user into a route assign mode where you have the control in selecting arcs for route assignment under ArcEdit (Figure 28). All the arcs with assigned routes are displayed in a color (yellow) different than the arcs without route-id assignment (blue).  You can then select paths to assign additional routes where needed.  Once a route is assigned to a river or stream, it is redrawn in a different color (orange).  This process of route assignment is called "steering" and is fairly labor intensive. The user can assign as many or as few as they require.  However, it is advisable to assign routes using this approach to all streams that do not follow the longest length through the network of remaining arcs.  Otherwise the routes created during Level 3 Route Building (Step 6) will not follow these streams.

The route menu displays the last route number and the current route number (Figure 28).  These numbers are updated each time a new route is added to the coverage.  The buttons on this menu perform the following functions:

Figure 28: 

Next Route -- calls the route-building menu (Figure 29) which allows you to select a set of arcs for assigning route-id. This menu provides several options for selecting and building routes. Arcs to be grouped into a route can be selected using one or more arc selection buttons such as Select One, Select Many, Select Path, Unselect One, Unselect Many, and Unselect Path.  The "9" key completes the selection. The route-building process is completed by clicking on the button Build Route, which assigns the route number to the selected arcs and displays the new route (orange).  A single arc stream doesn’t need to be assigned a route using this approach. They will be assigned route-IDs during Build Level 3 Routes.  If only one arc is selected, the SRT will not build a route.

To Keyboard -- Puts the user at the ArcEdit command line.  It’s very important that the user doesn’t edit topology at this point.  The application is assuming that all topological editing has already taken place in Step 1.

Build routes from AAT item -- This button allows the user to select an item from the arc attribute table, which can be used to build routes.  Routes can be built based on the GNIS naming convention by selecting the Name item. 

Edit Route -- This button is used whenever you want to modify an existing route. It allows you to change the Route Number and/or Stream Name. This activates another form menu (Figure 30). This menu is similar to the one described above and allows you to select one or more arcs and to select, transfer or erase Route Number and Stream Name using the appropriate buttons.  The following is a brief explanation of some of the unique buttons to this menu follows:

 Figure 30:
 

Select Number -- Sends a selected route number to a temporary variable for transfer to additional arcs. Pressing this button prompts you to select an arc with the number to be transferred. The number can be viewed using "List Name/Num" button.
Transfer Number -- Completes the action of transferring a Route Number from one arc to one or more other arcs.
Erase Number -- Erases the Route Number from selected arcs.

Select Name -- Similar to the "Select Number" button, this button sends Stream Name and Route Number to temporary variables for transfer to additional arcs. The information collected (Name and Route Number) can be viewed using "List Name/Num" button.
Transfer Name -- Completes the action of transferring Stream Name and Route Number from one arc to one or often more arcs.
Erase Name -- Erases name from the selected arcs.

List Name/Num -- Lists the Stream Name and Route Number of the selected arc(s).
Save Routes -- Saves current work. 

Done -- Returns to the previous menu (Level 2 Route Builder Menu, Figure 28)

                                        5.  STEP 6 - Build Level 3 Routes  

This step assigns routes to all remaining arcs that were not given a route number in the steering process.  The routes are based on longest length through a network.  Grouping connected arcs and then finding the longest path through the group do this.  When complete, the final route system streams is created.  The streams route system is indexed based on a conversion of length in the nhdalb_ll.aat to kilometers following IRICC standards.  All arcs on the working coverage should be assigned to the streams route system and indexed.

                                        6.  STEP 7 - Check Route System

This step allows the user to check for errors on the Streams route system, which was created in the previous step.  The SRT application performs a simple check of the route system by examining the “f-pos” in the section table (nhdalb_ll.secstreams).  If the application finds an f-pos equal to zero the application flags it as an error and give the user a chance to modify the possible error.  The f-pos equal to zero is used because each route created is “flipped” to run from the mouth upstream to the headwaters.  If the route is properly flipped the f-pos should equal 100.  The index thus runs upstream with index zero beginning at the mouth.  Remember that this is only a simple check and doesn’t tell you anything about route location on the original arcs.  The route system may need route location editing later, which the SRT application doesn’t do.

Once selected this step puts the user into one of two menu systems based on the selection of f-pos equal to zero.  If the application finds no records selected it notifies the user that the route system was successfully constructed, as far as it can tell, but notifies the user that it may not have found all possible errors (Figure 31).

Figure 31

If errors are found, the “route edit menu” is called (Figure 32).  The problem routes are displayed, one at a time.  When you edit the coverage and save it, a variable is set which tells the application that the Streams route system needs to be reconstructed upon exit.  This reconstruction of the route system uses the edited route.no item in the nhdalb_ll.aat.  Because the route system needs to be rebuilt it may take some time depending on the size of the working coverage.   If the application continues to find errors, it will again place you in the editing part of the application.  If you don’t want to continue editing and want to move on without rebuilding the route system, simply exit without saving. This will cause the rebuilding variable not to be set and the application will continue to Step 8.

The following is a general description of the route editing menu functions (Figure 32).  It is important to remember that you are actually editing items in the nhdalb_ll.aat and not the routes themselves.  The user can always move past this step to Step 8 and edit the final routes later with a different tool or manually using ArcEdit commands. 

  Figure 32:

Select One -- Selects one arc.
Select Many -- Selects many arcs.
Select Path -- Selects a path of arcs.
To Keyboard -- Puts user on command line (note: use "&return" to get back).

List Number -- List route.no and name item from select set of arcs.
Redraw Route -- Selects route.no equal "Current Route" and redisplays.
Zoom Select -- Zooms to the select set of arcs.
Zoom Default -- Zooms back to the original extent.

Select Number -- Sends a selected route number to a temporary variable for transfer to additional arcs.
Enter Number -- Calculates the selected set of arcs route.no equal to the value of the variable selected using the "Select Number" button above.
Erase Number -- Erases the route.no item in the selected set of arcs.

Select Name -- Sends a selected name to a temporary variable for transfer to additional arcs.
Transfer Name -- Transfers the name selected from "Select Name" to the selected set of arcs.
Erase Name -- Erases name item in the selected set of arcs.

Flip Arcs -- Reverses direction of select set of arcs.
Build Route -- Calculates the selected set of arcs equal to the "Next Route" displayed on the top of the menu.
Move to Next -- Move to next route. If there are no additional routes to be selected the save menu will be displayed.

Save -- Save without exiting
Exit -- Exits menu and asks to keep or discard changes if made

                                        7.  STEP 8 - Add Stream Long/Lat

This button calculates and assigns LLID (Longitude/Latitude Identifier) using the IRICC standards to all routes.  The LLID item in the nhdalb_ll.rat, nhdalb_ll.sec, and nhdalb_ll.aat is populated with the calculated values of LLID for each route/stream.  (NOTE: Retention of the llid, name, and kilo_length items in the nhdalb_ll.aat and nhdalb_ll.sec files is optional; you will be prompted.)  The LLID is based upon the coordinate values (Longitude and Latitude) of the mouth of the stream.  The LLID is 13 characters long, with 7 for decimal degrees of longitude and 6 for decimal degree of latitude. Decimal points are implied. This system of identifying routes (LLID) provides flexibility across agencies, geographic areas and also reduces the chance of duplicate IDs.

Upon the successful completion of the LLID assignment to all routes, the system presents a message indicating the completion of routing on the selected coverage.

The SRT application produces a route system on the working coverage called streams.  Each arc on the working coverage should have a route assigned with a unique longitude and latitude identifier (llid) assigned.  The route system has been indexed using kilometers as the index value (Kilo_length).  The following are items and their explanation, which are created by SRT in different INFO files of the working coverage.  The items will be added to the nhdalb_ll.ratstreams table and can be added to the nhdalb_ll.aat  and nhdalb_ll.secstreams tables.

Name – stream names from GNIS naming convention
LLID – IRICC Unique Stream ID
Kilo_Length – ARC Length converted to Kilometers

When the SRT has finished the final coverage will be nhdalb_ll; the feature class with the routed streams will be route.streams.  There will be other coverages in the directory (nhdalb_ll1, nhdalb_ll5, nhdalb_ll6, etc.) because the SRT makes a backup coverage after each step; these coverages can be deleted.

The data that needs to be sent to EDNA is the whole nhdalb_ll coverage. The coverage that will be sent must be exported and gzipped.

In the UNIX terminal window:

        $:arc
        Arc: export cover nhdalb_ll nhdalb_ll

        Arc: gzip -f nhdalb_ll.e00