nawqa_glac1 is a polygon coverage of glaciers in the Cook Inlet National Water-
Quality Assessment (NAWQA) study unit. The Cook Inlet NAWQA is located in
southcentral Alaska and the coverage was created from 1:2,000,000 digital
line graphs (DLGs).
The purpose of nawqa_glac1 is to give a general overview of the amount of glaciers present in the Cook Inlet Basin. Because glaciers play an important part in the hydrology of rivers and streams, their absence or presence will be a critical factor in the selection of water-quality sampling sites for the Cook Inlet NAWQA.
Procedures_Used:
The glacier coverage was created by USGS and Alaska Division of Natural Resources (ADNR) personnel using the USGS 1:2,000,000 digital line graphs (DLG) and techniques described by Domaratz and others (1982). Polygons representing glaciers were assigned a value of 40 to the item MAJ in the polygon attribute table. The drainage basin boundaries of the Cook Inlet Basin, developed from 1:250,000 quadrangle maps, were used as the boundaries of the coverage.
Revisions:
No revisions have been done.
Reviews_Applied_to_Data:
Coverage and documentation was reviewed by Roy Glass. An editorial review of the documentation was done by Liska Snyder.
Related_Spatial_and_Tabular_Data_Sets:
None
Other_References_Cited:
Domaratz, M.A., Hallam, C.A., Schmidt, W.E., and Calkins, H.W., 1982, Digital line graphs from 1:2,000,000-scale maps (USGS cartographic standards): U.S. Geological Survey Circular 895-D, 40 p.
Notes:
None
None planned.
Point_of_Contact USGS-WRD
Since the coverage was created from 1:2,000,000 (DLGs), caution should be used if the data are used with relatively small scales.
Alaska Department of Natural Resources, USGS EROS field office, Anchorage, AK
None
Unknown.
Standard items are contained in the polygon attribute table with the exception of the item MAJ. If MAJ = 40, the polygon is a glacier. If MAJ is not 40, the polygon is not a glacier. Standard items are contained in the arc attribute table with the exception of the item ARC_ON. If ARC_ON = 1, the arc was added to reduce the size of the glacier. If ARC_ON = 0, the arc was not added.