Data Sources and Management

1) Digital spatial data is common, inexpensive, and easy to use, but sometimes a digital raster graphic can show more information more neatly.

2) DOQs are digital ortho quadrangles, which are corrected and georeferenced photographic maps.  The corrections are to minimize distortion from camera tilt and terrain displacement.

3) The National Wetlands Inventory consists of wetland maps produced by the Fish and Wildlife Service.  Topographically Integrated Geographic Encoding and Referencing (TIGER) consists of demographic maps produced by the Census Bureau.  Land Use Land Cover (LULC) Data consists of land use/cover maps produced by the US Geological Survey (USGS) from aerial photography, while National Land Cover Data (NLCD) consists of land cover maps produced by the US Geological Service from satellite maps.

4) DEMs (Digital Elevation Models) are elevation data in raster format, created from ground and aerial surveys of original elevation measurements.  National Elevation Datasets (NEDs) are seamless rasters created by the USGS from merging the best DEMs.

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2a) The feature datasets are Basemap and Hydrology.

2b) The feature classes in the Hydrology dataset are NHDFlowline, NHDPoint, NHDWaterbody, and Watersheds.

2c) NHDFlowline is a line layer, NHDPoint is a point layer, and NHDWaterbody and Watersheds are polygon layers.

3a) Topoq24.shp is a vector data layer.

3b) Topoq24 is a shapefile.

3c) There is metadata associated with Topoq24.shp

3b) NHDFlowline is a geodatabase.

3c) There is metadata associated with NHDFlowline.

3d) Three keywords used to describe NHDFlowline are Hydrography, Stream/River, and Lake/Pond.

3c) The USGS Earth Science Information Center is the author of NHDFlowline.

4a) There is still metadata associated with the layer.

6b) The Canoga Park USGS_QD_ID is 34118_B5.

7) The DOQQ is black and white.

12a) The lacounty_lu01.shp no longer appears, because its original data source no longer exists.