Digital Line Graphs are maps derived from information gathered by the USGS. DLGs can be broken down to nine layers: Public Land Survey System which shows townships, Boundaries such as state, county, city etc. Transportation (red lines on the map above) which includes roads and railways. Hydrography shows water (blue lines on the map above) and Hypsography (brown lines) show contour of land. Non-vegetative features, man-made features and vegetative surface coverage are three more layers and the last layer is survey control or markers.
No comments:
Post a Comment