Finding Basemap Data for fGIS

To begin a map in fGIS, you must load at least one basemap layer (a geo-referenced aerial photo, scanned map or any geo-referenced vector layer). All the layers in a project must also be based on a uniform projection and datum. So where does one get consistent basemap data to start a project?

If you are a Wisconsin forester, standardized data sets are available from the DNR Private Forestry Specialist.

For other North American users, the simplest approach to getting aerial photos and vector data in a uniform projection might be to start with TerraServer images and US Census TIGER vector line data.

• TerraServerUSA is an excellent source of aerial photographs and USGS topographic maps. The freeware programs USAPhotoMaps and MapShots® TerraFetch can retrieve TerraServer images and save them as georeferenced (UTM-NAD83)  images to use in fGIS.

• US Census TIGER line data provides political boundaries, roads, streams, water bodies, etc., in addition to demographic attributes. Census TIGER line data is available from many sources, including ESRI® or MapShots®. If the source data is in Geographic (lat/lon WGS84) format (which is generally the case), it can be converted to the UTM-NAD83 coordinate system with the fGIS Shapefile Projection Utility.

• The USDA Geospatial Data Gateway provides One Stop Shopping for natural resources or environmental data at anytime, from anywhere, to anyone. The Gateway allows you to choose your area of interest, browse and select data from our catalog, customize the format, and have it downloaded or shipped on CD.

Most state conservation departments offer spatial data free or at minimal cost. You can use an Internet search engine to look for GIS data for your area; e.g., use Google to look for "Alabama GIS Data", "California Spatial Data", etc. Search for "Free GIS data" and you'll be astonished at the number of hits. There are also many commercial vendors of spatial data (e.g., MapMart, GeoCommunity, etc.)

Public Land Survey System (PLSS) data (section lines and corner nodes) can be especially helpful to resource managers who must identify property boundaries. Many state resource agencies offer PLSS data. The US Bureau of Land Management offers PLSS data for many states. You might also want to search for PLSS data for your area with Google. See webGIS for PLSS DLG shapefile data derived from USGS quadrangle maps.

Use 3DEM for Shaded Relief Models