Getting USGS Data

Free

• Some of their data is available from free, online, at USGS Geographic Data Download
• Unfortunately, nearly all of the elevation and vector data is in the awkward SDTS format
• You can also browse and directly download some raster data through the National Map Seamless Data Distribution System
  • currently, this is limited to SRTM, NED (National Elevation Dataset), and some small areas of orthoimagery
  • to check if an area has orthoimagery, you can consult the High Resolution Orthoimagery List
  • you can specify the exact rectangle you're interested in, but only in Geographic extents (not UTM etc.)
• For DOQ and DRG, if you don't care about exact resolution, you can use the free terraservice.net (TerraServer-USA)
  • it is implemented both with a web interface and as a direct WMS, so you can access it directly from any WMS client, such as VTBuilder
  • as of 2004, it even includes some color DOQ, which are also found in the National Map server
  • for the WMS address, for capability and maps, use:
    • http://terraservice.net/ogccapabilities.ashx
    • http://terraservice.net/ogcmap.ashx
  • see TerraServer Web Services for more details
• All DRGs are also online free at the Libre Map Project
• If you only need to get individual elevation points, the USGS Elevation Query Web Service return the elevation in feet or meters for a specific latitude/longitude (WGS 1984) point from the USGS Seamless Elevation datasets.

Quad Names

• traditionally, most USGS data was on printed maps, 7.5 minutes by 7.5 minutes in size, and most of their digital data follows this structure
• each quadrilateral map ("Quad map") has a name, which is useful for locating and referencing the data
• unfortunately, many download interfaces won't produce a map of these quads
• there used to be a USGS Map Finder until they took it offline; their new USGS Store doesn't yet have a geographic map locator
• you can still use the USGS Data Center, 1:24k DLGs interface to graphically browse for quad names
• alternately, there are data sources such as usgsquads KMZ 24k which can be viewed in Google Earth to quickly find a quad name, although their links all go to their company which sells the public-domain data

Purchasing

• most of their data, especially higher resolution products and older file formats, must be ordered at the cost of $1 per file, plus $45 per order
• their new web interface for ordering is USGS EarthExplorer
• you can have them either mail you a CD, or arrange for FTP download
• if you prefer to pay by the download and don't mind lots of advertisements, you can also use authorized USGS distributor GIS Data Depot