The accepted framework layer for the elevation dataset in Montana is the USGS National Elevation Dataset. To reduce duplication of effort this data will no longer be available directly from the Montana State Library. Data can be downloaded from the USGS National Map Download Platform at: http://viewer.nationalmap.gov/viewer/.
Current Longitude/Latitude data available from the USGS
- 1×1 degree blocks(approximately 45×70 miles): Tiled NED Tool - specify the region and the application creates a list of files needed for download to cover the specified region.
- Data for a precise area: Use the National Map Viewer to zoom to an area of interest. Select the Cart tab on the left, the Advanced tab on the right, click on Download, and then select the "Click here to download by current map extent" link.
NED 1- and 1/3-arc-second data will be available through prepackaged, downloadable, 1- degree tiles in ArcGrid and GridFloat formats only. Users can still define custom areas of interest. However, all tiles intersecting the area of interest will be included in the delivery. The ground resolution of 1-arc second data is approximately 30 meters, and the resolution of 1/3 arc-second data is approximately 10 meters.
Note: As part of the National Geospatial Program's geospatial data delivery plan for delivering data from a public internet cloud provider by the end of 2013, The National Map is preparing prepackaged, staged products for faster and more efficient downloads. Beginning December 18, 2012, NED 1- and 1/3-arc-second data will be available through prepackaged, downloadable, 1- degree tiles in ArcGrid and GridFloat formats only. Users can still define custom areas of interest. However, all tiles intersecting the area of interest will be included in the delivery.
In addition, beginning with the April 2013 release of the NED, it is anticipated that all elevation products (1-, 1/3- and 1/9-arc-second DEMs) will be available as prepackaged, downloadable files in .img format, a robust format easily read by nearly all GIS software. Due to 1/9 arc-second data's very large size, it will only be available as prepackaged data in .img format through online download starting with the April NED release. And while USGS continues to offer ArcGrid and GridFloat formats through our bulk order process, all other format options for on-line download of 1/9 arc-second DEMS will no longer be available after the move to staged products is completed. To assist users in this transition to our new product format offerings, we are also providing downloadable file conversion scripts to assist users that need the data in other formats.