Flathead Basin Mapping Project, 2009
These data are 2-foot topographic contours of the Flathead Basin, including the Flathead Valley north of Flathead Lake and the immediate areas around Whitefish Lake, Flathead Lake, Swan Lake, and Polson. These contours were derived by automated methods from LiDAR point cloud data collected between September 22 and September 29, 2009.
These data are in Montana State Plane coordinates, NAD83, HARN. The horizontal units of the coordinate system are U.S. Survey Feet. The vertical datum is NAVD 88, Geoid03.
The data originally received from the contractor were highly detailed ESRI file geodatabases, with many areas having line segments with several vertices per linear foot on the ground. These data have been smoothed by the State Library to reduce the number of vertices by over 50 percent and make the data available in shapefile format, while assuring that no contour line deviates by more than 1.5 inches from the position of the original.
These data may be viewed by anyone with our Online Map Viewer or accessed as web services that allow seamless access to the data without the need to download individual tiles. This web site is intended for quick access to data for a small area. If you need this data for a large area sent to you, please contact the State Library.