High Resolution Elevation Data Available on DNR Data Deli By Tim Loesch, Minnesota Department of Natural Resources
High resolution elevation data products have been added to the DNR Data Deli from the recent LiDAR collection project conducted in portions of the Red River Watershed in 2006. The data products include contour line features along with gridded DEMs. To access the Data Deli, go to: http://deli.dnr.state.mn.us, then look for the "High Resolution Elevation Contours" and "High Resolution Elevation Model (DEM)" layers.
Data Partnership and Area Covered
The data was collected as a partnership of state, federal and local entities including Norman, Mahnomen and Clay counties, the Minnesota Department of Transportation, the Minnesota Department of Natural Resources, the White Earth Indian Reservation, the Wild Rice Watershed District and the Federal Emergency Management Agency.
The map below shows the area of the collect. The green areas represent data capable of producing 1-foot contours while the purple areas represent data capable of producing 2-foot contours at the 95% confidence interval.
The grids are 3-square-meter cell size and were derived from LiDAR points and edge-of-water breakline features that were stored in an ESRI Terrain dataset. The vertical values for this dataset are meters represented as floating point numeric values. Remember that when you download gridded products from the Data Deli that they are in ASCII transfer format. If you are using ArcMAP you will need to use the "ASCII to Raster" tool found in the "Conversion Tools: To Raster" toolset.
The contour data is either 1- or 2-foot contours, depending on the data used to derive the contours (see graphic). These data are 3D polyline shapefiles and their elevation values are in feet.
Both data sets are in the UTM Zone 15 projection, referenced to the NAD83 horizontal datum and to the NAVD88 vertical datum. They are quite large and are tiled in U.S. Geological Survey quarter-quadrangle format to facilitate rapid downloading.
The LiDAR data will also be distributed from the USGS CLICK site at http://lidar.cr.usgs.gov/ and is in the process of being integrated into the distribution system. During a recent check of the site the data is not currently posted but it is expected soon.