dem

The National Elevation Dataset (NED) is the primary elevation data product of the USGS. The NED is continually updated by the USGS. The NED is a seamless dataset with the best available raster elevation data of the conterminous United States, Alaska, Hawaii, and territorial islands. The NED is derived from diverse source data that are processed to a common coordinate system and unit of vertical measure. The AGRC has a statewide collection of 10 and 30 meter DEMs.

These elevation models were created from the best available DEMs. Much of the line distortion is then filtered out of the NED. Because of the filtering it gives a clearer picture than the standard DEM.

To make the .dem file useable in ArcMap it needs to be converted into a Raster/Grid. In ArcMap use the toolbox Conversion Tool -> DEM to Raster.

This dataset is projected to UTM Zone 12 NAD83 meters. The vertical datum is NAVD88.

Related Resources

General Utah GIS data inquiries: Rick Kelson at (801-538-3237)

Updates
ned

A digital elevation model (DEM) is a digital file consisting of terrain elevations for ground positions at regularly spaced horizontal intervals. This is a legacy dataset and does not get updated like the NED does. The USGS produces five different digital elevation products. Although all are identical in the manner the data are structured, each varies in sampling interval, geographic reference system, areas of coverage, and accuracy; with the primary differing characteristic being the spacing, or sampling interval, of the data. The AGRC has a statewide collection of 10, 30, and 90 meter DEMs.

AGRC has populated it's FTP site with DEMs from the USGS for the State of Utah. There is a statewide coverage of 10, 30, and 90 meter DEMs. They are in a self extracting .exe format.

The DEMs are separated into three directories. For 10 and 30 meter DEMs refer to the Find a DEM lookup for USGS Quadrangle names and associated DEM name. For 90 meter DEMs refer to the 90meter dem image map.

In order to make the .dem file useable it needs to be converted into a Raster/Grid. In the ArcMap toolbox use the Conversion Tool - DEM to Raster.

All DEMs are UTM Zone 12 NAD83 meters. The vertical datum is NGVD 29.

Related Resources

General Utah GIS data inquiries: Rick Kelson at (801-538-3237)

Updates
lidar

Light Detection and Ranging elevation data is an optical remote sensing technology that can measure the distance to, or other properties of a target by illuminating the target with light often using pulses from a laser. Currently this is the most accurate elevation dataset AGRC has but it is only available for a few areas of the state. In addition to the bare-earth DTMs and first-return DSMs, most LiDAR data also has point clouds of elevation information. Exploring LiDAR

AGRC has partnered with different agencies over the years to acquire LiDAR data.

Year Resolution Areas Information
2017 .5 meter Washakie and Whites Valley View
2016 .5 meter Monroe Mountain View
2013-2014 .5 meter Wastatch Front and the Wastatch Fault View
2011 1 meter Great Salt Lake, Cedar Valley, Hurricane Fault View
2006 1 meter Wasatch Front, Iron County, Heber Valley View
Related Resources

General Utah GIS data inquiries: Rick Kelson at (801-538-3237)

auto-corr_dem

AGRC has a statewide coverage of 5 Meter Auto-Correlated DEMs in addition to some 2 meter areas. The DEMs were created from the imagery collected during the 2006 NAIP and HRO aerial photography flights. The auto-correlation process is not as rigorous as other methods of elevation modeling such as photogrammetry, lidar mapping, radar mapping, etc, and therefore end-users should be aware that anomalies are expected within the elevation dataset. In comparison to the USGS NED dataset, the 2 and 5-meter DEM provides higher resolution and horizontal accuracy but anomalies are present within the data.

The DEM files are stored as .asc formatted files and are ~10MB per 2,000 X 2,000 meter block. This data is in a UTM NAD83 meters projection and has a Vertical Accuracy of RMSE 4.27' - NSSDA 95% 8.4' and a Horizontal Accuracy NSSDA, radial RMSE of 4.4', 95% confidence 7.6', NSSDA 95% of 5.2m. Please reference the Auto Correlated DEM 2m shapefile as an index to determine which files to download.

2 meter DEM
5 meter DEM
Related Resources

General Utah GIS data inquiries: Rick Kelson at (801-538-3237)