Digital elevation model (DEM)

Posted by Caitlin Dempsey on 8/24/00 • Categorized as Glossary

Definition: A topographic surface arranged in a data file as a set of regularly spaced x, y, z coordinates where z represents elevation.

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1 Comment

  1. Chris
    February 23, 2010 • 5:05 pm

    Hello, I’m looking for anyone who may know where I can find the highest quality DEM data for free on the web. Yes, I have already made a visit to the USGS Seamless data and have found this data to be quite poor compared to what I found on the BLM website. More specifically, I’m looking for DEM data that covers the Pacific Northwest Region (WA, OR, MT, ID, and BC Canada).

    I do have a DEM of this region that was downloaded by a person in our office who preceded me but he did not identify the source of his data. I have searched the metadata as well with no luck. It is by far the best quality data that I have seen. The default Hillshade on this specific DEM is very clear visually on multiple scales. So I know the information is out there. Now I’m trying to expand the region of responsibility, but I cannot, for the life of me, find where this data came from. The best data I have found so far is a finished version of SRTM 1 arc second data and the BLM DEM data which contain some problem areas and fail to reach the quality of this mystery DEM data set.

    The only other option I can think of at this point is that the data was processed somehow with a raster calculator or neighborhood statistic. I’ve made attempts at using the Swiss Model, yet the quality is still not matched. Nor is there any indication in the metadata of geoprocessing this DEM other than being mosaic/ tiled.

    Any help will be GREATLY appreciated.

    Thank you

    Chris

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