8/28/2023 0 Comments Usgs raster data![]() ![]() Since the 1970s, dozens of formats have been created based on various data models for various purposes. I’ve also noticed that visiting the page on Internet Explorer 7 can consume all of your available system memory for some reason, so expect the site to run slowly using that browser once again, not a problem with Firefox.A GIS file format is a standard for encoding geographical information into a computer file, as a specialized type of file format for use in geographic information systems (GIS) and other geospatial applications. You’ll need to have pop-ups enabled on your web browser to download data this wasn’t a problem on Firefox, but gave me headaches with Internet Explorer 7. There’s a full tutorial page on the USGS website that explains its interface better than I could. I’ll be using GeoTIFF DEM data in all the examples I’ll be posting about, since that seems to be one of the more widely-compatible DEM data formats. ![]() You also have a choice of data formats for DEMS: ArcGrid is the default, but you can also choose GeoTIFF, BIL or GridFloat as alternatives by clicking on the “Modify Data Request” button on the SDDS Request Summary Page”, and choosing an alternate data format from a drop-down menu. A 1/3 arc-second NED file is 9 times larger than a 1 arc-second NED file covering the same area. sand dunes.Īs you go to higher resolution, you can see more details, but your filesize gets larger as well. SRTM also has problems with terrain that’s transparent to radar, e.g. The patching done to fill holes in SRTM data is problematical I once got a SRTM DEM for an area in Mexico that showed a mountain with a hole in the top that went all the way down to sea level. In the US, I recommend using the NED data whenever you can. SRTM 3 arc-sec – 90-meter data, “patched”įor the world outside the US, only SRTM 90-meter data is available from the USGS, so if you have a better source for the data, you should use that instead.SRTM 1 arc-sec – 30-meter data from the Shuttle Radar Topography Mission, with voids and data issues “patched”.National Elevation Dataset (1 arc-second) – Roughly 30-meter spacing covering most of the US. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |