Download srtm hgt file

The radars used during the SRTM mission were actually developed and flown on two Endeavour missions in The technology was modified for the SRTM mission to collect interferometric radar, which compared two radar images or signals taken at slightly different angles.

This mission used single-pass interferometry, which acquired two signals at the same time by using two different radar antennas. An antenna located on board the space shuttle collected one data set and the other data set was collected by an antenna located at the end of a meter mast that extended from the shuttle. Differences between the two signals allowed for the calculation of surface elevation.

Endeavour orbited Earth 16 times each day during the day mission, completing orbits. This version was then edited or finished by the NGA to delineate and flatten water bodies, better define coastlines, remove spikes and wells, and fill small voids. Data for regions outside the United States were sampled at 3 arc-seconds approximately 90 meters using a cubic convolution resampling technique for open distribution.

The voids occur in areas where the initial processing did not meet quality specifications. Since SRTM data are one of the most widely used elevation data sources, the NGA filled the voids using interpolation algorithms in conjunction with other sources of elevation data.

Some tiles may still contain voids. Users should check the coverage map in EarthExplorer to verify if their area of interest is available. EarthExplorer offers SRTM data with a regularly spaced grid of elevation points in three file formats:. The accuracy of most of the data is up to SRTM standard, but there may be some slight local terracing and pockets of inaccuracy, especially in Italy.

Click here to access these data. These data are now only downloadable via the coverage map. They no longer downloadable from tables. The new edition, created by Aleksandr Yashin , is smoother and more accurately placed. Data Quality and Credits. The extent of coverage eastwards into northern Russia is shown on the coverage map. The areas shown in red were added or improved on 15 March ; advanced DEM algorithms have now been applied throughout these areas. The source maps are in scale , 60'x20' west of and in part of zone 36, and in the Ural mountains.

Elsewhere they are in scale , 'x40'. SRTM data in these latitudes are affected by boreal forests, which the radar did not penetrate, and may therefore appear to be higher and more noisy than the map generated data.

In this version, the source contours remain unchanged, but the interpolation algorithm used to create the DEM has been improved. Smoother results with fewer artefacts should be noticeable, especially in areas of low relief. GeoTiff files, including UTM projected data, and source contour and lake text files, have also been created. The GeoTiff files have sub-metre vertical resolution which some users may find helpful.

A GeoTiff sample and contour samples can be downloaded; anyone interested in the complete sets can contact me. My thanks to Christoph Hormann for the new DEM data and the application of the above algorithm , and to Aleksandr Yashin for identifying various errors and areas for improvement.

Since 21 April , all the above data have all been corrected to the standard WGS84 datum used by SRTM, and contain input from hydrographic features. This may appear to show more detail that the other data. This is partly because, from K or even K maps, it is not possible, especially in areas of lower relief, to capture the level of detail that was captured by SRTM; but it should also be noted that some of the SRTM "detail" is at tree top level.

SRTM data were captured in February , when the snow-laden pine forests that dominate the area would have prevented the penetration of the SRTM radar to ground level. If SRTM coverage were worldwide, or some other SAR data source became available to the general public, there would be no need for this page. But to the best of my knowledge, this is not about to happen.

Some high relief parts of Europe are covered at 1" resolution. The main issue with GDEM is artificial trash on the flat sands; areas of medium to high relief are generally well covered by this source. I am grateful to Trond Nesoen for the provision of this. For accuracy information, see the above link. For realistic rendering, images generated from these should be reprojected to UTM or polar; both 3dem and Global Mapper will do this. Sign up to join this community. The best answers are voted up and rise to the top.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Asked 10 years, 10 months ago. Active 5 years ago. Viewed 12k times. Is there a better resource for getting this data? Improve this question. Add a comment. Active Oldest Votes. It has been eaten. Ah, my bad. I thought I was seeing the same site.

Thanks a lot for pointing that out. I saw that site before and completely forgot about it. The USGS sit used to have a terrible interface. I had a look this after noon and it seems a lot better and easier touse.