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--- arma3:terrain:heightmap-real-world-data [2017-02-07 09:44]
snakeman created heightmap-real-world-data initial page.
+++ arma3:terrain:heightmap-real-world-data [2018-07-09 06:27]
snakeman added header.
@@ Line 11: / Line 11: @@
 **Best online heightmap data?**
-At the time of writing this page the best heightmap source is **Shuttle Radar Topography Mission (SRTM GL1) Global 30m**.
+At the time of writing this page the best heightmap source is **Shuttle Radar Topography Mission (SRTM GL1) Global 30m** found from OpenTopography site or from global mapper online sources.
+**ARC Seconds**
+Arc second is 30 meters\\
+Arc second is 90 meters
+See also [[arma:terrain:dem_resolution|arma terrain DEM resolution]].
 ====== OpenTopography ======
-This is very good site to download elevation data, it has nice coverage and nice user interface.
+This is very good site to download elevation data, it has nice coverage and nice user interface. Remember global mapper online sources includes this same data.
 Go to [[http://opentopo.sdsc.edu/lidar?format=sd|OpenTopography]] web site, click Global Data tab.
@@ Line 27: / Line 34: @@
 Once you have zoomed enough in to a smallish area, click "select a region" button in left side of the globe map screen. Mouse cursor changes to a cross now and you can drag a box to select region. Below you can see the data selection coordinates.
+OpenTopography site limits digital elevation map downloads to 450,000 square kilometers (which is huge in arma3 terms).
 In coordinates box, if you choose to do so, you can tick "manually enter selection coordinates" box and then manually type in lat/lon coordinates. This is the only sure way to grab perfect square power of two data selection.
@@ Line 40: / Line 49: @@
 Once processing is done you get "Raster Job Report" page which has your download. On "Download compressed raster results:" click the "rasters_srtm.tar.gz" (or rasters_alos.tar.gz if you chose ALOS) downloadable file to... you know, download.
-This download is always the same file name so **please be careful and unpack this file into a directory**, use winrar RMB "extract to rasters_srtm/" and then **rename the directory to some good name which you recognize** because the terrain Asc ASCII Grid file inside is also named just "output_srtm.asc" every time you download new data. This way you never overwrite your existing terrain data downloads.
+This download is always the same file name so **please be careful and unpack this file into a directory**
+Use WinRAR / 7Zip RMB "extract to rasters_srtm/" and then **rename the directory to some descriptive name which you easily recognize** because the terrain Asc ASCII Grid file inside is also named just "output_srtm.asc" every time you download new data. This way you never overwrite your existing terrain data downloads.
-You should be able to import the tar gunzip (.gz) file into QGIS, however you should unpack it first like explained above. You can save the heightmap from QGIS into TIF file format and then read the tif with L3DT. L3DT can then save the heightmap as ASCII grid or XYZ.
 ===== SRTM =====
@@ Line 75: / Line 85: @@
 Click results button.
+====== High Res Heightmaps ======
+https://environment.data.gov.uk/ds/survey/index.jsp#/survey
+https://pugetsoundlidar.ess.washington.edu/index.html

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