The Shuttle Radar Topography Mission (SRTM) obtained elevation data on a near-global scale to generate the most complete high-resolution digital topographic database of Earth. SRTM consisted of a specially modified radar system that flew onboard the Space Shuttle Endeavour during an 11-day mission ...

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17
votes
7answers
5k views

Are there open access terrain tiles with a permissive license like OSM?

Are there open access terrain pyramidal map tiles with a permissive usage license like OpenStreetMap's? I'm building aviation-related maps with Polymaps and need a good raster basemap. The Google ...
12
votes
5answers
6k views

How to get an elevation profile for a gps track?

I'd like to get a reasonably accurate elevation profile for a track recorded with a GPS (which often has very unreliable altitude data and occasionally none at all, depending on the model.) Does ...
9
votes
4answers
4k views

Downloading SRTM data

Is there an easy way to mass download SRTM data? The data is published for download here, but it's sliced into thousands of small files, and I don't see an FTP option for more efficient ...
6
votes
3answers
5k views

How to use SRTM Global DEM for Slope calculation?

I have downloaded SRTM GDEM (~90 km resolution). I am using ArcGIS 10. I have tried to use spatial analyst to compute for slope. However, I can not compute for the slope. The output values has only ...
6
votes
5answers
342 views

Looking for (nearly) worldwide elevation data

I know the raw ASTER and SRTM datasets. Is there any error corrected version available? Or did anybody already combine the data? At least the ASTER data often misses tiles for costal regions (if there ...
6
votes
3answers
8k views

How to extract elevation from .HGT file?

I want to asign a specific long/lat position on a map the elevation from SRTM3 data files, but have no idea how to find the specific value. So I want some example of how I can find in N50E14.hgt ...
5
votes
4answers
814 views

Does a value in srtm dem file refer to the center or corner of a cell?

I'm working with srtm dem files. They are ascii text files containing a table/grid of elevation values. At the top of the file is some metadata to locate the grid in lat/lon: xllcorner ...
5
votes
1answer
421 views

How to read Geotiff tags and pixel per pixel values using GDAL C#

I'm new here and I'm new at programing with GDAL C#. My question is how I can get the value of SRTM GEOTIFF pixel to compare with it's neighbors, and how can I get the values of Geotiff tags.
4
votes
2answers
135 views

Why are poles missing from GIS topographic data?

Why are poles data missing from most topographic resources ? Data from 60⁰ to 90⁰ lat frequently missing from topographic GIS data. Example with SRTM4.1: Common sense or deduction lead me to think ...
4
votes
2answers
1k views

How to read GeoTIFF using PHP?

My current pet project involves creating a web service that uses the CGIAR SRTM worldwide elevation data set. Each request to the service will query for elevation data from a small geographic area. ...
4
votes
3answers
757 views

How to get the elevation of the areas in a raster file from SRTM?

I have an SRTM elevation map. How do I get the elevation of each point in the map? I am using GRASS. Is there a GRASS script to do such?
4
votes
1answer
125 views

Weird raster visualisation

Using the hillshade tool (Arcmap 10) on a 30m SRTM raster downloaded from NED the result is the one in the picture. Why are there those crossed lines all over the raster? How could I remove them? ...
4
votes
0answers
239 views

How to stop gdalwarp creating world-spanning outputs near the dateline?

I'm using gdalwarp to manipulate SRTM tiles near the the dateline (i.e. 180°, aka the antimeridian). SRTM tiles have a very slight (1/2 pixel) overlap with the meridian. You can see this using ...
3
votes
3answers
83 views

Bad SRTM files?

I have noticed that between 1-3% of SRTM .hgt files downloaded for a continent when un-zipped are of TGA image, font image or text format and do not contain elevation data. Results are the same ...
3
votes
2answers
195 views

How to make the arrows in d.rast.arrow GRASS script visible?

I'm trying to create a Flow or directional raster map (with arrows) from an SRTM elevation map that I downloaded from CGIAR. I already created an aspectMap to be used for the d.rast.arrow. I used ...
3
votes
1answer
491 views

Is it possible to produce a decent looking shaded-relief map at 50K-scale-or-larger using SRTM3 DEM?

I'm trying to make a decent-looking shaded-relief map of a particular area in 50K-scale-or-larger using open-source tools. The best (and free) option I have for DEM data for that area right now is the ...
3
votes
1answer
557 views

Correct ASTER with SRTM or Topographic Map

I have a problem with my DEM again. I decided to use ASTER GDEM2 (for different reasons). ASTER GDEM2 have its problems, I know, and I dont want to discuss that again. I have to use it, because SRTM ...
3
votes
1answer
709 views

Export SRTM30 Dem file as 3d

i have downloaded some SRTM Dem files here: http://dds.cr.usgs.gov/srtm/version2_1/SRTM30//srtm30 They are from the USGS site. I would like to export them as 3d. I have ran through a few ...
3
votes
1answer
537 views

Where can I find USGS SRTM 3 index grid or what procedure should I employ to select tiles?

I would like to download all USGS SRTM 3 tiles for Ontario, Canada from the USGS site: http://dds.cr.usgs.gov/srtm/version2_1/SRTM3/North_America/ Where can I obtain the index that will assist me in ...
3
votes
1answer
94 views

Practical tools to delineate large scale watershed?

I would like to do some watershed delineation at national/regional level (using SRTM-90 data). I have experimented with r.watershed (GRASS 6.4.3) but it fell over when I tried to do big stuff. I ...
3
votes
2answers
58 views

Is SRTM 3 second arc free of non-terrain features?

I made an elevation map of my study area in Macapa, Brazil. But the region has the average elevation lesser than 30 m as I can see from my map derived from SRTM 3 second arc. According to my ...
3
votes
1answer
57 views

artifacts in SRTM contour layers processed with GDAL tools and rendered with mapnik

Here is my workflow for importing individual SRTM tiles into postgis using the GDAL utils and rendering a png using mapnik: gdal_fillnodata.py -srcnodata -32768 gdal_contour -i 10 -a ele -snodata ...
3
votes
2answers
103 views

Basic question about downloading SRTM 3 arc resolution data

I want to be able to download high resolution 3 arc degree resolution (90 meters) from NASA's earthexplorer.gov site. However it is a bit confusing for a beginner like myself. I want to be able to do ...
3
votes
1answer
705 views

What is difference between GeoTIFF and Esri ASCII grid file formats for SRTM data?

what is the difference between the ArcInfo ASCII format and the geotiff file format when downloading the SRTM data. I downloaded the tiles (21) for the Tibetan Plateau and imported thme into ArcMap ...
3
votes
2answers
266 views

Hillshade for 30m NED at continental scale

I'm new to terrain analysis. I have a 30m NED DEM (.tif) for the conterminous US. I would like to generate a nice looking hillshade for the US, but it looks bad - as in pixelated and rough (See ...
3
votes
1answer
95 views

How to convert the SRTM DEM orthometric to ellipsoidal heights using ArcGIS or others GIS?

Recently I got the SRTM DEM from Cgiar,which based on WGS84/EGM96. and I merged the tiles to one tiff file. I want to get the WGS84 ellipsoidal heights. According the steps from the Arcgis Help 10.2 ...
3
votes
0answers
45 views

Questions about SRTM , .hgt format and the sea level/coastline

What a nice place here ! The questions/answers system is very elegant. I have read and get some useful informations allowing me to write a little .hgt reader... I am working on C.G.I and create 3d ...
2
votes
1answer
159 views

SRTM v4 hillshade very grainly surface

I'm a newbie in this field and I'm trying to create a hillshade from a SRTM v4 geotiff. The result is not what I expected. Surface near coast and the fields is very grainy. Thank you for your ...
2
votes
1answer
67 views

How to remove/disable last row/column of SRTM GeoTIFF in QGIS?

I've started using QGIS yesterday, and one of my main reasons to use it is to apply colormapped SRTM v4 over Google aerial imagery. Everything is working fine, except that SRTM v4 elevation tiles ...
2
votes
1answer
50 views

Read In SRTM HGT elevations using Java

I have read the following posts on reading in SRTM HGT elevations- How do you convert SRTM HGT elevations from WGS84 into meters above sea level? and How to extract elevation from .HGT file? I am ...
2
votes
2answers
61 views

How to remove the no data area (sea) from a raster in arcmap?

I have some difficulties removing the no data part from a Geotif SRTM . I need to remove all sea part. Im new in arcgis and, help is appreciated. Thanks There you go Sir This is the result i ...
2
votes
3answers
2k views

How to use SRTM30 Plus data with QGIS or other GIS tool?

I am trying to access the new Bathymetry data published here: http://topex.ucsd.edu/WWW_html/srtm30_plus.html Is there a way QGIS or similar tool can read these files. Nothing seems to be working, ...
2
votes
2answers
2k views

Converting ASCII grid/NTF to SRTM/DEM

I want to use the Ordnance Survey Land-Form Panorama product in some software called Maperitive, which can read custom SRTM DEM files. The data is provided in the following formats: DXF [Contours] ...
2
votes
2answers
38 views

Handling voids in SRTM3 data

When I actually work with SRTM 3 data in a meteorological application and especially when doing simulation over mountainous regions I expected and found a lot of voids in SRTM3 data. Has there been ...
2
votes
1answer
445 views

Conversion from CGIAR GEOTIFFs to SRTM3 like HGTs

Im writing a C program for querying height information from SRTM data. Since reading directly GeoTIFF format is tough job, I decided to load HGT format, which serves great for the purpose. Since ...
2
votes
2answers
559 views

How to query data from a vector map (shapefile)?

We want to obtain the specific place of the boundaries of a shapefile. We want to be able to get the points of each polygon corresponding to a specific place in order to use these data in an ...
2
votes
1answer
27 views

gdaldem output file size explodes

I want to create a color-relief and a hillshade with gdaldem and use them with mapnik. System: Ubuntu 14.04 LTS Server, gdal-bin 1.10. Here are my steps: Download all SRTM tiles from ...
2
votes
0answers
37 views

Distributing processed SRTM data legally?

I'm working on different maps, based on SRTM data. The goal is to lay out the maps at a park entrance against a little money for the printing and my personal costs. The SRTM 4 data from CGIAR I ...
2
votes
0answers
160 views

How to best intersect vector data with raster data?

I have Open Street Map [OSM] data imported so that I can access the geometry of buildings. I have also loaded SRTM digital height data from NASA from a GeoTIFF raster. I have projected the raster into ...
1
vote
3answers
205 views

SRTM NASA hillshade grainy appearance

I'm trying to create a hillshade surface from SRTM files downloaded form Earth Explorer, but the appearance is not the expected. It has a grainy surface that I would like eliminate to have a ...
1
vote
2answers
239 views

Where can I programmatically download SRTM_V4.1 data?

SRTM v4 is an effort by the folks at CIAT-CSI to scrub, polish, and remove gaps in the raw SRTM data released by NASA (SRTM 3). One userfriendly interface : http://dwtkns.com/srtm/ provides ...
1
vote
2answers
2k views

How to use SRTM DEM files for shaded relief in ArcMap?

I would like to create a nice shaded relief for France using SRTM3 data. Most of the threads on the subject are from awhile ago, when ArcMap was not able to import these without changing the file ...
1
vote
1answer
474 views

Using SRTM data, how to get the coordinates of the peaks visible from a location?

Using SRTM data and a coordinate-altitude database of the peaks, I want to get the coordinates of the visible peaks from my location. I want to make an application similar to this. How is this ...
1
vote
1answer
62 views

Need to extract coordinate information from SRTM 3 files

From this link here - http://www2.mmm.ucar.edu/wrf/users/docs/user_guide_V3/users_guide_chap3.htm#_Writing_Static_Data I wrote code in java to transform SRTM3 data into WRF geogrid data. I read the ...
1
vote
1answer
84 views

How to: script convertion from SRTM to 3D printable file?

Given a STRM3.tiff file as input. How to convert this STRM.tiff file into a 3D printable file ? which I may load into most 3D printers' sofwares. My objective is to print some terran, lunar, or ...
1
vote
1answer
154 views

How to compare accuracy of two DEM using GRASS

How do I compare accuracy of two DEM data (lidar and srtm) (possibly through rmse) using GRASS GIS? thanks
1
vote
1answer
147 views

How to distinguish SRTM from DTED using C#?

Does anyone know how to easily distinguish between SRTM vs DTED programmatically without opening file metadata header? both are .dt1 or .dt2 extensions.
1
vote
1answer
231 views

How can I recalculate an attribute based on overlap with another layer?

I have 2 layers: The first one is a point Layer (converted from SRTM) with height information. The second one is a polygon layer (shows the forest). I want to reduce the height value - let's say ...
1
vote
1answer
515 views

Using Latitude and Longitude with SRTM3 DEM file

I am new to working with DEM files but have a need to be able to work with SRTM3 DEM files to calculate elevation given a Lat,lon coordinates. I understand from reading the documentation that the ...
1
vote
1answer
24 views

how use height tag data in Project-OSRM

I am using Project-OSRM in my project . All is works . But I need use elevation data. Downloaded osmosis master . And SRTM plugin added to osmosis. Also this worked fine . SRTM plugin started and I ...