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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15
votes
7answers
4k 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
4k 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
3k 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
5answers
274 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 ...
4
votes
3answers
5k 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 ...
4
votes
4answers
574 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 ...
4
votes
1answer
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
678 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
105 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
307 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
0answers
174 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
2answers
88 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 ...
3
votes
2answers
183 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
467 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
593 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
461 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
327 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
203 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 ...
2
votes
1answer
44 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
362 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 ...
2
votes
2answers
1k 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
1k 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
540 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
269 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 ...
1
vote
3answers
139 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
127 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
1k 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
351 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
47 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
93 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
94 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
175 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
400 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
2answers
57 views

How do you convert SRTM HGT elevations from WGS84 into meters above sea level?

I am building a JavaScript script that reads binary HGT files - as generated by the SRTM - and converts the data into bitmaps viewable in your browser. You can try out the script and view the source ...
1
vote
0answers
73 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
0answers
82 views

Efficient computation of path profile with Numpy and GDAL

I have numpy array with SRTM elevation data and I need calculate path profiles - vectors with elevation data from one point (transmitter) to every points of my map. Here's my current solution: def ...
1
vote
0answers
102 views

What is most suitable DEM to delineate watershed (from spot height, ASTER and SRTM)?

I have three DEMs of our country which are spot height DEM, SRTM DEM and ASTER DEM. SRTM has 90m resolution and ASTER has 30m resolution. My supervisor told me to delineate watershed using these ...
1
vote
0answers
94 views

How to convert DTED Level 1 into SRTM DTED

We have a GIS tool that handles only SRTM DTED level 1 terrain files. SRTM level 1 terrain files are limited to 60 deg lat. So I need to fill up the gap from 60 lat up to 90 deg lat. I have DTED ...
0
votes
1answer
2k views

How can I convert SRTM data to DEM or DTED?

i am working on a project which is not commercial and i need some digital elevation data for visualization. in net i have found a link and i have downloaded .asc data from following link.. SRTM Data ...
0
votes
1answer
361 views

How to transform a DEM to a cartesian coordinate system?

I am using the script r.inund.fluv. I run the script with all the required parameters and it produced a lot or errors. I emailed the author of the script and he said that "I think you are not ...
0
votes
2answers
282 views

Why is this SRTM TIFF not visible in GRASS GIS 6.4.3?

I want to use interpolated SRTM data for Germany to generate an STL terrain map for use in a CFD application. My SRTM data comes from the OpenDEM project. SRTM data normally has voids, but this data ...
0
votes
1answer
85 views

Gdal_polygonize: How to filter pixels above a given value (elevation)?

Given a topographic GIS raster of one country: Given an elevation threshold n = 50 (meters) How to polygonize pixels when z >= n ? gdal_polygonize.py is not clear on this point. It states This ...
0
votes
1answer
6 views

How to determine stream elevation points from SRTM raster with stream lines vector?

I should determine elevation points of some streams. I have SRTM raster and stream vectors. Which tools can solve this problem in ArcGIS 9.3? Anybody can write me a workflow how to do this task? ...
0
votes
1answer
63 views

Importing SRTM Data into Grass

I am having issues importing an SRTM HGT file into Grass. I first made a new location as the instructions from this Grass Newsletter Tutorial states. I then went to the download site and downloaded ...