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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3
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0answers
26 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 to the Arcgis Help 10.2 "Converting ...
2
votes
2answers
44 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
1answer
80 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 ...
2
votes
1answer
131 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 ...
1
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1answer
44 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 ...
3
votes
0answers
31 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 ...
3
votes
2answers
86 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 ...
1
vote
1answer
21 views

DEM error when trying to do topographic correction in GRASS

I'm new to GRASS gis and I'm trying to do a topographic correction (i.topo.corr) of 9 ASTER bands using SRTM dem. I keep getting this error message: ERROR: Illumination model is of CELL type Is ...
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0answers
54 views

NASA SRTM: precipitous contour lines in TileMill

I was trying to make a nice looking print map of Bali (Indonesia) in TileMill. After creating a terrain layer (using this walkthrough) I noticed that the island's coastline was precipitous. Is ...
1
vote
1answer
64 views

Using gdalwarp with multiple elevation models

I'm trying to use gdal_warp to slice and convert some SRTM data. The data I'm interested in are in S30E152.hgt and S30E153.hgt. What I'd like to do is: Convert these DEM files from EPSG:4326 to ...
3
votes
2answers
49 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 ...
2
votes
0answers
30 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 ...
0
votes
0answers
28 views

How to smooth raster data? [duplicate]

I want to print a map of an island based on SRTM data but the basic raster layer looks pixelated especially at the transition to the ocean. Is there a way to smooth it?
1
vote
0answers
60 views

SRTM elevation data question

I have a question concerning the SRTM elevation data (http://srtm.usgs.gov/). As a little thought experiment, assume I want to build a 3D model of the earth's surface as a point cloud. The earth's ...
1
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0answers
31 views

Converting DEM data to height information in meters using QGIS? [duplicate]

I'm relatively new with QGIS and currently I'm working with ASTER and SRTM DEMs. The goal is to create vector heightcontours with labeling in meter. Can you tell me how I can convert the grayband ...
0
votes
0answers
113 views

How to import SRTM data for the whole planet into TileMill

I need to get SRTM elevation data for the whole planet into TileMill. I already walked through the instructions on Steve Bennett's blog and it worked fine for small areas. The problem is now that for ...
0
votes
1answer
106 views

cut square from geotiff

i want to make a 3d modell out of the mount everest and some other mountains. what i need therefore is a 14km² square around the peak from the mountain. so basically i use qgis to extract the area ...
0
votes
1answer
85 views

gdalbuildvrt error when mosaicking SRTM data with different NoData values

I'm attempting to mosaic together 9 SRTM tiles downloaded from CGIAR to produce a DEM of Borneo. I'm using: gdalbuildvrt Borneo.vrt BorneoSRTM/*.tif where BorneoSRTM contains the 9 tif files to be ...
0
votes
1answer
59 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? ...
4
votes
2answers
124 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 ...
1
vote
2answers
247 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 ...
6
votes
5answers
330 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 ...
2
votes
0answers
130 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 ...
2
votes
1answer
62 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 ...
0
votes
1answer
120 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 ...
1
vote
1answer
80 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
3answers
194 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
1answer
142 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
139 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
0answers
98 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 ...
0
votes
2answers
523 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 ...
1
vote
2answers
203 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 ...
0
votes
1answer
157 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 ...
1
vote
0answers
138 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 ...
4
votes
1answer
119 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? ...
3
votes
1answer
568 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
252 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
403 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
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
0answers
111 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 ...
5
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 ...
3
votes
1answer
459 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 ...
5
votes
1answer
365 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.
1
vote
1answer
434 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
218 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 ...
4
votes
0answers
228 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 ...
1
vote
1answer
486 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 ...
4
votes
4answers
735 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 ...
3
votes
1answer
537 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
678 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 ...