Digital Elevation Model (DEM), which could be a Digital Terrain Model (DTM) or a Digital Surface Model (DSM).

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2
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1answer
419 views

Compare two Digital Elevation Model (DEM)

I would like to know what's the best method(s) to compare two DEMs without using any GUI soft like QGIS or ArcGIS. I'd like to do it in Python or C++, with GDAL or other similar lib. Does calculating ...
2
votes
4answers
850 views

What could cause garbage hillshade output

I've used Hillshade successfully in the past, but for this DEM I keep getting a weird output. It's a 30-meter TIFF downloaded from the National Elevation Dataset. And this is what the output looks ...
0
votes
1answer
134 views

Correlation and terrain databases [duplicate]

I would like to know what kind of computation I could perform on a terrain database. I'm making terrain for VBS2 from raw data (shp files and DTM Elevation files) and then I'd like to be able to check ...
1
vote
2answers
3k 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 ...
0
votes
1answer
601 views

How to calculate surface area of highland region using DEM with ArcGIS (ArcEditor)? [duplicate]

Am shyaka from Rwanda. I use GIS tools and have all required data to perform or calculate surface area from the polygons that have been given by GPS (Trimble) with ArcPad 8. I originate from a high ...
3
votes
2answers
471 views

Where to download 10m (1/3 arc-second) DEMs?

I'm looking for some of the 10m DEM to fill in the white Quad areas. Do you know where of can I find them? These 10 DEMs we have are actually coming from the NRCS Geospatial Dataway. I believe they ...
4
votes
2answers
288 views

Autocorrelated DEM with QGIS or Grass

I was wondering if there is a way to make an Autocorrelated DEM within QGIS or Grass. I am looking to do this with stereo aerial photography. I am able to do this with a number of COTS tools, but I ...
1
vote
2answers
1k views

What software is available on OSX for working with DEMs?

I have several adjacent DEM files and would like to combine them into a mosaic and then export to DEM and TXT. I know a Windows solution is to use MICRODEM but before installing Windows 7 I would like ...
1
vote
1answer
232 views

How to apply DEM elevation adjustment parameters?

I have a nice DEM, created from UAV data, which I want to process further in QGIS, my platform of first choice. In order to represent the evelation of each pixel correctly, I have to adjust the ...
3
votes
1answer
611 views

“Topo to Raster” tool for QGIS?

is there any analogue of the ArcGIS "topo to raster" tool in QGIS? I need to creates surfaces from shp for some cases from points and for some from lines and this instrument is very convenient.
1
vote
2answers
127 views

viewshed analysis for observers wearing visors?

I'm starting with a DEM, and looking to identify every point that can be directly "seen" from any point in a particular polygon on an overlaid layer defining an area on that DEM - like any other ...
3
votes
0answers
46 views

Adjacent DEM files have narrow triangular gaps when joined

Newbie here. I've downloaded several DEM files from GeoCommunity which correspond to adjacent regions. When I join them together to form a larger relief map there are triangular 'gaps' on all four ...
4
votes
2answers
630 views

Retrieving average building height in urban areas

I am looking for a way to collect data on the height profile of some cities over time. I don't need to produce a detailed 3D reconstruction of cities, nor do I need to detect and measure individual ...
1
vote
2answers
1k views

Elevation difference map using two DEM

I am studying glacier mass balance and have ASTER and SRTM DEMs. I want to make an elevation/volume change image such that it graphically represents changes in elevation difference in various parts of ...
0
votes
0answers
51 views

How to extract elevation data from DEM along a polyline [duplicate]

I've been trying to use qGIS to extract and save as an attribute the data elevation along a line, knowing that something similar is available in ArcGIS using the Spatial Analysis tool. So far, ...
3
votes
2answers
399 views

Create hachures from DEM in ArcGIS 10.1

I have created contour lines from DEM and now I need to create hachures/bergstrich for them. I believe that spatial analyst should solve this, but I'm not used to it and I didint found any similar ...
5
votes
3answers
1k views

How to drape a simple jpeg image over dem of some area?

How can we drape a simple jpeg image which doesnot have any geo referencing information over the digital elevation model in order to visualize it in 3D in QGIS?
3
votes
1answer
656 views

Calculating mean upslope aspect from each cell in DEM using Python?

I am trying to write a python script to calculate the mean aspect upslope from each cell in a DEM. I have the general workflow down, but my final output is restricted to angles between 0 and 90 ...
3
votes
1answer
94 views

What function should I use to assess the degree of elevational change (rocky cliffs etc.) of a DEM?

I have a DEM of my research area and I want to assess how the topography/elevation changes. I am specifically looking to see what areas may be good suitable bat-roosting habitat so I am trying to ...
2
votes
1answer
174 views

filter / generalize elevation points on the basis of some conditions

I wanted to generalize many elevation points in a rectangular area (about 700 square km). I need to take about 3 points for square km. These points must satisfy some conditions: One of these ...
0
votes
1answer
3k views

Calculate maximum and minimum elevation for a polygon layer from a DEM [duplicate]

I have a polygon layer and would like to know the min and max elevation within each polygon. My elevation layer is a digital elevation model. I'm not quite sure how to extract that information. I am ...
3
votes
1answer
355 views

Hydro-Enforced/surface constraint DEM Creation using GRASS/QGIS

I am wondering if there is a way to create a hydro-breakline enforced DEM by means of any open source solution? I am able to create a DEM from Lidar data using GRASS, but would like to enforce some ...
5
votes
2answers
691 views

How to extract coordinates & elevations of boundary cells of DEM?

I am using a 50mx50m grid irregular shaped DEM file. I have to work on the boundary conditions. How do i extract the cell locations ( in x,y coordinate ) along the boundary edge and consequently ...
3
votes
1answer
212 views

ArcGIS Raster Symbology - Break contour at 0

In ArcGIS 10, how can I break raster symbology (stretched) at a particular value (i.e. 0). For example, I have a DEM representing both topography and bathymetry and I want a break at the 0 m contour ...
3
votes
1answer
703 views

How to increase resolution of DEM rasters?

Thanks to the fine folks here at the GIS SE, I have managed to batch process a load of ASC files into raster hillshade TIFs. However, while they look fine on screen, when printed they are very ...
1
vote
2answers
205 views

Put color for raster data(aspect.tif) on QGIS1.8.0

I create aspect.tif from DEM file. I could put the values(0 to 360)from contrast enhancement. I could set color from color map(freakout or Pseudocolor). In here, the data is shown by only 4 colors. I ...
1
vote
0answers
79 views

Is there any accuracy difference between standard DTM editing tools like DT Master and automatic removal of artefacts using ERDAS?

I would like to know whether there is any accuracy difference while editing DTM points using standard photogrammetry software like Inpho DT Master and automatics removal of artefacts in ERDAS imagine. ...
1
vote
1answer
165 views

How to remove terracing from Civil3D GeoTIFF export?

I've received a GeoTIFF DEM that was exported from Civil3D and at every contour there is a distinct terrace created when I process an aspect or slope in QGIS with the GRASS plugins. I've looked ...
3
votes
5answers
2k views

Batch processing DEM rasters in QGIS/GDAL

I am attempting to add relief shading to map using .asc raster files, following this tutorial. It works well, but I have only tried it on single tile of raster data which is 20x20km. I want to ...
1
vote
2answers
982 views

Import Civil 3D DEM to ArcMap or QGIS

I have some survey data exported from Civil 3D in both dtm and dem formats. I thought the I would be able to use the dem more easily, but I think the format is different from a USGS DEM. Is it ...
2
votes
0answers
72 views

Arcpy: Counting number of segments where altitude rises or decreases based on DEM?

I have a DEM of Sudety mountains and linear .shp with several hiking paths. I'm trying solve one problem: How to make a script based on input DEM and input line shapes that would count number of ...
8
votes
1answer
576 views

How to generate a DEM from isolines and spot heights?

I have two shape files containing height information of a certain area and I need to create a raster DEM with GRASS using them. file 1 consists of height information in contours (isolines) file 2 ...
2
votes
2answers
215 views

Creating basic DEM file with flat geometry in ArcGIS Desktop?

I want to create a basic DEM file in .ascii format which will just be a rectangular grid and with no slope i.e same elevation at every cell. Please provide information on how to achieve this. I am ...
3
votes
4answers
4k views

Open source tool to view DTED and DEM raster-data

I am new to GIS field. Is there any open source GIS tool to view DTED and DEM tiff-files? Update 1 I have some DTED files and DEM files. I want to open and see those files using some open source GIS ...
6
votes
1answer
936 views

How to calculate te area between contour lines on a DEM with QGIS 1.8?

Does anyone know how to calculate the area in km² for each altitudinal band (between 100 and 200, 200 and 300...) based on a DEM? I added the contour lines with a distance of 100 metres but could not ...
2
votes
1answer
487 views

Orthogonal Height Profile along line (sextante -> v.segment, r.profile?)

While trying to find a way to find "valleys/ridges" within a DEM, I'd like to know if there are tools, plugins or "methods" known or available to automatically generate height profiles along a given ...
5
votes
1answer
190 views

Calc bottomline of valleys

Which way do I calculate bottomlines of valleys or even more preceise: which way do I "find" valleys (for example suggested tectonic faults). Sample below shows a height profile (profile from line) ...
12
votes
2answers
665 views

PostGIS interpolation / triangulation options

I'm looking for an open source workflow to automate DEM construction. We have a series of sites that fall within a LIDAR dataset. We want to create site specific DEM's for each site, and we're ...
-4
votes
1answer
125 views

QGIS to support hydraulic engineering projects [closed]

What is DTM in hydraulic projects? and what is application area of QGIS ?
5
votes
2answers
2k views

Exporting DEM-derived rasters to CSV from QGIS?

I have been able to import into QGIS a set of raster topographic maps and the associated DEM raster maps. It registered the two for me. From there I have calculated the associated slope raster map. ...
3
votes
1answer
91 views

Is it possible to create DEMs from ORT format in QGIS?

I recently requested DEMs for my area of interest. The data has however arrived in ORT file format - how do I create DEMs from this data in QGIS? When I open the files in Notepad there are three ...
4
votes
1answer
289 views

How to extract most probable flow line from multiple lines?

I have to apply uncertainty principle to computing flow accumulation using Monte Carlo method. I generate raster with random numbers which represents mistakes in creating DEM. Then I apply those ...
8
votes
5answers
332 views

How to ensure uniform colour for DEMs?

This is a silly question, but one I've been trying to figure out for a while. I have two Aster DEM tiles, one next to the other. How do I ensure uniform colour for both?
3
votes
1answer
569 views

Where can DEM data for all of British Columbia be found?

Is there a website or server from which a DEM covering all of BC can be downloaded - preferably at 1:50K scale? GeoBase has tiles for 1:50K and 1:250K, but they do not provide it as a mosaic. It's ...
3
votes
2answers
716 views

Can I sell maps produced from ASTER Global DEM V2 data?

I don't quite understand the term-of-use of ASTER Global DEM V2 data: By selecting 'Submit', I agree to the following: -I agree to redistribute the ASTER GDEM only to individuals within my ...
9
votes
3answers
2k views

Create DEM from stereo pairs?

Does ArcGIS Desktop or any of its native extensions allow me to create DEMs from stereo pairs (acquired by satellite, GeoEye 1)? If the answer is a clear no, brownie points will go to an answer that ...
3
votes
2answers
831 views

gdal doesn´t support my *xyz file

I have just exported a tif DEM to XYZ format with SAGA GIS. When I check this with gdalinfo it states that the format is unsupported? Seeing as I converted this with saga gis which used gdal I find ...
2
votes
1answer
1k views

Problem merging two rasters in Qgis

I have two rasters in Geotiff, same CRS. I tried to merge them and I have this error code ERROR 4: `C:/Anita_Tepoztln/Rasters/e142.tif' does not exist in the file system, and is not recognised as a ...
1
vote
3answers
1k views

How To find the Catchment Area for a Dam?

I have a DEM of my study area, and polyline shapefile of the Dams in that area. I have run the standard Hydrology tools on it( Fill, Flow Direction & Flow Accumulation). I know that you can ...
2
votes
2answers
281 views

Driver Error : DTM to Raster using GDAL_GRID

I am looking to interpolate a DTM (eventually over 4,000 DTMs) that is in a personal geodatabase format. I would like to do this in as few step as possible, eventually writing a batch script to do ...