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

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2answers
112 views

Contours from DEM with human features

I am rather new at GIS and I would like to have some guidance on what follows. I have some DEMs derived from LiDAR data. These DEMs contain building and other human features (e.g., roads). I was ...
0
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2answers
126 views

Where is it Possible to Find DTED0 Set?

As I understand, DTED0 should be available for free. Yet, I am not able to find any download link. Everything that Google search brings up (eg. http://geoengine.nima.mil) is dead and not working.
2
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0answers
74 views

DTM Extraction/Smoothing in ArcGIS

I have an .las file, intended to be a DTM (bare earth) that I generated from a photogrammetry software package that has come out just a bit too lumpy. I now have the license for that software tied up ...
2
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1answer
42 views

Is there a way to clip a polygon layer according to DEM elevation?

I have a polygon layer on top of a DEM. Is there a way to clip the polygon layer according to elevation, ie the clipped result being only those areas of the polygon layer between x and y altitude? ...
1
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1answer
127 views

Reprojecting a raster DEM from meters to feet using QGIS?

Is there a tool in QGIS that does the same as reprojecting a raster DEM from meters to feet as in ArcGIS's 3D Analyst > Raster Math > Times ?
4
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2answers
514 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 ...
7
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1answer
936 views

Partially updating raster (DEM)?

How to update an .img DEM in ArcView 9.3? I do have DEM which need to be updated only if few parts. The area to be updated has been produced in separate DEM with Spline Interpolation with Barriers. ...
1
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1answer
252 views

Where can I obtain 3D data for Singapore?

I am looking for providers of 3D maps/models of Singapore. This might be either from photogrammetry/laser techniques or based on a DEM + building footprints/landuse with a height attribute. Is any ...
0
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1answer
188 views

Hillshade is block grey ArcGIS

So I am trying to create a hillshade on my DEM because I need to be able to distinguish features which I can't do in its current state (see picture). However, when I add the hillshade, it adds a block ...
3
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2answers
188 views

Merging DEMs of different grid size

I'm trying to merge two grids with different cell size. One has a cell size of 10m and the other 50m. The 10m one covers a subarea of the 50m one. I know that the most accurate one is the 10m one and ...
1
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0answers
39 views

Using GeoBrain WCS4DEM in QGIS?

I added the GeoBrain WCS server to the server list: http://geobrain.laits.gmu.edu/cgi-bin/gbwcs-dem?version=1.0.0& I connect to the server and get a list of layers. I select the first one listed ...
4
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2answers
123 views

How to query DEM elevation values in a web application based on cursor/click point location?

I work for a city government that has LiDAR derived DEM rasters which we would like to make accessible to other departments in the city. The problem is that many departments don't have anyone with ...
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0answers
56 views

QGIS 2.2. raster color ramp

I have just upgraded from QGIS 1.8 to QGIS 2.2 and I am missing very much 1-band raster color ramp plugin that I had easily colorized my DEMs by using pre made color brewer such as DEM screen or DEM ...
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0answers
61 views

passing tif image as input to openlayers code (wps implementation)

how to pass dem(tif) or raster layer as input to the openlayers ... //OpenLayers.ProxyHost = 'proxy.cgi?url='; OpenLayers.ProxyHost = "/cgi-bin/proxy.cgi?url="; //OpenLayers.ProxyHost = ''; var map, ...
0
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0answers
36 views

Finding normal vector to DEM

I have a DEM grid (Surfer, or whatever format) and an x,y position on that grid. I also have a series of depths from the surface. I need to calculate, for each depth, the x,y,z of the projected ...
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0answers
57 views

How to make DTM Qgis-grass

Good evening, I need help. Should I create a dtm of an area in the province of Vicenza. It 's the first time I try, I tried the tutorials on the Internet but I could not understand how to do it. Could ...
10
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2answers
2k views

What software to use for making digital elevation models from UAV aerial imagery?

I have a an unmanned aerial vehicle (UAV, also called a drone) and would like to use it to create a digital elevation model and orthomosaic over a smaller area (10 km2). My platform will be able to ...
2
votes
1answer
59 views

How to apply Log Transform to Flow Accumulation?

I have run a flow accumulation for a DEM that I'm working with. I'm trying to apply a log transform because I've heard it could give a better visual representation. How would I go about doing this ...
0
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0answers
32 views

Things to consider while and after merging DEM-Tiles?

In some tutorials it is said that after merging you should stretch the “histogram to full dataset” (also mentioned in the QGIS Training Manual). Is there anything else you would suggest doing after ...
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1answer
116 views

Importing a DEM in ASCII format into Arcmap - Projection issues [closed]

I've been trying for the last couple of days to import an ascii grid file into Arcmap. However, I'm really battling to project the data. Can anyone please assist? It would be very much appreciated. ...
0
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0answers
87 views

Why does merge/mosaic four DEMs into one give ERROR 01042?

I'm unable to merge 4 dems into one using ArcGIS Home 10.2. Raster Calculator, adding them, gives me the error: RuntimeError: ERROR 010422: Error in processing the environment mask. I created a ...
3
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4answers
254 views

How to clean up contours?

I have .dxf file with contour lines representing elevation. But this contours are too "ugly" and elevation model looks just bad. As you can see on image, contours are not continuous... Is there any ...
4
votes
1answer
111 views

Interpolate Temperature Using DEM

I want to "co-interpolate" temperature with DEM. I have SRTM 90m aggregated to 1km and I want to "co-interpolate" my DEM with points with temperature data. How do I do this? I am using ArcGIS 10.
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0answers
19 views

Calculating std dev for ruggedness using QGIS?

I have a DEM raster image and a vector layer with 200+ grids. Using QGIS, I got the terrain ruggedness index for the DEM layer. Now, I want the std dev (i.e. variation in ruggedness) for each of the ...
8
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2answers
2k views

Workflow for determining stream gradient?

As far as data goes, I'm working with NHD .shp files, 10m DEMs, and some LIDAR data. My goal is to determine gradient for 100m segments of a network of streams. I'm already able to do this, but I ...
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1answer
45 views

Combining several rasters before r.surf.contour?

I have been trying to generate an elevation model from contour lines using first v.to.rast.attr and then r.surf.contour. Generally, it works pretty well, execpt for one issue. My data contains a lot ...
7
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2answers
2k views

How to build an artificial 'dam' across a river?

I have a DEM. Created all files related to watershed including accumulation, direction, streams etc... I'm stuck creating a dam. I request you to please let me know how to build an artificial 'dam' ...
2
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1answer
571 views

How do I run the nvis tool in QGIS GRASS?

I am trying to follow this workflow: [How to generate a DEM from a countour Shapefile?] and it's running fine, and when I hit view output or view results I end up with a flat raster with shading ...
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1answer
51 views

Make a Ground Mask raster with the Greater Than tool (DEMs are generated from LiDAR)

I'm trying to see if I can replicate the Esri solar suitability site example from this article. I fail on the creation of the binary ground raster. I have made a Bare Earth raster from LiDAR ground ...
2
votes
1answer
426 views

Is there a way to convert GeoTIFF to DEM?

Simple enough question. The NASA Aster data comes in GeoTIFF format, but the tool I'm using (Sketchup) only accepts DEM. Is there a way to convert? I did a lot of searching, and only found the ...
7
votes
2answers
2k views

Can shaded relief be “blended” with DEM colour ramp in ArcGIS to produce a more visually dramatic result?

Not being able to use true transparencies with ArcGIS colour ramps where only solid colours are allowed has me always wondering about how to improve the look of the surface in my maps without ...
0
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0answers
81 views

Iceland base data - dem, hydro etc

I am looking for elevation data for Iceland. Specifically a higher res dem (30m) and some good hydrography, glaciers etc. Any suggestions for a good data source?
3
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1answer
85 views

Add Z and M values to stream network produced from DEM

I created a stream network from an existing DEM. My ultimate project goal is to be able to select a river from my stream network and use the 3D analyst to generate stream profile (Elevation by ...
6
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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 ...
1
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2answers
813 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
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0answers
55 views

Digital Elevation Model Fusion

I want to fuse Digital elevation Models extracted from Carto-1 satellite. I already extracted DEMs & tried few algorithms in Matlab. Unfortunately as they are not Georeferenced i am not getting ...
0
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1answer
134 views

How to remove pixel values below 0 in Digital Elevation Model in ArcGIS?

I made a DEM layer from LAS file (LiDAR).Now for showing a map I have a map like the image below! I wonder how can I remove black area? They have the value -2 to 16! How is possible to set the value ...
0
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1answer
84 views

Viewshed calculation using SQL

Can i calculate viewshed in MS-SQL server? Viewshed analysis is Raster operation. I have elevation value vector observation as point vectors. Are there any methods to calculate Viewshed (using ...
1
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1answer
109 views

Find minimum elevation along a polyline and return xy or point?

Using ArcGIS 10.1 and Python IDLE 2.7.2... I'm trying to find the minimum value of a polyline with a raster layer and turn that LOCATION into a point. I put everything together in model builder, but ...
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0answers
39 views

How do I split a DEM at a certain elevation?

I have a DEM that includes bathymetry and terrain elevation and I would like to split it at the coastline. Ideally, I would end up with one tif that's land and one tif that's bathymetry. I have ...
1
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3answers
132 views

Calculate Number Of Pixels Visible From Pixel

I am looking for a way in which to take an input DEM and create an output raster whose pixel's value is the count of pixels "visible" from that location. I use ArcGIS with Spatial Analyst, but also ...
0
votes
0answers
127 views

DEM/DSM from contour lines and slopes

I want to create a DEM with as much detail as possible. The problem is, that the area contains several (manmade) slopes. I got contour lines and lines that mark the location of the slopes, but no ...
3
votes
1answer
150 views

How to give elevation information to a polygon feature class using existing TIN file ? (geological mapping)

I'm an ArcGIS 10.1 user. My issue: I have a printed form of a map which depicts geological bodies being surface rock occurence. Additionaly, there are elevation contour lines. I digitized the map by ...
1
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0answers
127 views

What steps does SAGA GIS take when calculating Topographic Wetness, specifically when handling depression filled (by ArcMap) DEM

I am a grad student involved with hydrological modeling. In the model I work on, we are calculating the Topographic Index (TI; without transmissivity - or set to 1) using Quinn's MFD algorithm. We do ...
1
vote
1answer
373 views

QGIS DEM (Terrain models) Mode Slope creates wrong data [duplicate]

I have a DEM raster file downloaded from the USGS site. The file can be downloaded here. I am trying to create a slope raster in percent with the DEM tool in QGIS. The GDAL command is the following: ...
3
votes
2answers
379 views

How to create 3D water depth with ArcScene?

I was trying to visualize flood depth in 3D using ArcScene. What I had for this purposes are: high-resolution DTM of the valley orthophoto and Raster with flood depth information. I have draped ...
6
votes
2answers
896 views

FOSS method to split raster into smaller chunks

I have a raster (USGS DEM actually) and I need to split it up into smaller chunks like the image below shows. That was accomplished in ArcGIS 10.0 using the Split Raster tool. I would like a FOSS ...
2
votes
2answers
76 views

What are the ways we can control the quality of a DTM?

I imagine that for DTM obtained from Stereoscopic procedures or interpolation from a set of topographic points a comparaison with the original data can help, but what for DTM obtained from Remote ...
2
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0answers
54 views

Define uphill side of roads and buildings

I have a big raster of a mountain region and I need to extract the uphill side of roads and buildings, from these elements to the pick of mountains. For a road I know the uphill side changes in ...
16
votes
5answers
9k views

Is it possible to make a DEM from contours in QGIS?

Is it possible to make a DEM from contours in QGIS? I have a shp file (contours) and their heights, can I use QGIS for produce a DEM without using GRASS? I find this creating a dem from contours but ...