For questions about Digital Elevation Models (DEM), Digital Terrain Models (DTM) and Digital Surface Models (DSM)

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3
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1answer
228 views

Creating constant slope DEM using ArcGIS Desktop?

I wanted to create a DEM of constant slope say 1/3000. How can I proceed in ArcGIS Desktop 9.3? The area may be 1000m x 1000m or any other as per convenience.
0
votes
1answer
587 views

DXF (points and lines) in QGIS - Doesnt import z coordinates

Trying to get to grips with QGIS, coming from a Mapinfo and Civil3D background. I have a DXF file with points (X,Y,Z) and lines. I want to open this in QGIS and use the interpolate plugin to create ...
1
vote
1answer
208 views

Extracting DEM from imagery using ArcGIS for Desktop?

I'm using ArcGIS for Desktop and I'd like to know how can I extract the elevation model from a imagery of photos. I have the have each image (jpg) geo referenced. After, I don't know what tool may use ...
2
votes
1answer
481 views

Obtaining average value around polygon in raster for different cross sections?

I have elevation data in a raster, river (blue line) and the flooded area (black polygon) as shown in the image below: I want to find the water depth in the flooded area (inside the black polygon). ...
0
votes
1answer
86 views

What dem data are Flex Viewers using to create elevation profiles?

I asked a similar question a year or two ago here: Can Elevation Profile data in Arc's Flex Viewer 3.0 be exported? which appears to not have an answer. Another question regarding the Flex Viewer (3....
0
votes
1answer
69 views

Viewshed over Multiple DEM Models Possible?

I finally got the viewshed working correctly over one DEM model. However, I am wondering is it possible to do the viewshed over multiple DEMs? E.g. A Multiple County Viewshed based off one point. ...
1
vote
3answers
1k views

ArcMap - Making DEM using GPS vector data [closed]

I am new to GIS and GPS. I am going to make a digital elevation model of my school's campus using a trimble gps unit. I know the accuracy is not the best but it is just for a school project. My ...
0
votes
2answers
350 views

r.topidx error: required parameter output not set

I'm calling GRASS r.topidx from QGIS 2.2.0. I can get other tools to work on the DTM, for example r.watershed. But r.topidx I get the Oops message: Oooops! The following output layers could not be ...
5
votes
1answer
300 views

How can I get the profile graph on ArcMap to display specific points?

I currently have 2 layers: 1) DEM of existing terrain 2) Polygon in vector format of future water retention basin I need to draw cross sections across this basin for eventual cut and fill calcs. I ...
0
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0answers
280 views

How to create .dem file in QGIS?

I have an elevation data in .asc file, but need to convert it to .dem file to later use in COMSOL. However, in Raster--> Analyzes-->DEM I got just error message: ERROR 1: DEM Default Setup: Importing ...
2
votes
1answer
2k views

Dem file in .adf format, while .tiff is needed

I would like to use this standalone tool to get different kind of Dem visualizations (http://iaps.zrc-sazu.si/en/svf#v). I see that the program accept only .tiff DEM. Now, the DEMs I got are not in ...
1
vote
2answers
382 views

Retrieve Elevation from Color in Raster DEM

This might turn out to be a newbie question, and that would be because I'm fairly new to GIS work, but extensive online searching, asking associates with some basic GIS knowledge and hours in various ...
0
votes
1answer
718 views

Best Resampling Method for DEM reprojection in QGis

I need to reproject a DEM (aster file) in order to have the same CRS as all my other project data - I have different SHP for the same DEM's location but they have a different CRS. Which resampling ...
4
votes
1answer
764 views

How to obtain a DTM/DEM from DSM

I need to obtain a grid of bare ground elevation (removing all edifices, trees, roads and man-made elements) for quantitative geomorphological analysis from a high resolution (1 m) DSM obtained by ...
1
vote
1answer
81 views

What is a better idea for modelling a fault plane than as TIN? [duplicate]

I am working on a project which runs on ArcGIS platform using VB.NET. It is to model a sub-surface fault plane (currently a plane rectangular model with some dip) and then to find required distances ...
4
votes
3answers
1k views

Las to bare-earth DEM: average points spacing and cell size

I am using ArcGIS 10.1 to generate a DEM (bare earth) from LAS dataset. To accomplish this, I use 'Las Dataset to Raster' tool as described in Esri website. I have read here and there in the web that ...
6
votes
3answers
2k views

Determining bare earth from unclassified LAS file?

I have data in LAS format with RGB values created from Aerial photogrammetry using a UAV. I am trying to find a solution to extract the bare earth to create my DTM from the DSM. I have tried SAGA, ...
0
votes
0answers
219 views

Advice on how to present a cross section

So, I'll try to best explain what I want to do. I have a DEM of a volcano (only showing half the DEM in pictures below) and I have identified a lava flow that I would like to make a cross section/...
1
vote
1answer
259 views

Fixing Hole in DEM?

I have what looks like a hole in my DEM! I don't think it is affecting my calculations, but either way, I would quite like to correct it. Does anybody have any idea how? Please see the attached ...
1
vote
2answers
748 views

DEM mosaic: gaps

I have generated DEMs (bare earth) from Lidar data. For computational reasons, I have processed via ArcGis the lidar files in chunks, so I came up with different single DEMs. After, I used "Mosaic to ...
1
vote
1answer
430 views

QGIS Slope Classification Issues

I am very new to QGIS for the primary purpose of creating a slopes layer so we know where slopes are above 15% or 20% or whatever we finally decide. I have used our DEM to create a slope geotif and ...
1
vote
2answers
160 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 ...
2
votes
0answers
381 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 ...
0
votes
2answers
2k 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.
1
vote
1answer
798 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 ?
2
votes
2answers
212 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? ...
0
votes
3answers
779 views

Import DEM into PostGIS for QGIS

I'm a complete GIS newbie so sorry if I'm using the wrong terminology in searching for a solution to this... I'm trying to import a DEM into PostGIS and display it in QGIS. The data is from the EU-DEM ...
1
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0answers
57 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 -...
0
votes
1answer
342 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 ...
0
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0answers
65 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 ...
5
votes
2answers
331 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 ...
0
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0answers
112 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 ...
0
votes
0answers
249 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 ...
1
vote
1answer
458 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. I'...
0
votes
0answers
54 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 ...
3
votes
4answers
2k 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 ...
2
votes
1answer
92 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 ...
2
votes
1answer
3k 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 ...
2
votes
1answer
98 views

Make a ground mask raster with the Greater Than tool

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 ...
3
votes
1answer
480 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 ...
0
votes
1answer
335 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
0answers
98 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 ...
3
votes
1answer
130 views

Very high resolution stereo-imagery

I'm looking for very high resolution stereo imagery to perform a DEM extraction. The only place I can find sample data is http://www.digitalglobe.com/product-samples but the form does not work for me. ...
2
votes
1answer
2k views

Removing pixel values below 0 in Digital Elevation Model in ArcGIS for Desktop?

I made a DEM layer from a .las file (LiDAR). How can I remove the black area which contains negative values? Is it possible to set these values equal zero or null?
14
votes
3answers
604 views

Account for bridge overpasses in a ground DEM to allow for water flow under the overpass

I have a bare earth DEM made from lidar data (A). It works well and has passed all accuracy tests. It is used in storm surge models. The problem we are having is on underpasses. I need to allow water ...
0
votes
1answer
2k views

QGIS 2.2: GDAL Grid (Interpolation) Error

As much as i understand Raster -> Analysis -> Raster (Interpolation) can provide me with a terrain file out of a shape file with a Z coordinate. I select the input and output file and a Z field. It ...
3
votes
1answer
1k views

How to get Drainage Divide and Streams from DTM

Does anyone know how you can get a map like this attached, having the digital terrain model? I'm sorry, but I do not know what is the exact technical term in English for them. I hope you understand ...
1
vote
1answer
708 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 ...
4
votes
2answers
503 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.
1
vote
0answers
57 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 ...