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

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What is the source of horizontal and vertical striping in USGS DEMs?

When processing 30m and 10m DEM data downloaded through the National Map Viewer from the National Elevation Dataset, we noticed horizontal and vertical striping not only in the produced results, but ...
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46 views

Using Arcpy, how can I determine min and max elevation from a raster DEM layer within my current extent?

Using Arcpy, how can I determine min and max elevation from a raster DEM layer within my current extent? I'm currently using Data Driven Pages to centre the layout on each feature extent. I need to ...
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23 views

Has anyone used ArcGIS for 'automatically' detecting lineaments from a high-resolution (1m) DEM?

I have a set of DEM's produced from LIDAR data. I am wondering if anyone is familiar with or knew of any published research papers which looked at (semi-)automatically detecting lineaments /or ...
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32 views

How to handle “illegal data type (Float64)” error when trying to convert .tif to .bil?

Each time I try to convert (in QGIS 2.2) an elevation model from .tif to .bil format a get this error: ERROR 1: Attempt to create ESRI .hdr labelled dataset with an illegal data type (Float64). ...
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16 views

Negative Topographic Index Values

I am getting negative topographic index wetness values in SAGA GIS - anyone else every get this? Not all negative values, but the minimum of the TWI range is negative for some steep watersheds we are ...
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37 views

Topographic Index - Why is upslope contributing area divided by downslope contour width and not upslope contour width?

In the Topographic Index calculation, a is the upslope contributing area per unit contour length. Is the "unit contour length" calculated from examining the contour widths of the downslope cells that ...
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18 views

Height value incrases

Please is it possible to increase the Z-values of ground control points in aerial triangulation in order for breaklines which have being floating to take the exact boundaries of the features they ...
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12 views

Manipulating Interpolation Outputs

I would like to clip the edges of my interpolation output to cover only a specific Local Study Area and also combine the output with a DEM to create a spatially defined 3D model in ArcGIS 10.1. Two ...
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52 views

How can I create a constant slope DEM?

I wanted to create a DEM of constant slope say 1/3000. How can I proceed in ArcGIS 9.3? The area may be 1000m x 1000m or any other as per convenience.
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43 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 ...
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48 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 ...
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66 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). ...
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33 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 ...
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35 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. ...
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3answers
68 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 ...
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2answers
28 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 ...
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52 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 ...
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37 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 ...
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52 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 ...
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66 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 ...
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36 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 ...
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78 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 ...
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27 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 ...
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3answers
170 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 ...
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41 views

How to determine 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, ...
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36 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 ...
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32 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 ...
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2answers
67 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 ...
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49 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 ...
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2answers
91 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 ...
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30 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 ...
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36 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.
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50 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 ?
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33 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? ...
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55 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 ...
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36 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 ...
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123 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 ...
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36 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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31 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, ...
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23 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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2answers
77 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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16 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 ...
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20 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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37 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 ...
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54 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. ...
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15 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 ...
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126 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 ...
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23 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 ...
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1answer
71 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 ...
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44 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 ...