Questions tagged [dem]
For questions about Digital Elevation Models (DEM), Digital Terrain Models (DTM) and Digital Surface Models (DSM)
1,680
questions
0
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1answer
37 views
Manually changing elevation data of DEM using QGIS [duplicate]
I'm looking to do personal modifications to a DEM (Aster global elevation model).
I want to select an rectangular area & reduce its recorded elevation by 20m.
There are other parts on my map I ...
2
votes
1answer
26 views
Indexing RasterStack in for loop
I am trying to calculate canopy height. I have a RasterStack which has 8 rasters in it. The first 7 are DSM; the 8th is DTM. As you see in the function, I need to subtract every DSM with the same DTM. ...
0
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0answers
27 views
Calculating mean of true ground points in every pixel of DEM using ArcGIS Pro
I have a DEM of 12m resolution and true ground points (more than 11,0000 points) to assess this DEM.
I want to take the mean from all points within every pixel using ArcGIS Pro.
How can I do this?
0
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0answers
15 views
Clipping raster error 4
I'm on QGIS 3 and have used the 'AusMap' plugin to upload google maps raster images and a 5m LiDAR DEM. I have created a shapefile (polygon) and now I want to clip the raster files to the extent of ...
0
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0answers
28 views
Raster reprojection from EPGS:4269 to EPSG:4326
I downloaded dem rasters for USA and they use EPSG 4269 CRS. Now, I want to sample raster values (elevation) at some points that use EPGS:4326 CRS.
Do I need to reproject rasters to 4326 before ...
2
votes
1answer
36 views
Get footprint or boundary of LIDAR data
I am using the lidR package in R to manage my ALS data. I was having problems generating DTMs on the edge files of my catalog because the tool lidR::grid_terrain() was doing some interpolation between ...
1
vote
0answers
42 views
Calculating slope between two points
I want to know slope value between two point with lat and long coordinates. I can also get DEM values at lat long location for both points. What should I do next in order to calculate slope?
0
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0answers
18 views
Slope calculation workflow on pixel level
I know I cam calculate slope values based on DEM raster but I want to know how slope is calculated on pixel level. What values are taken into account when calculating slope on one pixel?
Can anybody ...
0
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0answers
16 views
QGIS: creating TIN from raster with a specific point density per m²
I have an elevation data from Laser Scan with 8 points/m2 density. To lower the computation time (and to transfer it to another Software) I want to create a TIN file with density of 0.5 points / mĀ². ...
0
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0answers
14 views
TauDEM flowdircond tool doesn't give an output
I'm using the flowdircond tool from TauDEM to create a hydroDEM. The tool gives an error message when using mpiexec through Windows CMD. When used without mpixec, the tool doesn't give either the ...
2
votes
2answers
28 views
Unit conversion of DEM
I have a 10-m resolution DEM, in the form of a .gdb. The "Value" field is in feet and cannot be edited. I am working with SWAT -- which uses the Band 1/Value field-- and assumes units are in ...
1
vote
1answer
13 views
Feature extraction for sand dunes and hills using DEM
I want to extract only sand dunes, ridges and hills from a DEM.
Note that there are other elevated objects in the DEM as well and on the mountains and ridges that I donāt want.
Is there any way i can ...
0
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0answers
6 views
Overlay Vector Layer on 3D model built from another Vector Layer
I have 2 vector layers. One vector layer has data that I built a 3d model from. I built a choropleth from the other vector layer. I want to overlay the choropleth layer onto the 3d model built from ...
0
votes
1answer
33 views
Failing to download SRTM data from USGS
I was used to download SRTM/DEM data from the following link: https://dds.cr.usgs.gov/srtm/version2_1/SRTM3/
But I'm not being able to download anymore, I don't know the exact causes of that, it was ...
0
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0answers
24 views
Dynamic Slope Calculation on ArcGIS Online Web Application
I have a DEM raster layer in our own GIS portal. It is then included in a web map online from which a web application is created.
I am looking for a way that would allow users to calculate slope by ...
0
votes
0answers
15 views
Classifying DEM base on lowest elevation of stream generated by flow accumulation of same DEM using ArcMap
How do I classify a DEM base on the lowest elevation of a stream (stream generated by flow accumulation of same DEM)?
I want to find those elevation of DEM that are close to the floor of the stream. ...
2
votes
1answer
63 views
Building exaggerated elevation profiles from VRT DEM in QGIS
I have this little challenge, where I need to build an elevation profile from a VRT DEM mosaic of +5000 TIF files. All Z-values should be exaggerated by factor 10 as it's common in road construction.
...
2
votes
1answer
36 views
Methods for burning depressions (not rivers) in a DEM
I am using a 2x2m DEM to simulate runoff on a 2D hydrodynamic model. After a baseline simulation, I am interested in evaluating the impact of adding depressions in specific areas that may work as ...
2
votes
1answer
54 views
Creating a DEM from irregularly spaced contour lines in QGIS
I'm using QGIS to work with a contour line shapefile with contour lines that are not spaced evenly (e.g. not just 100 meter elevation increase between each line). The increase ranges from a 100 meter ...
0
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0answers
36 views
Clipping raster mosaic changes range of cell values to -3.4E+38 — +3.4E+38
I'm trying to clip a DSM mosaic I've made with a shapefile on ArcMap 10.7 but when I use extract by mask tool, the output is just empty and when I change the no data colour to red, all I get is a red ...
0
votes
1answer
20 views
Measuring distance between two points using digital elevation model (DEM) and ArcMap
I have a number of points mapped on a digital elevation model (DEM). The points were mapped on the DEM based on their GPS location (latitude, longitude).
What is the best way to measure the distance ...
1
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0answers
31 views
LiDAR DSM: difference between Return 1 and First of Many?
I'm making a DSM for an urban LiDAR dataset; I understand these typically are also referred to as "first return" rasters- I don't quite understand the difference though between Return 1 and ...
0
votes
1answer
42 views
Get DEM from Google Earth Engine
How can I get ASTER or SRTM DEM for years like 2016, 2020,... in Google Earth Engine? I can't filter date for SRTM DEM in GEE. It seems that SRTM DEM doesn't have multi-year data, it was captured only ...
-1
votes
3answers
67 views
Elevation profile of earth [closed]
Where can I find elevation data for the entire earth so that for a given location (coordinate) on the earth, I can find out the elevation of that particular location?
In particular, I am curious, what ...
2
votes
0answers
104 views
Extract morphologic characteristics of mountains from DTM in QGIS
I'm looking for some algorithm/script that allows the automatic extraction of peaks from DTMs into a point shapefile (including their morphologic characteristics such as key col, prominence, and ...
10
votes
1answer
203 views
Making an animation of an evolving digital elevation model
I'm working on a model of landscape evolution and would like to make a nice 3D movie of how the landscape over time. How do I do this?
My landscape evolution model, which is based on this paper and ...
0
votes
0answers
22 views
Converting a UTM .bil file to a lat/long TIFF
I have many 3 arcsec (90m) SRTM DEM files in BIL format in UTM projection that I need to convert into 1 arcsec (30m) lat/long TIFFs. I have tried both gdal_translate and gdalwarp to no success.
First ...
0
votes
1answer
51 views
Why am I getting this error when creating a DEM?
I'm using QGIS and trying to create a DEM using this tutorial:
https://www.youtube.com/watch?v=aJm9lewzooU
I'm getting error messages when trying to run "natural neighbor" with my file of ...
0
votes
0answers
18 views
Using QGIS to extract elevations of specific points from a DEM layer
With QGIS My objective is to extract Elevation Values from a DEM dataset. The locations to extract elevations come from a segp1 file. My DEM values are georeferenced to a UTM, my segp1 is ...
0
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0answers
40 views
How can I vectorize contour lines from a DTM in QGIS?
I'm using QGIS 3.16. I am trying to do the following: Starting with a DTM model (geoTIFF format) I am computing the contour lines (100m) with QGIS. So far, so good. In order to import the results into ...
0
votes
1answer
61 views
Calculate slope/gradient along streams (lines) segments in R
I would like to calculate the slope for stream segments in R. The stream network has been derived from the DEM. I have split the stream segments into equal parts of 100m (or less) and I have the DEM (...
5
votes
0answers
37 views
Finding geodesically flat regions in DEM data
I'm interested to find regions in some DEM data for Earth that are what I call geodesically flat, i.e. flat in the way that the path light travels is flat in the absence of strong gravitational fields....
4
votes
1answer
50 views
Remove DEM data in a specific region
I am trying to extract current USGS DEM data that corresponds to an old USGS map. I have downloaded the DEM covering the corresponding area, and am now trying to extract the correct subset. The area ...
3
votes
1answer
57 views
Generating vector slope maps using GDAL
I have a DEM file that I created a slope map of using gdaldem slope. This works fine and if I view and colorize it, I can now see how steep a hill is but now I'd love to create a shapefile out of that....
2
votes
1answer
38 views
Exporting separately ground and the sea from QGIS as TIFF files
I am very bad at QGIS, but I really need to have TIFF of the area on the picture, to export it later to Unreal Engine. The problem is the sea. Unreal takes it as a part of the ground. It doesn't ...
2
votes
0answers
37 views
Combining DEM, GeoTiff and CityGML in QGIS
I'm trying to combine DEM, GeoTiff, and CityGML in QGIS to create a 3D representation like in this example.
The problem I have is that:-
The CityGML buildings are hovering above the 3D view and
The ...
0
votes
0answers
24 views
Loading DEM .asc file in ArcMap
Loading a DEM dataset with .asc extension in Arcmap 10.7 (here the dataset http://www.sardegnageoportale.it/webgis2/sardegnamappe/?map=download_raster - select "DTM passo 10"; here the file ...
1
vote
0answers
70 views
Keep the map straight with arcgis projections
I need to overlap DEM file with an historical map.
The historical map doesn't have georeferencing so I need to add some control points, but when I do this the map is distorted.
There is a way to ...
0
votes
0answers
36 views
How to determine the visibility of a target at a fixed height above an observer on a given DEM?
I have a DEM, an observer position and an observer height above ground. Further I have a fixed height above the observer at which a flying target is expected. I now want to determine given the DEM, ...
1
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0answers
46 views
Georeferencing Moon photos and LRO DEM but how to model the curvature of the Moon?
I tried to search for solution to this, but I could not find it. However, if this matter has been dealt somewhere here, please forward me to a correct thread.
To summarize:
I am using QGIS and ...
2
votes
0answers
27 views
Linear Referencing and Z measurements
I am trying to build a linear reference route that uses the DEM derived distance instead of the default 2D distance. I have tried this How To (https://support.esri.com/en/technical-article/000008984) ...
1
vote
1answer
29 views
Conducting operation to shift DEM tilted on Z axis using PyQGIS
I have two DEMs of a stream channel created with photogrammetry from different times. One of the DEMs used ground control points and is georeferenced correctly. The other model did not use ground ...
1
vote
0answers
56 views
Artefacts when merging different resolution DEM
I am trying to merge a 10m DEM with a 30m DEM (10m DEM is a sub area of the 30m DEM). Both DEMs have the same projection and nodata value. I create a .vrt file:
gdalbuildvrt test.vrt *.tif -resolution ...
2
votes
1answer
35 views
Layer styling - raster symbology
I have two lists of raster (digital elevation model - DEM) layers by name. The first list of layers should be symbolized as follows:
symbology should be set to hillshade
layer rendering, blend mode ...
1
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0answers
53 views
What does this raster merging error code mean?
I was wondering if anyone could help me understand how to solve what this error message means and what I need to change to merge my DTM rasters with an asc extension. I am able to see the individual ...
1
vote
0answers
23 views
What Explained Variance is good to proceed with Predictive Soil Mapping?
I have 1851 soil samples data on pH covering a study area of 7482sq.km in northern Ghana and I am using 52 environmental long-term average variables (Relief, Climate, MODIS Reflectances and derived ...
3
votes
1answer
49 views
Getting unexpected DEM spatial resolution using ArcMap
I have downloaded SRTM DEM 30 m. However, when I displayed on ArcMap, I got a DEM raster with 0.0002777 cell size.
How can I solve this problem?
1
vote
0answers
47 views
Extracting Factors Causally Related to Landslides from DEMs (SRTM) [closed]
I have the SRTM dataset, and I've managed to write some python code to show elevation and slope heatmaps. The code runs fine, and the elevation data is reliable (I checked some points from the web), ...
5
votes
1answer
55 views
Merge Contour Boundary for Polygons QGIS
Hoping this is fairly simple but haven't been able to find much online. I am trying to create some elevation polygons from a DEM model.
Right now I am getting this after getting the contours, ...
0
votes
0answers
9 views
Geotiff files - Zoom into a specific zipcode/latlong/apn
I am new to Geo tools.
I am trying to assess the DSM/DEM of buildings in specific cities. So far, I could obtain a geotiff file from https://earthexplorer.usgs.gov/ and plot maps of the entire earth ...
