Questions tagged [dem]
For questions about Digital Elevation Models (DEM), Digital Terrain Models (DTM) and Digital Surface Models (DSM)
2,049
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QGIS point sampling misses data on edge of raster (possible bug?)
It seems I may have discovered a shortcoming in the way QGIS handles raster sampling in points. Since yesterday evening (18/7), one small issue has begun to elude me (during my comeback geofictional ...
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9
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Reprojecting to rotated orthographic projection in rasterio
I have some DEMs in a lunar polar stereographic projection (from LOLA). I would like to reproject them to a orthographic projection with a custom azimuth rotation using rasterio. I can pretty easily ...
- 101
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52
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QGIS fill individual sink
I’m trying to determine the maximum extent of a pond when it is filled to its maximum capacity.
I think this is the same logic as the sink filling algorithms used for hydraulically correct dem’s - but ...
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40
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Brightness Differences in DEM TIFF File
I created a DEM file with QGIS. File type TIFF. The files I use as sources are also TIFF. The file, which looks normal in QGIS, looks different when I look at it in other programs. When I open the DEM ...
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40
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Why does my raster look different after clipping it by a mask layer using QGIS?
I have a Digital Elevation Model of Europe and I want to clip it to the extent of Germany. To do so, I am using Clip Raster by Mask Layer with the external frontier of Germany as the mask layer. ...
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19
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WGS84 elevation from ALOS 30m DSM tif's using rasterio
I am new to GIS processing.
I am trying to compute WGS84 elevation for given latitude and longitude using the JAXA ALOS 30m DSM. I use rasterio and code from a minimal example I found that looks like ...
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1
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48
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I can't fill in the gaps in the DEM map [closed]
I downloaded the DEM files of the Balkan peninsula from the USGS website. I created a Balkan Peninsula DEM map larger than 3 GB from more than 130 DEM files, each of which is 25 MB. However, there is ...
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435
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130 TIF DEM file (total size 3 GB) become 7.4 GB TIF file after merging. Why?
I combined (Merge) 130 DEM maps via QGIS, taking up 3 GB in total. However, the total size of the combined file was 7.4 GB. I'm new to QGIS. It's only been a few weeks. I don't understand why the file ...
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57
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Merging DEM with different resolutions
I am going to merge two DEM raster files with different resolutions (5m and 12.5m). I would like to merge them in a way that they should keep their own resolution.
How can I do this in ArcGIS Pro?
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94
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DEM < 10 Meters - Greece
I would like to know if there is any free or to buy option (site) from which I can buy/download a high resolution DEM for a small region in Greece. Except from USGS and OpenToography where the ...
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50
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Combine DTM with hillshade in QGIS
I'm wondering if it is possible to combine a LiDAR generated DTM on a 1m Scale with a Hillshade DTM on a 0,25m Scale to improve the level of detail of the LiDAR DTM.
If possible how can this be done ...
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39
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GSD or pixel size for volume
When I want to calculate the volume of a building polygon (in my case), do I use the GSD that I received in a WebODM report or the pixel size of the elevation raster? What is the difference between ...
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53
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Issue generating DEM with Natural Neighbour in QGIS 3.6 on different computers
I am trying to create a DEM using the Natural Neighbour algorithm in QGIS 3.6 Noosa. On my personal computer, I can successfully generate the DEM despite encountering a warning (shown in the attached ...
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51
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QGIS DEM to elevation Points, pixels not centred
I have a DEM which I'm trying to convert into a point layer in QGIS. I used the raster pixels to points tool, which seemed to work, except that the points are not in the centre of the DEM pixels. They ...
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40
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QGIS: Set two raster to the same height
I have 2 DEM raster in QGIS. I want to merge them, but they have a difference in height of approx. 9m. This means that when I merge them, there is a kind of break-off edge at the transition. Can I ...
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485
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What does "post to post" mean?
For example, when someone talks about the "post to post" elevation error of a DTM, what exactly are they referring to?
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What type of web service do GMRT and OpenTopography offer?
From what I understand, GMRT and OpenTopography offer web services for DEMs in geotiff format (raster with unique band of 16 or 32bits) whereas OGC web services serve 3 band rasters.
What's the name ...
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33
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Find Python library to work with DEM in GeoTIFF format [duplicate]
I'm looking for a library for Python that will allow me to do the following thing:
I have a DEM in GeoTIFF format, and I have a list of points with coordinates in Lat/Lon format. I need these points ...
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45
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Calculating accurate viewsheds using DSM and DTM lidar data QGIS
I have a question regarding using DSM (Digital Surface Model) and DTM (Digital Terrain Model) data sets to create Zones of Theoretical Visibility.
I used the QGIS Visibility Analysis plugin to create ...
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20
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Choose DEM layer as terrain in 3D view using PyQGIS
I saw that many 3D classes and methods have been exposed to PyQGIS so I was wondering if choosing a raster layer as a terrain was now possible. I'm working on QGIS version 3.36.1.
This is the GUI ...
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39
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QGIS: Further subdivide sub-catchments based on DEM
I have a DEM and a vector layer with existing hydrological sub-catchments. Is there a way in QGIS to further subdivide the sub-catchments based on the DEM?
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How to augment LiDAR/DSM data from 3d models
For a viewshed analysis in QGIS 3.34, the I have LiDAR/DSM geotif files available. I want to modify/augment the DMS layer by adding the height information from 3d models of specific buildings. This ...
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66
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Importing DTM from WMS
I used a GetMap request to query a DTM layer (French national DTM coverage called RGE ALTI) in GeoTIFF format. However the resulting layer has 3 bands instead of one. My end goal is to visualize it in ...
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14
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Information in addition to Raster zonal statistics
I have a layer of polygons and a DSM. I want to know if I can extract average aspect, slope, and elevation statistics all at once in QGIS. I know another software does this but I forgot the name.
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31
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QGIS - transfer outcrop pixels from a DEM raster onto another raster surface at a lower level
In QGIS I would like a solution that will transfer pixels from a DEM raster onto another raster surface at a lower level. I am trying to create 2 geological surfaces, one being ground level (GL) and ...
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Starting from a DEM raster, is it possible to arrive at a polygonal layer with a slope greater than 30% not in squares?
On this site it is possible to download DEM maps of Italy with an accuracy of 10 meters: https://tinitaly.pi.ingv.it/Download_Area1_1.html
Bringing this raster into QGIS and running the Slope command ...
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45
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Raising/lowering extracted contour layer using QGIS
Is there a way to raise/lower an extracted contour layer?
I've scoured the properties panel and have tried to raise/lower "elevation" menu, but when I make changes there nothing happens to ...
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21
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DEM update/interpolation algorithm from control points
Context: I have a reference DEM, and Icesat-2 points covering some parts of it. The DEM is from 2012 and the Icesat-2 points range from 2018 to 2023.
Goal: I am looking for a way to 'update' the ...
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45
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Using CreateMosaicDataset_management and AddRastersToMosaicDataset_management in ArcPy
I have a standalone ArcGIS Enterprise Server 10.8.1. I am also using ArcPy with Python 2.7.18. I want to publish an Image Service to my server by creating a SD file, given a folder of DEM .tif files. ...
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69
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Make a slope-aspect map and create a circular legend for it in QGIS
I'm working on Terrain analysis of my ROI and could compute aspect and slope separately. Although I found a fairly easy tutorial on how to make a slope-aspect raster, I want to know if it's possible ...
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36
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Combine Slope and Aspect of a DEM for suitiable PV-Powerplants
I want to get areas for PV-Powerplants via QGIS.
I used the solution under Filter for south pointing areas from a DEM for extraction of the areas which are not facing north (60-300°).
But I need ...
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Python CLI/Package to handle DTM conversion from raster to mesh (obj or ply) [closed]
I was wondering if there is a Python CLI, package or even a QGIS tool that makes it possible to convert a DEM from raster to mesh. The only way I found at the moment is sampling points from the raster,...
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44
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Wrong elevation of DEM
I received a DEM made without calibrate the elevation with ground control points, the result is a DEM with 5 m below the real surface. How can I fix this issue if the plane coordinate are perfect, the ...
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28
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Load granule subset (tiles) from mosaic based on shapefile footprint (grid) with QGIS
I downloaded DTM RGE ALTI® from french IGN here
The directory contains a mosaic of granules :
I would like to load only a subset of the mosaic.
The dowloaded product contains a shapefile named ...
- 1,096
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136
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QGIS Drape (set Z value from raster) to set Z-value along all pixels under a geometry (not only vertices)
In QGIS (3.34 at the time of writing), the "Drape (set Z value from raster)" algorithm (native:setzfromraster) allows the user to assign a Z value to a given vector geometry using a raster ...
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Conversion of a DEM model from Baltic Height system 1977 to EGM96
I have a raster DEM model (geotiff) with horizontal coordinate system EPSG:4326 and vertical heights regarding the Baltic Heigts system 1977 https://epsg.io/5705
I'm trying to convert it into EGM96 ...
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Elevation discrepancy while clipping a DEM in QGIS 3.28.9
I clipped a DEM (Clipped mask) using the GDAL Processing Tool - clip raster by mask layer from a DEM (clipped).
The maximum elevation value of the Clipped mask is 7286m, while the same in the clipped ...
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Points-Elevation from DEM via WMS
I am trying calculate elevations of points (which I collected via GPS on phone) to save as a base line of study area. Here is what I did: First, input the points as geotagged images to QGIS. Second, ...
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61
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USGS 3DEP 1m issues with quality and Google Earth Engine
I have an issue when layering elevation data using hillshade with USGS 3DEP 1m DEM.
Some areas in the US I get artifact lines(lower quality?) on my hillshade layer, while other areas in the US I get ...
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46
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QGIS - Matching Exported Files to Print Layout Exports
I am exporting a u16 bit DEM of New Zealand's South Island using the save as > raw data method and specifying a lower resolution (to reduce the file size). This is after warping the data to my ...
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73
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How to replace bathymetry in a DEM
I have a merit DEM TIFF file and in that file, I simply wish to replace some values by taking values from another TIFF file that has bathymetry data for a lake.
Can I do this using a raster calculator?...
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43
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Conflicting date ranges for COPERNICUS/DEM/GLO30 in Earth Engine
I'm trying to filter DEMs from the COPERNICUS/DEM/GLO30 ImageCollection in Google Earth Engine by date. However, the date range I'm getting from the collection seems incorrect, leading to filtering ...
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35
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ArcGIS JS API RasterShaderReliefRenderer does not color full range of DEM elevation values
I have a DEM of the state of florida as an ImageService, here. I want to render this DEM using nicer colors than black and white using the ArcGIS JS API. Following the example ImageryTileLayer - ...
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38
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Colour intersecting viewsheds by number of intersects
I'm creating a PyQGIS plugin which utilises the Grass7 r.viewshed algorithm. It creates viewsheds as .tif Layers in the project, using the main raster layer as a Digital Terrain/Elevation Model for ...
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48
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Converting vertical datum of Lowest Astronomical Tide (LAT) to EGM96
I want to model the impact of sea level rise (SLR) on the coast zone of an Asian country using a modified bathtub model. The SLR projections include AR6 results and extreme sea level (ESL) by high ...
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49
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Outlier's neighbours of a raster analysis in Python/GIS
Starting with point clouds from various drone flights, I created a 0'1x0'1m cell raster with the DEM of Differences (DoD). Next, in order to clean outliers cells, I calculated the 0'1 and 99'9 ...
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159
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GRASS r.horizon returns nonsense
I am trying to calculate the horizon profile from a point on a mountainside, through the appropriate DTM elevation file and the GRASS function r.horizon.height (via QGIS).
However, the output looks ...
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73
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QGIS DEM (Raster) merge: errors
I'm trying to merge 4 tiles (ASC) of a French 1m digital elevation model.
Files are loaded in QGIS, they bear no errors, value range is coherent.
Merging comes with errors and the result is a raster ...
- 405
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32
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Generating orthomosaic from DEM in Metashape
I'm using Metashape to make a point cloud from georeferenced drone images using the basic workflow (Align photos -> Build Point Cloud). I then export that and align it to a LiDAR cloud we have from ...
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43
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Identifying / digitising small surface features automatically in QGIS
I need to locate small features on a digital surface model (dsm) in qgis and get their coordinates.
I have a field surface with distributed molehills they show up in the dsm but is there a tool that ...
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