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Questions tagged [dem]

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

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Why is there a difference between Raw and Rendered results?

I saved two images from a Dem Tiff file in two different formats. There is no problem when saved as raw format. However, when you save it in rendered format, something like the second picture appears. ...
William24's user avatar
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1 answer
65 views

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 ...
Routhwick's user avatar
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9 views

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 ...
Synchrondyne's user avatar
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1 answer
54 views

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 ...
tomtomnz's user avatar
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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 ...
William24's user avatar
1 vote
0 answers
40 views

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. ...
Jama's user avatar
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0 answers
21 views

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 ...
Francesco Callari's user avatar
-1 votes
1 answer
50 views

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 ...
William24's user avatar
1 vote
1 answer
441 views

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 ...
William24's user avatar
0 votes
1 answer
57 views

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?
Mohammad Elyas Hamidi's user avatar
1 vote
1 answer
95 views

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 ...
Dimitris K's user avatar
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50 views

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 ...
Alexander Kutschera's user avatar
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1 answer
40 views

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 ...
CuriousLurker321's user avatar
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0 answers
53 views

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 ...
Mathias's user avatar
1 vote
1 answer
51 views

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 ...
user240982's user avatar
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1 answer
42 views

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 ...
Fabi's user avatar
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4 votes
1 answer
486 views

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?
GISGirl94's user avatar
-1 votes
1 answer
34 views

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 ...
aogino's user avatar
  • 15
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0 answers
33 views

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 ...
ruthenia_rouge's user avatar
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0 answers
45 views

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 ...
ckatz19's user avatar
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0 answers
20 views

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 ...
aogino's user avatar
  • 15
1 vote
0 answers
40 views

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?
Fabi's user avatar
  • 85
1 vote
0 answers
33 views

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 ...
Wolfgang Haak's user avatar
0 votes
2 answers
67 views

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 ...
aogino's user avatar
  • 15
0 votes
0 answers
14 views

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.
kc_nul's user avatar
  • 111
0 votes
1 answer
31 views

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 ...
Fitch's user avatar
  • 49
1 vote
0 answers
37 views

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 ...
andreaordonselli's user avatar
0 votes
1 answer
45 views

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 ...
VSA's user avatar
  • 11
0 votes
0 answers
21 views

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 ...
vdc's user avatar
  • 309
1 vote
1 answer
45 views

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. ...
Someone's user avatar
  • 25
1 vote
0 answers
72 views

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 ...
Amine MB's user avatar
0 votes
1 answer
36 views

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 ...
BAE_23's user avatar
  • 677
-1 votes
1 answer
37 views

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,...
aogino's user avatar
  • 15
0 votes
1 answer
44 views

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 ...
Manuel Azancot's user avatar
0 votes
1 answer
28 views

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 ...
jlSta's user avatar
  • 1,096
2 votes
1 answer
140 views

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 ...
swiss_knight's user avatar
  • 10.5k
2 votes
0 answers
26 views

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 ...
Mike's user avatar
  • 21
1 vote
0 answers
21 views

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 ...
GIStree's user avatar
  • 91
1 vote
2 answers
91 views

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, ...
Hanna's user avatar
  • 11
0 votes
0 answers
61 views

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 ...
Ben's user avatar
  • 1
1 vote
1 answer
46 views

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 ...
stewaoi's user avatar
  • 11
0 votes
1 answer
73 views

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?...
Cynthia Fowler's user avatar
0 votes
1 answer
44 views

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 ...
Patschenkof's user avatar
1 vote
1 answer
35 views

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 - ...
Seth Lutske's user avatar
0 votes
0 answers
38 views

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 ...
oliver's user avatar
  • 95
0 votes
0 answers
48 views

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 ...
Yuxuan Ye's user avatar
0 votes
1 answer
49 views

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 ...
Deskrub's user avatar
  • 23
0 votes
1 answer
159 views

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 ...
elevation_modeller's user avatar
1 vote
1 answer
73 views

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 ...
Gilles's user avatar
  • 405
0 votes
0 answers
33 views

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 ...
waiiana's user avatar
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