Questions tagged [dem]
For questions about Digital Elevation Models (DEM), Digital Terrain Models (DTM) and Digital Surface Models (DSM)
1,932
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Make raster from min values of parcels
I have a DEM map and I've made some polygons. I split those polys into parcels(grid).
I want to take the min value (height) of each parcel and make new raster with that value fill'ed in. Then I would ...
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23
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QGIS - WMS Service DEM (re)calculate height
Is there a way to calculate the height, or recalculate the raster image, that was screenshoted from a WMS Service (DEM - digital elevation model) - f.e. the pixel-value is 118 but the height in that ...
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12
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Creating a heightmap from hillshade/radar data?
So there are several threads explaining how to create a hillshade map from DEM. Does anyone know of a method to do the opposite? Essentially all I have is unidirectional radar data which functions ...
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27
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DEM derived from LiDAR in wrong location
I am trying to derive slope and aspect from a DEM that was derived over a mine using LiDAR in ArcMap v 10.8.1 . However, the DEM seems to be in the wrong location (further North from the Area of ...
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11
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Cartosat DEM differencing giving absurd readings
I have performed these steps for carrying out DEM Difference of two images:
I had 2 pair of Cartosat Stereo Imagery. I used NASA AMES Stereo Pipeline to generate two
Point Cloud then used points2dem ...
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16
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Stepping artifacts - Merging raster data in ArcGIS Pro
I am working with a large number of raster datasets within multiple geodatabases in ArcGIS Pro. The original source data are imported from ASC format converted from UTM29N to WGS84 (Bilinear ...
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33
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Removing Tree Cover from DSM Before Creating Contours?
I am very new to QGIS and seem to be stuck.
I cannot figure out how to remove trees from my DSM (generated in Pix4D Cloud) in order to generate contours.
I have tried following various turorials; ...
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2
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194
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Extract raster value at each vertex from line, while keeping the line
So I have a line that is basically drawn from two points. A starting point and an end point. It looks like this:
I then densify the line by count and set the value to e.g. 50
Then I explode the line ...
- 911
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1
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33
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Removing georeferencing from DEM using ArcGIS Pro
I am creating an assignment for students to demonstrate different visualizations of LiDAR-derived DEMs. However, because the DEM is currently unpublished and contains archaeological features, I want ...
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33
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How to burn a sewer network into a DEM
As part of the sewershed delineation using the ArcHydro toolbox in ArcGIS Pro, I need to burn my sewer network into the DEM to recondition it based on pipe elevations. I have calculated and added the ...
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43
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QGIS - Aligning Cells from Multiple Overlay DEM's [closed]
I am modelling a volcano with a changing landform using 5 overlaying DEMs at different stages of the volcano collapse. I need the cells of each DEMs to line up vertically so I can obtain elevation ...
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29
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Creating non-smoothed / Stepped DEM from contours (ArcMap or ArcGIS Pro)
I am attempting to create an artificial DEM that is stepped / not smoothed (imagine the profile below). I have created contours for levels A & B
Topo to Raster produces a smoothed profile (see ...
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1
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58
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Negative elevation results from USGS 1 meter DEM [closed]
The USGS 1 meter Digital Elevation Model will return negative elevations. The elevations are based off NAVD88. The negative elevations appear to be near/over water along coastal areas. This DEM is ...
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46
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Flow direction outputs (ArcGIS Pro: Hydrology Tools) returning 255 values rather than 8 (D8 settings)
I am working with 10-meter resolution digital elevation models to produce flow direction raster images to be used ultimately for the watershed tool in ArcGIS Pro. When I use one DEM at a time, things ...
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29
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How do I fix the average shading of many .hgt tiles in QGIS?
I downloaded many .hgt files to map California. When I open them in QGIS, the borders line up perfectly, but the average height shading is different for each .hgt file. Is there a way to average out ...
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26
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Raster and vector analysis for profile extraction in Python [closed]
I have quite complex problem and I have two options to solve it. For a multiline shapefile (river) I would like to get cross profiles and extract DEM values for the lines.
I was thinking 1: Create ...
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Validating that the smallest channel extracted using ArcMap (Hydrology toolbox) from DEM is the first-order stream
In ArcMap, the 'Hydrology' tool under the toolbox 'Spatial Analyst' can be used to extract the stream network, as described in detail here: extract streams from DEM. One step consists of using a ...
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44
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Lower or smoothen elevation data/DEM [closed]
I have a linear.shp that represent a road about 20m in width. It is going across tall mountains and steep hills (don't worry about the logic on how a road is going over a mountain).
I need to (change, ...
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30
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Raster DEM projection rendering problem
I am new to QGIS and am using it primarily for the DEMto3D plugin. My use case is creating STL meshes so I can CNC carve scale models of the landscape features as art pieces.
I purchased one meter ...
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75
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Vertical transformation of DEM from EPSG:3035 to EPSG:4326
I am trying to convert a DEM file from EPSG:3035 (ETRS89-extended / LAEA Europe) to EPSG:4326 (WGS 84) with gdalwarp. EPSG:3035 uses the European Terrestrial Reference System 1989 ensemble datum where ...
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32
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Detect sharp changes in elevation
I've been scouring the forums to see if there is a way to detect sharp, unnatural elevation changes greater than a certain amount in ArcGIS Pro. I've run across an issue in some DEMs where there are ...
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31
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Importing DEM into Microstation
Using QGIS version 3.28.2-Firenze. I have a DEM obtained from USGS (EPSG:2927 - NAD83(HARN) / Washington South (ftUS)) which aligns correctly horizontally and vertically when I overlay on top of OSM ...
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2
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65
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Polygons from a raster within an elevation range
In the image below I have generated some isolines starting from the terrain model and I have filtered them within a certain elevation range 800 - 1500m of elevation in QGIS.
But I would like to make ...
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14
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Quickly generate multiple hillshades from DEMs in ArcGIS Pro
In ArcGIS Desktop I would usually use ImageAnalyst app where it was easy to quickly generate hillshade from DEMs that are in data frame. But I can't find anything similar in ArcGIS Pro version, except ...
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43
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How to convert 2D surface area into 3D surface area using DEM
I have a polygon layer of the area burned by wildfire, which lies in the very hilly terrain. The polygon of the burned area was drawn manually over the ortophoto, which means, that the polygon has ...
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38
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Adjusting heights of two DTM rasters using ArcMap
I have two DTM rasters of a forest area. The base heights of the winter DTM must match the base heights of the summer DTM.
How can I adjust them using ArcMap?
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47
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How do I find the correct projection of a DEM to be used for viewshed analysis?
My data download from Earthdata.nasa.gov for a DEM is in WGS84 CRS. I am aiming to create Viewshed using QGIS 3.14 but I am getting the below error message:
Raster pixels are irregular in shape (...
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1
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39
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Determining slope percentage using ArcMap
I am working on a project where I need to conduct a MCA. One of the criteria is: if the slopes are greater than 15%, they should not be used at all. I have DEM model and a slope has been made in ...
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302
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Elevation from TIFF file
I am new to QGIS. I have an Excel file with latitude & longitude points and a GeoTIFF (.tif) file. Now I want to get the elevation of all latitude & longitude points in the Excel file. How to ...
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113
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Burn polygons into DEM raster layer in QGIS
I am trying to take a Digital Elevation Model raster layer and “burn” polygons into it, so that they show up in the DEM layer. I know there are methods for burning streams/rivers into raster DEMs, but ...
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37
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Identifying (spotting) holes (pits, depressions) on surface using DTM and highlight them
Is there any way to identify all the ”holes” on a surface (DEM, DTM) - (pits, depressions) and highlight them using ArcGIS Pro?
I need for example to highlight all the ”holes” that are more deep than ...
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35
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Convert smoothened contour in QGIS ( vector) to raster for use in HECRAS
I have generated contours in QGIS using point data (AutoCAD file) and I had to also smoothen the contours and remove noises (smaller contours) from the contour generated. I need to get this contour ...
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24
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ArcGIS Pro: Vertical datum Transformation with custom parameters
I have a DEM/tif which has local austrian height values in the raster cells in the MGI datum. (EPSG for the height values: https://epsg.io/5778)
I need to make an inverse 7-parameter vertical datum ...
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2
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72
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Importing DEM ArcGIS REST Servers and Hillshade using QGIS
I'm brand new to GIS and just discovered QGIS.
I've been trying to import either DEMs or LIDAR of my area from the following link:
https://basemap.nationalmap.gov/arcgis/rest/services/...
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Convert a raster to show count of cells of a given relationship to each cell
Is there a tool (QGIS preferably), that will look at every raster cell, and compare it to neighbouring (1km) cells and populate the value with a value based on relationship.
Example (and indeed the ...
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60
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Measuring real distance in QGIS
I created the linear shapefile of an ancient Roman Road (via Flaminia), and I would like to compare the linear total distance with the real one: Roman engineers and Gromatici measured the roads with a ...
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3
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130
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DEM 3D problem in QGIS
I am facing a problem to make this DEM 3D problem in qgis2threejs plugin scene. Does anyone have solution on it?
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Feed pixel type of tiles into MosaicToNewRaster()
I am automating the creation a mosaic raster dataset from thousands of individual elevation tiles and am tying to extract the pixel type metadata from the input tiles and specify this pixel type in ...
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49
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SAR and elevation models
Is an existing Digital Elevation Model (DEM) necessary to process Synthetic Aperture Radar (SAR) imagery?
From earthdata it seems a DEM is necessary. It uses the 30-meter: GLO-30 Copernicus DEM to ...
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Elevation dataset appears to have come with all of the Eastings wrong
I'm working with QGIS 3.12, trying to create a basemap of a mine site in Alberta for an env sci related project. I downloaded the 20k ASCII DEM from Altalis and imported the .gnp layer; which is a ...
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55
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Problem Facing while performing Interferometry using Sentinel-1 image
I am using sentinel 1 data to extract the surface elevation using snaphu-unwrap tool. I perform all the steps according to literature and all the steps provide data too. However in the last step where ...
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Finding height profile of region from DEM
I'm trying to work out how to obtain a height profile of a region (a county) from a 50m DEM. I have seen height / elevation profiles for regions created before but don't know how to do it and have had ...
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Does the 0m elevation height of a Digital Elevation Model (Copernicus DEM) correspond to mean sea level?
I want to model future coastal flooding caused by sea-level rise under the latest IPCC scenarios at global scale. To this end, I use the Copernicus Digital Elevation Model (Copernicus DEM: https://...
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Ortho-rectifying standard non-rectified Maxar satellite imagery
For a project we received 50cm brushed up LV2A OR2A BGRN-spectre satellite imagery from Maxar. No GCP are mentioned in the metadata and at the intersection of overlapping map tiles the angle of the ...
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80
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Exporting elevation data within rectangle from DEM in Google Earth Engine
I have a situation where I want to export elevation data from a DEM.
I am using the RGE ALTI: IGN RGE ALTI Digital Elevation 1m DEM.
Currently I have extracted the MNT band, containing the height for ...
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36
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Reprojecting DEM of Sinai, Egypt-Israel to use in viewshed analysis
I am trying to create a viewpoint on a DEM map of the Sinai with QGIS.
The original DEM downloaded from earthdata.nasa.gov came as CRS WGS84. I cannot use this to make a viewpoint for my viewshed ...
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53
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Fixing errors in old DTM in QGIS
I'm currently working on fixing some errors in some old DTMs.
The issue is there are pixels with a value of "-1.4013e-45" which are all over the rasters. I'm looking for a way to remove ...
4
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1
answer
134
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Sampling points in raster without generating new file in QGIS
I am aware that there are tools available in QGIS for sampling a raster at any given point from a shapefile.
The methods I've tried are:
Point sampling tool plugin
Raster analysis > sample raster ...
- 299
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41
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Setting negative DEM values for the sea and water bodies to zero
I've downloaded a few of the Cartosat-1 CartoDEM Version-3 R1 files from BHUVAN (https://bhuvan-app3.nrsc.gov.in/data/download/index.php).
The files seem to be in the WGS84 format and have values of -...
- 43
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115
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Creating DTM from COPC LAZ Files using PDAL
I have been running into issues with PDAL and a Batch script I am running.
I have a series of Cloud Optimized Point Clouds (COPC) and I am looking to generate a DTM from them.
I am using the following ...