Questions tagged [dem]

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

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59 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 ...
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73 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 ...
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46 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, ...
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106 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 ...
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30 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) ...
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1answer
40 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 ...
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72 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 ...
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1answer
77 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 ...
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75 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 ...
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25 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 ...
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1answer
51 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?
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57 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), ...
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1answer
93 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, ...
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16 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 ...
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1answer
88 views

DSM void filling results into problems with pixels (using ArcMap)

Before writing here I exhausted any online resources, blogs, videos etc I could find. Here's my problem, with photos and a thorough explanation. I have a very high res DSM (5m) that has holes (voids). ...
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26 views

Performing ellipsoid to spheroid conversion using ArcMap

I have a DTM that is referenced to an ellipsoid (equatorial radius is not equal to the polar radius) and I want to convert the elevation values to the spheroid (equatorial radius = polar radius). How ...
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1answer
69 views

What algorithms can be used to create a DTM from a DSM TIFF file i.e that will reduce or exclude features such as trees and buildings

I am using Python and QGIS. I have obtained - purchased - a 1m DSM photogrammetry data file - a TIFF. I could purchase a DTM from the same company, but they are 5m grid, and so they lose some data I ...
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1answer
48 views

Mapping Tobler's hiking function with additional impediments using ArcGIS Desktop

Is there a way I can use Path Distance in ArcMap to calculate Tobler's Hiking Function with a DEM but also with additional time costs from non-slope impediments? For example, part of the landscape I ...
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13 views

What is wrong with DTM tiles in ArcMap?

I have downloaded Scotland 50cm (phase 3) DTMs for a location I am studying using Digimap. I don't know what has happened to the tiles. When I added them from ArcCatalog I had to select create ...
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18 views

Having trouble viewing DEM in 3D view

I am trying to view my DEM of terrain for a project in the 3D viewfinder, but having some difficulty. I can see it as flat terrain, but when I turn on DEM for the interpolation it disappears in the ...
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2answers
45 views

Padding DEM raster using ArcGIS Pro

I am wondering how I would go about padding the outside of a DEM raster with 0 values. Here's the scenario: I have a DEM and I have a feature class larger than the DEM footprint. I need the DEM to be ...
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304 views

Converting .obj 3D files to .tiff raster (or reading .obj on QGIS)

I received a 3d terrain model captured with a drone in .obj format. I am trying to open it in QGIS to use the elevation information as a georeferenced raster, but so far I can't open it or transform ...
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50 views

Assigning z values to polygon feature vertices in ArcMap

I am trying to assign z values to vertices of rectangular polygon features in ArcGIS 10.5 by using a DEM raster. I do not want to assign min, max, or mean z values to the polygons themselves, but I am ...
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35 views

Raster data from copernicus.eu

I have downloaded the raster data for Europe from https://land.copernicus.eu/imagery-in-situ/eu-dem (EU-DEM v1.1). To these data I apply the following orders: gdalwarp -s_srs EPSG: 3035 -t_srs EPSG: ...
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1answer
41 views

Iteration Error in Google Earth Engine?

The below code computes area elevation relationship by iteration algorithm. But when the interval sets to 0.5 shows same area values in a row(like the below picture). code link: https://code....
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31 views

How to calculate the slope of my polygons using DEM

I downloaded elevation data (DEM) of my study area from NASA and I converted it to slope. How do I calculate the slope of each farm at my study area? I have a shapefile containing the polygons of the ...
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1answer
141 views

QGIS: Creating contours at a certain elevation from DEM that match a value from a polygon layer

Trying to create contours from a 1m DEM at certain levels only when the contours fall inside a polygon with an field containing the desired contour elevation value. See images below. For example in ...
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1answer
191 views

How to convert CityGML (LoD2) to Digital Surface Model?

I'm very new to GIS and doing this for a university project. For evaluating Solar Potentials on Building Roofs I want to use QGIS 3 (the UMEP Plugin, with SEBE tool). Amongst other data I need a ...
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67 views

Defra LiDAR - Convert DTM to PointCloud?

Defra has DSM and DTM data for Blackwell in Birmingham, but no Point Cloud data. I am trying to get LiDAR Point Cloud data to build a golf course model (in TGC2019) for Blackwell, and this uses ...
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1answer
256 views

Vegetation removal from DEM before or after contour line extraction

I have a DEM from a terrassed olive grove (single trees apart from each other) and would like to get clean contour lines (without trees / bushes) from it using QGIS3. Cleaning up all the contour lines ...
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1answer
41 views

NASADEM total dataset size

I've recently started investigating NASADEM for some terrain visualisation tasks, and noticed that the total number of tiles on the Earthdata portal is way fewer than the global ASTER GDEM v003 ...
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73 views

What tools in QGIS can be used for calculating habitat structural diversity? [closed]

I have a canopy height model derived from a LiDAR DTM and DSM and I would like to calculate or illustrate habitat structural diversity from the canopy height model file. I have tried using roughness ...
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1answer
111 views

How to normalize a large point cloud using lasheight and a .tif DTM?

I am normalizing a large point cloud (>16 GB), for which I'm using a preprocessed DTM that I store as .tif. For smaller amounts of data, I would use an R script that lets me do this: library(lidR) ...
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1answer
185 views

Serving 1 band GeoTIFF float32 file in Titiler/riotiler

I am very new to GIS and setting up COG servers. The problem I am facing: I am unable to serve my DEMs/DSMs, which are in GeoTIFF format, as .png map tiles (z/x/y.png) using a tiling server "...
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82 views

GDAL cubic oversampling problem

I am trying to oversample a part of a big GeoTIFF DEM to display it as a hillshade. I'm doing the process in 3 steps: extract a part of my GeoTIFF oversample that part generate the hillshade with ...
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1answer
47 views

Using Topo to Raster tool

I am trying to make a DEM using topo to raster tool. When it is done a message pops up that some drawings Cannot acquire a lock, and the DEM is not visible. I have made a DEM before with the same data ...
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42 views

Creating fractional area coverages spatially for ArcMap

Some background first, I am working on a model that works with elevation bands. Elevation bands in sense that user defines the number of elevation bands in the area (just like reclassification of DEM ...
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59 views

Imitation of OpenTopoMap with DEM-data

I'm trying to imitate the OpenTopoMap with freely available DEM-Data. Which parameters do I have to change in my hillshaded DEM to get a similar look?
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1answer
127 views

Blending DEM hillshade with QMS basemaps

I would to keep the features of the ESRI Gray (Light) basemap crisp and clear on top of a hillshaded DEM in QGIS. So far, my attempts have not been very successful. The ESRI Gray basemap shows main ...
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140 views

Labelling point elevations of raster (DEM) using QGIS

I'm trying to create a map with spot levels using an underlying 1m resolution DEM TIFF file. My thought process so far is to create a grid of points with a height value field over the area of interest ...
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52 views

Raster Calculator for DEM Resolution

I am trying to perform a raster calculation of a DEM and I would like it to have any desired resolution of my choice. How can I write the code so that I adjust the pixel height and width in feet using ...
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1answer
43 views

Querying (DEFRA) height data from WSM, what's wrong with my GetFeatureInfo parameters?

I'm trying to retrieve DSM/DTM data from UK DEFRA WMS services in order to render in 3D. My background is in programming rather than GIS, although I've been dabbling a bit for a little while. I have ...
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0answers
40 views

Getting characteristic high points from DEM

I use QGIS 3.14 and I have a DEM file which I'd like to use to get a point layer with most characteristic high points from that DEM. So every top of the mountain, hill, hillock, low etc should be ...
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1answer
100 views

Seeking open source alternative to Spatial Analyst / 3D Analyst toolbox of ArcGIS Desktop

Is there a decent open source software alternative for the Spatial Analyst / 3D Analyst toolboxes of the ArcGIS environment? The main goal would be to demonstrate DEM interpolation and/or ...
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1answer
179 views

Calculating Slope from DEM in QGIS

I have a world DEM raster in QGIS in EPSG:4326 with elevation units in meters. I'm trying to get a raster of the slope of the terrain, and I'm doing so using the "Slope" tool under "...
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1answer
136 views

DEM for Russia in WGS84 [closed]

I'm looking for a DEM of Russia projected in WGS84. Anyone have any ideas on where to look?
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99 views

Using Aspect tool in QGIS

For my bachelor thesis in biology I´m working with QGIS 3.14 (Pi) and tried to create a layer where the slope aspect/expositon/exposure is presented. I´ve got a DTM1 on hands. There is this function ...
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2answers
74 views

Identify the coordinates of the max values resulting from using the Zonal Statistics tool

I used the Zonal Statistics tool to extract the max values of a raster/DEM layer. The attribute table shows the result, but the problem now is to identify the coordinates of the said maximum elevation....
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33 views

Meaning of statement in GRASS r.horizon manual

I have a question about this statement in the r.horizon manual: "If your projection is based on distance (easting and northing), these too must be in meters. The buffer parameters must be in the ...
2
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1answer
79 views

Get altitude value from WMS

If I load a WMS service into QGIS I could query with the selection tool for every pixel the altitude value. Where does QGIS get this altitude value from? A WMS does not normally have any altitude ...

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