Questions tagged [terrain]

The vertical and horizontal dimension of land surface

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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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Service area depending on slope in QGIS

I am trying to create isochrons of walking depending on slope in QGIS. I am using the Service Area function and I have a slope assigned for each road. But I don't know how to determine the direction ...
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42 views

Most detailed surface map that can be produced from LiDAR data in ArcMap

I want to find old military trenches or at least to get an idea where they were, so that I can go to those areas and survey them. I know the basic method of conversion from .lasd to elevation raster ...
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-1 votes
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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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Import a Map from gokml.net to QGIS

I want to import this map into QGIS: http://gokml.net/maps#ll=48.093157,12.355834&z=6&t=t&s=14 It's the only way I found to display the Google Terrain Map without streets and labels. If ...
2 votes
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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 ...
2 votes
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51 views

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://...
1 vote
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QGIS: Average of digital terrain model for a certain polygon

In one layer I have a lot of different polygons, which represent different areas. In addition I have downloaded a digital terrain model, which shows different slope percentages. All of this works, but ...
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Terrain Ruggedness index to polygon

I need to calculate ruggedness for a circular region extending x meters away from a central point. The TRI function in Terrain uses Wilson (2007) equation to calculate TRI for an entire raster TRI <...
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1 vote
1 answer
239 views

What is the difference between TIN vs MESH vs TERRAIN in the context of GIS?

I couldn't seem to fully understand the differences between TIN, MESH, and TERRAIN dataset formats in GIS. Per Wikipedia a triangulated irregular network (TIN)1 is a representation of a continuous ...
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How to determine the area size of a terrain for which I want to calculate its roughness

I want to calculate the wind speed on the ground for a specific location. In order to do so I will use the log wind profile. One of the input variables of this formula is the surface/terrain roughness....
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1 answer
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Terrain creation error using a GeoTIFF file with HEC-RAS 6.2 - "object reference not set to instance of object"

I am attempting to import a TIFF file created in QGIS, into HEC-RAS. I have a projection file as the SRS definition for HEC-RAS, which is derived from a shapefile that lines up with the spatial extent ...
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Band used for deformation estimation using In-SAR

Which polarization of SAR data (C-band - Sentinel-1A) shall I use to get a better deformation map of a mountain terrain - VV or HH?
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70 views

Calculate slope along line feature for line segments of equal elevation?

I would like to calculate the surface slope of a glacier in the Swiss alps. In ArcGIS Pro this can be done using the Add Surface Information Tool. The output is a data table with the slope for each ...
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Terrain correction TerraSAR-X images

I am trying to perform terrain correction on a SAR image using GDAL. I tried using simple gdalwarp, but the accuracy is not enough for me, so I decided to use: gdalwarp -multi -wo NUM_THREADS=ALL_CPUS ...
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1 vote
1 answer
181 views

Error calculating aspect from DEM in R using raster/terra

I have a DEM file gathered using R. The raster and terra packages both have a function to calculate aspect, called terrain(). When using the terrain() function and the units="degrees" ...
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2 answers
258 views

Converting aspect/direction raster from geographic degrees to arithmetic radians

I have a raster/grid representing e.g. terrain aspect or flow direction, coded in geographic degrees (0-360°, clockwise from the north). I would like to convert it in arithmetic radians (0-2π, ...
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1 vote
1 answer
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Creating TIFF from Contour Lines

I need to quickly create a TIFF terrain (shades of grey terrain) from contour lines, or rather to create a GeoTIFF. In the past, I extracted vertexes from the contour lines and used that to create new ...
2 votes
0 answers
203 views

Generate GLTF/OBJ models from quantized mesh (terrain) in CesiumJS?

I’m exploring ways to generate gltf / obj models from terrain mesh. My goal is to show 3d cut-fill volume calculation, something like the following - I realized that I don’t need to DEM to generate ...
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126 views

How to query height of a given lat long coordinate from server side?

I need to some calculation with terrain surface, I use cesium but it works slow. Cesium has a method sampleTerrainMostDetailed, it gives me height of given coordinates but it calculates height on ...
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2 answers
103 views

Creating Contour Lines in QGIS 3.16 with a distance of 0,10 m

I would like to create Isohypses (Shape) ("Create contour lines") with a distance of 0,10m in a Digital Terrain Model (Shape File). While processing the command, there are some errors poping ...
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181 views

Plan curvature in QGIS

I am trying to obtain plan curvature from a DEM. So far I have tried two methods from SAGA and GrassGIS plugins, however both do not seem to work and give errors. Do you have a workaround suggestion? ...
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2 votes
1 answer
557 views

Using Watershed Basin from SAGA in QGIS

I have a weird phenomenon going on in QGIS. I want to derive a channel network and also the catchment areas using "watershed basin" from SAGA. In the end I want to have the flow direction ...
0 votes
1 answer
155 views

How to interpret Terrain Ruggedness Index according to Wilson et al. (2007)?

Is there a categorical scale used to interpret values from the Terrain Ruggedness Index as calculated by Wilson et al. (2007), which is used in the raster library in R?
2 votes
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176 views

Interpreting Ruggedness Index calculated from SRTM Tiles

I am looking for help interpreting the values from Ruggedness Index calculations. I downloaded SRTM tiles using the SRTM Downloader plugin in QGIS. Then I calculated ruggedness from SRTM tiles in QGIS ...
2 votes
1 answer
392 views

Intersection of an arbitrarily oriented 3D plane with a terrain DEM

In a nutshell I'd like to compute the intersection of a 3D plane (defined by 3 points) and a terrain (given as a raster DEM GeoTIFF), and more particularly the part between two lines of that plane. ...
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Calculating direct solar radiation using QGIS and GRASS

I am using QGIS 3.16.8 and GRASS 7.8.5. I would like to compare two places in my study area climatically. Since both are only a few 100 metres away, I assume that they only differed in terms of slope ...
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1 answer
176 views

Reproducing terrain ruggedness index from the original paper example [closed]

I am not able to reproduce the terrain ruggedness index for the example used in the original Riley et. al paper. The example is as follows: When I try to reproduce the numbers in MS Excel I get ...
2 votes
1 answer
167 views

How to calculate the terrain profile in Profile Tools plugin

Now, I'm trying to calculate terrain slope(°) using pyqgis using below process. Along the specific lines which I want to know the terrain profile, I generated the points using 'qgis:pointsalonglines'....
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2 votes
1 answer
159 views

An error occurred when using the terrain function in the production of Shiny dashboard

I am new to the 'shiny' package. I just try to produce an aspect map from the existing DEM data using the Shiny dashboard for training purposes. However, I faced the below warning in R and error in ...
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91 views

Grid from SAGA natural neighbor results in black grid

I'm new in QGIS and I'm following tutorials mainly on YouTube so I created a path in Google Earth then exported to kml which is converted to txt via GPS visualizer. When added delimited layer it shows ...
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1 answer
387 views

Why do I get negative values for the topographic position index (TPI)?

I run into issues, when trying to calculate the topographic position index (TPI). I get values ranging from -13 to 17. And the resulting layer looks a bit odd, too: If I understand it correctly, this ...
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1 vote
1 answer
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Free or FOSS Elevation API for Heightmaps (image files) instead of elevation points

I'm coming from a Blender background, in which simple FOSS extensions exist (like BlenderGIS) that download SRTM/Aster Elevation Data and make a terrain based on this. I'd like to make something ...
0 votes
1 answer
88 views

How to get elevation raster data at custom scales for a specific region?

I'm new to GIS and trying to obtain elevation data for a specific region, transformed to raster data with a custom cell size of 10 meters. My first attempt was to download a TBDEM dataset from USGS ...
1 vote
0 answers
206 views

How do I overlay vector data over a 3D terrain basemap?

I would like to create a map that is similar to the one found here: https://www.reddit.com/r/MapPorn/comments/lpo557/geological_map_of_north_america/ . I'm thinking that you could replicate this with ...
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1 vote
1 answer
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r.slope.aspect grass gis datum format on dx and dy analysis

I'm performing terrain analysis due to photovoltaic installation on QGIS with r.slope.aspect plugin. I'm interested in evaluate differently N-S slope and E-W slope based on the PV system I would ...
1 vote
1 answer
686 views

Terrain Ruggedness Index (TRI) calculated in QGIS is approx 4 times that calculated in GDAL

When I calculate TRI using QGIS and GDAL tools for the same elevation DEM, I get results that are comparable between the two except that the absolute values in QGIS are approximately 4x that in GDAL. ...
0 votes
1 answer
70 views

Selecting Terrain Dataset by elevation in ArcGIS Pro

I have added the Terrain Dataset to my project in ArcGIS Pro. I would like to select the areas which have an elevation above some threshold. Eventually, I want to use this selection as a clipping mask ...
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2 votes
0 answers
203 views

NA values as result from Grass functions (r.slope.aspect, r.sim.water) in R

As the result from r.slope.aspect I get a raster with only NA values. r.param.scale works, but doesnt generate dx and dy maps, which I both need for r.sim.water function. Code snippet 1 (initialize ...
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3 votes
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297 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 ...
2 votes
3 answers
188 views

Terrain aspect similarity

I have a point data set with terrain aspect at the location of the points, measured in degrees. I want to compute the similarity of aspect between the points, e.g. 70° is similar to 90°. This is ...
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Lidar Dataset for Toe and Crest Detection

I have read a paper on Terrain Toe and Crest Feature Detection and Labelling forAutonomous Mining and started working on building the code for this. But I am unable to find the dataset used in the ...
2 votes
0 answers
299 views

Extract terrain coordinates as seen from a viewpoint + FoV in a digital globe

Context Every one working with photogrammetry or 3D knows what a depth image is. For example OpenCV defines a "depth map" from a stereo pair, e.g.: where the darker a pixel is, the greater ...
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1 answer
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How do you export a 3d-model in QGIS to a file that can be read in Rhino?

I am really new to QGIS and haven't really gotten familiar with all the functions yet. I've made a 3D map/model in QGIS, and would like to export this in a file format so that I can use it as a ...
0 votes
2 answers
766 views

ee.Terrain.slope() output at wrong resolution after DEM mosaicking [closed]

I'm using the Google Earth Engine JavaScript API to do a terrain correction on Sentinel-1 imagery, as in Andreas Vollrath's work. However, I want to use a higher-resolution Canadian digital elevation ...
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2 votes
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Using ArcMap to build a Terrain DEM that looks exactly the same as a TIN built from the same point shapefile

I am attempting to replicate DEMs previously constructed as TINs in the Terrain format. Building a Terrain and a TIN out of the same point shapefile produces two maps that look extremely similar, but ...
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2 votes
1 answer
946 views

Getting from a USGS historical topographic map to a Unity terrain heightmap

Is it possible to start from a USGS historical topographic map and get to a Unity terrain heightmap? To see an example of the kind of historical topo map I am talking about: Go to: https://ngmdb....
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1 vote
0 answers
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Define Terrain/Elevation textfile data format

I have a program that can visualize terrain/elevation data but will only recognize files in the below format. It has the extension .map but it is not recognized by QGIS or GDAL so I believe it may be ...
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1 vote
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How do I "flood" a terrain in Cesium to represent a high water level

I am thinking about using a plane object to represent a water level by rendering it as a certain height above ground using Cesium. Is there any example code that
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3 votes
1 answer
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Creating contour lines from DTM in PostGIS

Is there any possibility to compute contour lines from a raster DTM directly in PostGIS on a PostgreSQL database? I have only found this solution based on points "Fast contour lines using plain ...
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