Questions tagged [terrain]
The vertical and horizontal dimension of land surface
230
questions
1
vote
0
answers
16
views
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 ...
- 11
0
votes
0
answers
17
views
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 ...
0
votes
0
answers
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 ...
- 1
-1
votes
2
answers
67
views
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 ...
- 386
0
votes
0
answers
16
views
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 ...
- 1
2
votes
0
answers
20
views
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 ...
- 83
2
votes
0
answers
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://...
- 141
1
vote
0
answers
41
views
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 ...
- 11
0
votes
0
answers
74
views
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 <...
- 9
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 ...
- 1,597
0
votes
0
answers
26
views
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....
- 119
1
vote
1
answer
417
views
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 ...
- 123
0
votes
0
answers
17
views
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?
1
vote
0
answers
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 ...
- 11
0
votes
0
answers
66
views
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 ...
- 1
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" ...
- 356
1
vote
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, ...
- 41
1
vote
1
answer
290
views
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 ...
- 505
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 ...
- 21
0
votes
0
answers
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 ...
0
votes
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 ...
- 11
0
votes
0
answers
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?
...
- 31
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 ...
- 21
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
0
answers
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.
...
- 9,111
0
votes
0
answers
506
views
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 ...
1
vote
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 ...
- 121
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'....
- 137
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 ...
- 23
0
votes
0
answers
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 ...
- 59
0
votes
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 ...
- 1,110
1
vote
1
answer
114
views
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 ...
- 143
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 ...
- 11
1
vote
1
answer
176
views
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 ...
- 11
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. ...
- 101
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 ...
- 111
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 ...
- 47
3
votes
0
answers
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 ...
- 31
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 ...
- 511
0
votes
0
answers
44
views
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 ...
- 9,111
0
votes
1
answer
1k
views
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 ...
- 1
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 ...
- 71
2
votes
0
answers
20
views
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 ...
- 21
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....
- 123
1
vote
0
answers
99
views
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 ...
- 11
1
vote
0
answers
109
views
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
- 111
3
votes
1
answer
596
views
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 ...
- 495