All Questions
77
questions
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 ...
- 95
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 ...
0
votes
1
answer
100
views
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 ...
- 147
0
votes
1
answer
1k
views
GRASS function r.fill.dir not working on specific DEMs
I'm using QGIS. The function r.fill.dir is not working on a few DEMs I'm working with. With other DEMs, it works. I attached the log report and one of the troublesome DEMs. You can see my QGIS ...
0
votes
1
answer
186
views
Correct measure unity for slope and aspect in order to work in QGIS with "r.sun.insoltime"
I'm using QGIS 3.10 and I should create a raster that shows the hours of sunlight referring to a given day for my province. r.sun.insoltime (Fig. 1, sorry it's in Italian but I traslate) to work asks ...
- 23
3
votes
1
answer
516
views
Extracting peaks and cols from a DTM raster and convert them into point shapefiles (QGIS)
I’m trying (again) to find an automatic way to extract peaks and cols from a DTM raster (derived from LiDAR surveys).
By “peak” I mean simply the cell with the highest value of a neighbour of cells;
...
- 339
1
vote
0
answers
490
views
r.fill.dir not working
I am using QGIS 3.16.2 "Hannover" with GRASS 7.8.4 on Windows 10 64 bits.
Im doing a watershred and r.fill.dir is not working, the message is the common the following layers were not ...
- 55
0
votes
1
answer
34
views
Identifiying the levels for streams derived from DEM
I am using GRASS GIS and I have been able to identify the various water-flow channels / streams using the documentation from r.watershed.
Now I wish to identify the levels of the streams. For example, ...
- 318
2
votes
1
answer
503
views
Denoise/smooth DEM in GRASS GIS using r.denoise addon
I'm trying to denoise/smooth a digital elevation model (TIFF) file on GRASS GIS using r.denoise add-on. I cannot get it to work.
I don't know what to enter in the output box, my goal is to create a ...
- 21
1
vote
0
answers
142
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 ...
- 841
2
votes
0
answers
86
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 ...
- 21
1
vote
1
answer
285
views
Extracting contours from .jp2 DEM dataset
Problem:
I have received a data set from a municipality that is a 3-layer LiDAR JP2 DEM and need to extract ground contours at 1 m intervals for a specified area (more below).
Programs available:
...
- 19
2
votes
0
answers
395
views
Create shadow mask from DEM using QGIS
How do I create a shadow mask based on a DEM, with the sun conditions (azimuth and altitude) known?
I am using QGIS, and had hoped to use the r.sunmask.position tool for this. The DEM is in UInt16 ...
- 29
2
votes
1
answer
79
views
Calculate cost of predefined path
I am trying to calculate the cost of walking a predefined path. The path can be a line or a number of points along that line. I have a DEM and derived it's slope, which I will use as a friction map. I ...
- 518
2
votes
1
answer
1k
views
Line of Sight between sets of two points each
So I have a list of points with their longitude and latitude (Lon_A, Lat_A and Lon_B, Lat_B). I also have a DEM layer from the SRTM for the relevant location. I need to check if line of sight exists ...
- 783