All Questions
98
questions
0
votes
0
answers
54
views
Using DEFRA LiDAR dtm-1m to calculate slopes etc in QGIS
I have a shapefile of woodland polygons and want to calulate slope and slope orientation of the polygons.
I am using the LiDAR Composite Digital Terrain Model (DTM) - 1m in QGIS. Available at: https://...
- 41
3
votes
2
answers
404
views
Creating topographic "layer cake" map a.k.a. Tanaka contour in QGIS
I'm wondering if there is any way to create a map similar to the image below. Basically, it would be the contours extruded, add a singleband pseudocolor ramp as the color on top, and be able to ...
2
votes
0
answers
125
views
Plotting Mean High Water Mark from DEM LiDAR around mangrove vegetation
I am currently trying to plot a Mean High Water Mark (MHWM) using a 1m DEM created from LiDAR. I have been able to plot a contour value representing MWHM based on tide gauge data. When I create the ...
- 21
0
votes
0
answers
75
views
Contour to DEM interpolation
I am using the Topo to Raster tool to convert contours to a DEM, the DEM is ~90% accurate, however in some locations in the DEM the interpolation produces values higher or lower than what the contours ...
- 109
0
votes
0
answers
48
views
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 ...
- 1
4
votes
2
answers
979
views
Extract Single (or small number) Contour from DTM data in QGIS
I understand that Contour data can be extracted at particular intervals fairly easily, but have been recently mapping a number of Flood Water Design levels which are denoted to the nearest 0.001m.
It ...
- 307
0
votes
0
answers
57
views
Variable resolution across DEM in QGIS
I am try to build a contour map from this DEM but I've noticed that the resolution varies across it resulting in orthogonal contours and 'choke points' where contours are sharply forced together. How ...
- 1
0
votes
0
answers
233
views
QGIS Contour Vectors to Raster
I'm wanting to create a DEM from vector contours but whatever tool I use, it fails to identify the sea level contour at elevation 0.
I have tried via GRASS v.to.r, QGIS tool Vector to Raster and QGIS ...
- 49
1
vote
1
answer
119
views
Flipped Contour Polygons from GDAL
UPDATE # 01 : Links to related past questions:
Mirrored Contours from DEM in QGIS
gdal_translate creates images that are mirrored
This question has been asked before, but I can't fix my personal ...
- 191
0
votes
1
answer
209
views
Clean DEM in QGIS
I'm attempting to create a DEM in QGIS from contours using the "Rasterize (vector to raster)" function.
How do I create a DEM that is clean and does not have blank spots?
- 21
2
votes
1
answer
2k
views
Why is QGIS contour generating tool not working with my DEM tiff file?
First a note about previous data processing. My original data (from a LIDAR scan) is a text .asc file with the internal structure looking like this:
457758.77;110272.34;353.89
457758.77;110273.34;353....
- 123
0
votes
1
answer
123
views
Digitizing topographic contours to produce DEM from it using ArcMap
I have four topographic maps spanning 60 years all of which have the same scale (1:62,500). I have digitized contours (5 feet interval, 4 contours 285, 290, 295 and 300 feet) of the same section in ...
- 109
1
vote
1
answer
49
views
Custom contours on DEM [closed]
I've made a DEM using LIDAR, and I'd like to mark specified contours on it as polylines.
Is there a way I can create custom contours for specific heights OD?
I can use either QGIS or ArcGIS Pro to do ...
- 351
0
votes
1
answer
754
views
Is it correct to use a 1/3 arc-second DEM to make a 2 ft contour shapefile?
I need 2ft contours for all of Puerto Rico. I have downloaded 1/3 arc-second DEM on the island from the USGS. Would it even be accurate I if I just made these in ArcGIS Pro? All alternatives and ...
- 11
1
vote
1
answer
303
views
Batch Processing Contour Lines in QGIS
I'm trying to create contour lines at 40 meter intervals from 60 different DEM Contour Shaded files.
Rather than doing them 1 by 1 I have tried using the batch process but I don't get any results as I ...
- 97