1
vote
1answer
39 views

QGIS DEM (Terrain models) Mode Slope creates wrong data [duplicate]

I have a DEM raster file downloaded from the USGS site. The file can be downloaded here. I am trying to create a slope raster in percent with the DEM tool in QGIS. The GDAL command is the following: ...
1
vote
1answer
41 views

How to create a slope map with different colors according to slope percentage or degrees

I have converted a dxf file with contour lines into a polyline shapefile, and I have used the Raster Analysis plugin to create a grayscale slope map from this shapefile. I would now like to have ...
0
votes
0answers
52 views

Analyse slope gradient from LiDAR .asc data

I'm new to using QGIS. I have purchased some LiDAR data which downloads as .asc format, is there a way to analyse the terrain slope angle from this data or does it need to be converted into DEM? ...
4
votes
2answers
86 views

bicycle / bike map road grade markers - semi-automated?

So I'm making a bike commuting map for our area, and one of the features to show (common on a lot of bike maps) is some type of road grade marker. We're planning to show three categories: 'kinda ...
0
votes
0answers
37 views

qgis - slope from DEM - errors due to projection and oversimplified 'z factor' [duplicate]

I'm trying to generate a slope raster from a DEM raster. It seems there is a pretty significant error due to the 'z-factor' option. I'm fairly new to this, but some other posts and responses ...
2
votes
1answer
213 views

What angular units does the QGIS raster calculator use: Degrees, Radians, Gradians?

I am working with QGIs and am converting a slope raster with values in degrees to a slope raster with values in percent using the raster calculator and the following formula: ...
2
votes
2answers
2k views

Can I create a TIN from contours lines (shp) in QGIS?

I need to do a slope analysis, and would like to make a TIN from 2m contours lines. Or do a slope analysis directly from contours? The only DEM available is not precise enough. I do not have any ...