Questions tagged [slope]

Use this tag when asking questions related to slope analysis.

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Gradient Vector From Surface tool applying arrows to entire map instead of clipped area

I can't figure out why 'Gradient Vectors From Surface' started applying the arrows to the entire map instead of just the clipped area as it had when I started using the tool (see images).
Cwallipers's user avatar
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30 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://...
user197410's user avatar
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60 views

QGIS Slope: Slope processing tools not working as expected using DEM

I have a NRCS 2M DEM Bare Earth file for which I have already successfully applied the Hillshade and Aspect tools in my QGIS v3.34.1 project (see below). Now I am attempting to determine slope using ...
Linus's user avatar
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2 votes
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48 views

Calculating dredged material volume with sloped trapezoidal geometry using bathymetric data in QGIS

I have bathymetric data (as a point layer) for an area slated for dredging, where the target depth is -4m relative to Chart Datum. I have a polygon outlining the dredged area. The post-dredging ...
icru's user avatar
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46 views

QGIS and percent values in slope map

I create a slope map from a DEM downloaded with SRTM Downloader in QGIS 3.32.0-Lima. I searched in the internet trying to find the way to interpret the values of the left column in percent. For ...
Joseph's user avatar
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54 views

Cross-slope of a trail in ArcGIS Pro

I am trying to make an accessible map that includes the typical and maximum slope and the typical and maximum cross slope. I understand how to determine the elevation profile of the trail, but it is ...
Deb Innes's user avatar
2 votes
1 answer
96 views

Generate shortest straight path between points and a given elevation in QGIS

I'm trying to do terrain analysis in QGIS. I have a vector layer with equally spaced points along a slope, and these points are somewhat parallel to the coastline of a fjord: I'm interested in ...
Will's user avatar
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29 views

Calculating MESO-scale slopes from a DEM

I have a coastal DEM which I want to use to calculate the cross-shore slope with ArcGIS Pro. In the image below I've plotted the zer and five meter contours, and what I want is to calculate the ...
anner.paldor's user avatar
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141 views

How to interpret values of elevation standard deviation statistic (and not elevation mean) from DEM

I am trying to interpret the standard deviation of elevation to understand the topographic landform of my study area. We have 2km*2km grids in the study area for which we extracted certain landscape ...
RashmiSRana's user avatar
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55 views

Adding slope to lines drawn using PyQGIS

I want to add a slope to lines drawn using PyQGIS. The lines drawn with PyQGIS are currently green, but I want them to appear brown. How can I achieve this? The code I wrote: import math from qgis....
BrsDltV's user avatar
1 vote
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54 views

QGIS Profile Tool - creates inaccurate profile

The profile created by the plugin is inaccurate (the vector is traced over a river and therefore the line should never move upwards in elevation). When I hover my cursor over the produced profile, the ...
Justine's user avatar
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28 views

Identical values of bathymetric data

I downloaded gridded bathymetric data from GEBCO, from which I calculated a slope map using QGIS and then examined the resulting values using the 'raster layer unique values report' function. I found ...
br0wnb4n4n4's user avatar
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54 views

QGIS Least Cost Path Analysis taking forever

I have been trying to calculate the Least Cost Path (LCP) between two points on my map. These points are approximately 100km apart. I have created a slope from my DEM raster, created proper vector ...
Brittany's user avatar
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1 answer
207 views

3D surface area with Google Earth Engine

I have my region of interest as a polygon. When I calculate the surface area I get a '2D value' (ie as if it was a flat surface). The problem is, the region is quite full of hills, so the real surface ...
terauser's user avatar
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55 views

What is the hatch marking of my produced terrain slope raster?

I’ve been piecing together DEM raster data from different sources, in an attempt to create a terrain slope raster. I’m using ArcGIS Pro to merge the DEM’s together and then using the split raster tool ...
Whitney's user avatar
3 votes
1 answer
217 views

Getting x, y, slope in raster, using QGIS

I'm the new to QGIS. I have a slope raster that was made by using DEM 5m (also that was made by using contour 5m shp file). How do I get a txt(or csv ...) file containing [x, y, slope] data? I used '...
thisLecture's user avatar
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62 views

QGIS how to export slope data with x, y

I have a shapefile with contour line data, that looks like the following: Columns 1, 2, 4, and 5 are geometric data and column 3 is contour data. (MultiLineString type) First, I tried 'TNI ...
thisLecture's user avatar
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39 views

Units of slope output

I am calculating the slope from the DGM file which is of 1m spatial resolution. The default CRS is ETRS89 33N 25833 for that particular piece of land in Germany, kustriner vorland. In what units are ...
SUBHASHISH KAUSHIK's user avatar
0 votes
1 answer
269 views

Google Earth Engine - slope

I am trying to use the pre-built function of GEE for calculating the slope of the terrain, but I cannot really understand how the function works, since the documentation is also not really helpful. ...
Gaiagruu's user avatar
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2 answers
69 views

QGIS Report Slope Results

How could I report information about a raster result? In this case I have done slope analysis, and have reclassified it into 5 values for particular slopes. Now I am wondering if I can report ...
Jed C's user avatar
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2 votes
0 answers
69 views

Distort buffer on slope direction in QGIS [closed]

I'm an archaeologist and an average QGIS user, not advanced at all. I'm studying a method for the mountain archaeological contexts. My aim is to define some influence areas around the sites and ...
ugoposcolo's user avatar
2 votes
1 answer
96 views

Network analysis (with slopes)

Using the QGIS network analysis (layers) command, I can calculate the maximum areas that a "bus stop" point can serve by determining a distance X. However, I would like this distance to vary ...
Pedro Coelho's user avatar
3 votes
1 answer
251 views

What value does slope represent, how is it calculated from neighboring cells of a raster DEM?

In QGIS, I have a Digital Terrain Model. Using Slope (Menu Raster > Analysis > Slope..., in fact using GDAL Slope algorithm), I get an output raster, either in percents or degrees, the same ...
Babel's user avatar
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3 votes
1 answer
292 views

Calculating slope using the 3*3 window approach for elevation data

I have some DEM grid data (25x25, 625 pixels) and I am trying to figure out the correct formula for calculating slope for each pixel. Some googling gave me a bunch of different formulas, but I've ...
frodolicious's user avatar
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48 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 ...
Martin Málek's user avatar
0 votes
1 answer
95 views

Determining slope percentage using ArcMap

I am working on a project where I need to conduct a MCA. One of the criteria is: if the slopes are greater than 15%, they should not be used at all. I have DEM model and a slope has been made in ...
Afnan Askar's user avatar
7 votes
2 answers
779 views

Drawing slope signature in QGIS

I would like to have a slope signature (in German "Böschungsschraffen") like this : https://bauforum.wirklichewelt.de/index.php?id=9672 (German) https://www.akgsoftware.de/docs/de/...
MartinMap's user avatar
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0 votes
1 answer
100 views

Building roads on steep slopes with QGIS [closed]

I work in forestry and want to get QGIS to generate a vector line that doesn´t exceed a certain road slope. I can get it to tell me what the slope is on a road I draw myself, but how can I just insert ...
Philip's user avatar
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1 vote
2 answers
221 views

Slope calculation with datasets in different CRS

I have a shapefile containing several zones. This file is in CRS EPSG:32644 (WGS 84 / UTM zone 44N). I have a DEM file (originally in CRS EPSG:4326 - WGS 84) that I converted to EGM08. The elevation ...
ParcoMolo's user avatar
1 vote
0 answers
169 views

How to calculate exact slope and aspect for a polygon

I want to calculate the aspect and slope for polygons, because they appear as fruit-growing areas. I got the DEM 1m for my datas and calculated aspect and slope with the QGIS functions. Then I ...
Micha's user avatar
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0 votes
1 answer
75 views

Getting watershed area corresponding to each erosion severity class for each slope class in ArcMap

I’m new to this. I have two (watershed) rasters: soil loss (erosion) by severity; and slope. For each erosion severity class (listed below), I would like to obtain the watershed area that falls under ...
Kevin Durant's user avatar
1 vote
1 answer
44 views

How to switch expression generated line sections in QGIS?

According to this thread about "Changing length of Shortest_Line for CAD-like slope pattern using QGIS" (https://gis.stackexchange.com/a/386104/212966) I would like to learn how to switch ...
pvosz's user avatar
  • 21
1 vote
0 answers
98 views

DEM to Slope in QGIS 3 [closed]

I'm having trouble with the slope of this particular DEM (USGS_13_n33w097_20211124). The file downloads correctly and presents the elevation values in QGIS, however after running the QGIS Slope tool, ...
greyhug's user avatar
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1 vote
0 answers
58 views

Slope Angle between vertices using QGIS

I am trying to work out whether a center pivot irrigator (you may have to google this to see what they look like) has too much angle between the spans as it goes over hilly terrain. I can generate ...
Luke Taylor's user avatar
1 vote
1 answer
147 views

Computing slope using QGIS

I want to compute the TWI (Topographic Wetness Index) for my study zone (SZ) using a DEM that I reduced to my SZ (SZ_DEM, https://www.mediafire.com/file/46vr8r4pbl2vpol/SZ_DEM.tif/file). The first ...
Germain Vital's user avatar
0 votes
1 answer
2k views

Average slope (in °) for each area

I have nationwide areas I want to get the average slope in ° in a south-north line for each area. I found something about zonal statistics in QGIS and DEM (enter link description here) but returns ...
BAE_23's user avatar
  • 601
0 votes
1 answer
115 views

Accuracy of LIDAR from XYZ and DEM comparison

I'm taking point cloud xyz's from LIDAR and turning them into DEMs, then comparing that DEM, to a DEM of the original 3D CAD Models to see how well the LIDAR is measuring the model for elevation and ...
Rudift's user avatar
  • 1
0 votes
1 answer
48 views

ASTER DEM, Incoherence of slope analysis

I'm using a Aster tile DEM to perform some terrain analysis on an area in the French alps (original CRS:EPSG 4326-wgs 84), using QGIS 3.2. My projected coordinate reference system is EPSG:2154-RGF93/...
Agnese Marcigliano's user avatar
0 votes
1 answer
25 views

Steep cropland selection using ArcMap

I have: a raster file of land cover classes, the classes are urban, bare land, forest and agricultural land. a have a DEM, from which I can calculate the slope classes. No I want to assign a new ...
Prayon's user avatar
  • 1
0 votes
0 answers
82 views

Creating slope map from DEM of Lunar South Pole

I've managed to create slope maps from other DEM's without much issue, but this DEM seems to have trouble and only does the very top section, with the rest being an error. I am very much a beginner in ...
Rudift's user avatar
  • 1
4 votes
1 answer
196 views

Number of pixels Elevation - Aspect - Slope

I have a DEM, resampled at 100 x 100 and clip by mask with a polygon. Unique values report give me Total pixel count: 733810 with NODATA pixel count: 427098. Aspect and Slope map give me the same ...
Kostas Pl.'s user avatar
1 vote
0 answers
42 views

Incorrect Z Value in Slope and hillshade Raster from QGIS

I have to create a TIFF for hillshade and Slope from data obtained by Eiva software, basically a XYZ file. When I drop in the XYZ or TIFF exported from Eiva and try to create the layers they seem ok ...
Andrew Laverty's user avatar
0 votes
0 answers
25 views

Changing labels and colors of slope map values in ArcPy with ArcMap

I have this code in ArcMap which produces a slope map with the correct values (the slope map is reclass.tif), but I want its labels that appear in the Table of Contents underneath it to show ...
Darell's user avatar
  • 45
1 vote
1 answer
99 views

Calculating terrain attributes before or after upscaling DEM

This is more of a theory question. I am working on a project that requires the use of topography data, I have a 1KM resolution global DEM to which I will be using GDAL to calculate general topography ...
JP Crossley's user avatar
2 votes
0 answers
37 views

ArcPy producing wrong slope map using Spatial Analyst with ArcMap

I wrote a Python script which is supposed to produce a slope map with 6 classes each one being from 0-3.99, 4-9.99, 10-15.99, 16-30.99, 31-60.99, 61+ (Although for testing purposes the max is 789.54). ...
Darell's user avatar
  • 45
0 votes
0 answers
207 views

DEM raster scale incorrect after running slope analysis QGIS

Working with DEM rasters from TNM 3DEP elevation data and trying to create a percentage slope map in QGIS. I added my rasters and tried running both the gdal slope that allows for % slope and the ...
user207315's user avatar
0 votes
0 answers
89 views

Getting percentage of parcels covered by slope polygon file using ArcGIS Pro without using Identity?

I've read the other similar stack questions and they weren't helpful, as in the processes didn't work or there was some ambiguous field references that may have contributed to my confusion and error. ...
Scott Jordan's user avatar
0 votes
0 answers
131 views

Negative slope in QGIS

How do I use the QGIS slope function to calculate slope and differentiate between uphill and downhill, and produce both positive and negative slopes?
Yishai Friedman's user avatar
1 vote
0 answers
175 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 ...
Flexalo's user avatar
  • 11
2 votes
0 answers
422 views

QGIS Raster Hillshade Classic Drawing Texture

I found this drawing of a valley and really like the texture of it. I suppose this is a sort of hachure map drawn with dots. I was wondering if it was possible to recreate something similiar in QGIS (...
Mecky's user avatar
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