Questions tagged [slope]
Use this tag when asking questions related to slope analysis.
368
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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 ...
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Auto generation of a line of predetermined % grade across a raster DTM using QGIS or Whitebox GAT
I have used QGIS for the purpose of trail routing through relatively steep terrain, often ranging from 45-60˚ slope. I have achieved fairly accurate routing of desired trail alignments at 15-20% ...
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39
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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 ...
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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/...
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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 ...
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86
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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 ...
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61
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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 ...
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Find the highest slope in a radius measured out from a line QGIS
I was wondering whether there is a process in QGIS to finding the largest effective slope (rise over run) measured from any point along the frontage of a building envelope (or polygon) over an area ...
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36
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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 ...
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34
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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 ...
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Classify faces of steep vertical slopes using point cloud as input
I’m trying to develop a tool for slope risk analysis with 3D models like showed in the image below. In this 3D model, the slope faces oriented in the same direction and with the same inclination have ...
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54
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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, ...
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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 ...
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76
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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 ...
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301
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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 ...
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51
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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 ...
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32
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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/...
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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 ...
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52
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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 ...
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140
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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 ...
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31
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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 ...
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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 ...
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57
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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 ...
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56
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ArcPy code producing slope map with wrong values
When I run my Python script in ArcMap it produces a slope map just how I want it, but it's producing it with the wrong values. The slope map produced by the script is the one named "reclass.tif&...
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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). ...
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13
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Randomly faulty Northslopes with Raster Calculation in (Py)QGIS
So I am trying to calculate all Northslopes in the Area of the .tif files.
When I do it manually with the raster processing tool within QGIS it's only working sometimes, when I use the attached Python ...
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31
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Using reclassify method from ArcPy to set range of slope map
I'm having a bit of trouble with the syntax and some of the parameters for some functions in ArcPy (I'm completely new to it and struggle with the documentation quite a bit). Specifically, I'm trying ...
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80
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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 ...
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57
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Assumptions of Slope/Aspect Formulas
I've coded up an implementation of Wood (1996) slope/aspect algorithm via quadratic fit as well as a modified version of the traditional ArcGIS planar slope algorithm that can use window sizes other ...
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53
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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.
...
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79
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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?
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66
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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 ...
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14
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Using ArcGIS path distance tool and vertical factor to estimate fuel used by automobile
I am attempting to use the Path Distance tool (either in ArcMap 10.7 or ArcGIS Pro 2.8) to estimate the amount of fuel vehicles need to drive across the landscape. I have the typical gas mileage/fuel ...
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233
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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 (...
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Problem with gdaldem slope -> result is off by some degrees
We are currently having some issues with gdaldem slope. We'd like to create a slope map of a geotiff, but the result seems to be some degrees off to what it actually should be.
Our input geotiff is in ...
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''pixelatted'' ''griddy'' result from slope function (QGIS) [duplicate]
I use the SRTM downloader to download my DEM's, then it happens very often that when I create a slopemap there are weird artefacts in the slope map. Something I do before making the slopemap is ...
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170
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Draw buffer around points considering slope in QGIS
I generated random points on a map. Around each point I would like to draw a circular buffer which considers the slope in that area, and within these circular buffers I would monitor tree height in ...
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69
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Calculating area of polygon with consideration of slope in QGIS [duplicate]
I would like to know if there is an easy/efficient way in which you can calculate the area of a polygon considering the irregular slope underneath the polygon. I would like to know a solution in QGIS.
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82
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Raster calculator does not show right result ( only show true)
I am using ArcGIS 10.5. From a DEM, I have created a new raster showing slope using the slope tool. The colour scheme was automatically classified into 9 tiers. What I want to do is query this raster ...
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186
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Raster Calculator in processing scripts crashes using PyQGIS
I am currently writing a processing script for QGIS that goes as follows:
Takes in a digital elevation model (DEM) tiff file, a shapefile mask of the study area, and a slope cutoff value in percent
...
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113
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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 ...
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148
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Correct format for slope and aspect in order to work in QGIS with "r.sun.insoltime" [closed]
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 ...
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209
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QGIS slope output problems
I've been trying to calculate slope in percentage for a project I'm working on but keep running into this issue
Whenever I calculate slope using the designated Slope tool or the r.slope.aspect tool I ...
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108
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Weighting the flow accumulation raster by the slope raster in QGIS
I am trying to represent de equation of Mahoney et al. (2018)
https://www.sciencedirect.com/science/article/abs/pii/S0022169418302877
Where Si is the slope in the cell i, ΣSup is is the sum of the ...
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152
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Bad result when extract slope from HGT using GDAL
I'm trying to generate a slope tif from a HGT DEM file from SRTM.
I'm following this posts:
https://blog.mastermaps.com/2012/06/creating-hillshades-with-gdaldem.html
https://blog.mastermaps.com/2012/...
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684
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Calculate 3D area with an DEM in QGIS
I have a lot of my projects that are located in mountains. When I draw my polygones, I can easily calculate $area, of course. But in many cases, I underestimate the surface of my polygons due to the ...
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Relation between Solar Radiation and Elevation: Satellite Data
I used DSR (Downward Shortwave Radiation) data from MCD18A1 product and GHI (Global Horizontal Irradiation) data from SOLARGIS to create solar maps:
Using this elevation map:
I see that the solar ...
2
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1
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533
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Converting a degree slope raster to a percent slope raster, without a DEM, using raster calculator
I've been given a raster of degree slope which I need to convert to percent slope. As the original DEM is not available and those who provided the raster want me to work with this one, I have to ...
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28
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Plotting polyline trail using slope raster with least change in slope and ArcMap [duplicate]
How do I plot a trail in ArcMap so that it runs from point A to point B?
This is part of a larger model I am working on that takes various variables into account and creates a cost layer that I then ...
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138
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Highlighting slope in QGIS
I created the slope layer in QGIS through "Raster > Analysis > Slope" and then used the function in GRASS r.slope.aspect, but how do I highlight a slope of 0° degrees to 60° degrees? I ...
