Questions tagged [slope]

Use this tag when asking questions related to slope analysis.

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21 views

Correcting forestry acreages due to slope to get actual acreages treated [duplicate]

I came up with a process to get actual acreages vs map acres of steep slopes, but I am wondering what others do to correct for steep slopes and get actual acreage treated? For mine, In ArcGIS Desktop, ...
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1answer
31 views

Calculating average slope using ArcGIS Pro?

I want to rate for ease of walkability for one track, I have a road shapefile and raster of the slope. Any ideas about how to calculate average slope or other methods to do that?
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1answer
33 views

Which layer for least cost analysis?

I'm new to least cost analysis. I have a DEM-layer of a region and I want to know what's the least cost path from a to b. Do I have to use the DEM layer to calculate that? I also have a hillshade ...
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23 views

Seeking DEM for Northern England to produce slope map?

I'd like to make a slope map of northwest England (the Yorkshire Dales, to be exact) that can be used with a 3D viewer such as Google Earth to identify slopes that are steep enough for paragliding. A ...
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2answers
53 views

Labeling DEM or slope layer with slope angle in degrees?

I have a shapefile and made a DEM raster to create contours and slope analyze puttinggreen for a golf area . I have all i need except the slope values in degree (labeled directly in the map along with ...
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1answer
54 views

Digital Terrain Analysis - Roughness Index [closed]

Currently I am working on a project dealing with terrain analysis based on a DEM. I came across the term "roughness index" using slope values from that specific DEM. On YouTube I found a video, which ...
2
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0answers
39 views

Calculating variable buffers using slope between river and point 100' away using ArcGIS Pro?

I have a network of streams that I need to buffer based on a basic rule set. This buffer will depend on the slope. The slope is determined by the looking at the difference in elevation between a ...
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0answers
36 views

Extract longest flow path in ArcGIS pro

I did calculate Hydrology with Spatial Analysis tools==> Hydrology and now, I have streams and Watershed. In each watershed, I need to extract the longest Flow as a polyline for calculate slope. What ...
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0answers
36 views

Python error on QGIS

We are doing the slope analysis for one of our clients and can find the following error every time we do the analysis. We have not faced this situation in the past. The QGIS version which are using is ...
3
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1answer
157 views

GRASS GIS producing different slope than GDAL?

When producing a slope in GRASS GIS 7.4 the results are different than with QGIS (GDAL) and ArcMap for the same input data and same parameter (Z ratio is 1.0 and degrees). QGIS and ArcMap generate ...
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0answers
22 views

Selecting Certain Slope Class That Is Not Surrounded Narrowly By Other Class

not sure how to brake it down, but let me try i've created a slope classification with this class now what i'm looking for is how can i select the class of 0%-8% that is not surrounded narrowly by ...
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2answers
88 views

Adding slope values to attribute table (QGIS 3)

I have a DEM raster and some points (one .shp for all points) plotted on it. I would like to know if there is a way to add the slope value of the pixel that each point is located in the attribute ...
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1answer
76 views

Using QGIS 3.2 to add slope and/or % grade to county-wide street layer?

Using QGIS 3.2 what is the best way to add slope and/or % grade to a county-wide street layer using the following data: Streets (polylines) = 35k records (10mb) Contours (polylines) = 500k records (...
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0answers
50 views

Extracting slope of aspect information using QGIS?

In What is SOA (slope of aspect)? @Spacedman explained to me what SOA means. Now I need help to understand how I could work with it and extract the data that I want. I want to use Qgis (with Grass ...
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1answer
51 views

What is SOA (slope of aspect)?

I’m reading an article that the authors talk about extracting values of SOA (slope of aspect). I can’t find anything related to that on Google. This article reference is : ZHOU, Yi et al. Automatic ...
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1answer
97 views

Finding glider reachable area / catchment area with custom slope?

I'd like to produce maps for gliders in mountains. I'm looking to display the reachable area by a glider taking off from a given point (obviously with the corresponding DEM). For a first approach I'...
1
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1answer
59 views

Identifying flat-ish hilltops in a DEM?

I am working on a project where I need to identify the area of a hilltop that is relatively flat within which stone structures could be built before the slope becomes too great to build without having ...
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1answer
69 views

Seeking CSMapMaker (QGIS Plugin) equivalent for ArcGIS Desktop?

I'm looking for a tool or script or set of operations to mimic the output from a certain QGIS plugin called CSMapMaker, wherein curvature, slope, and a gaussian filtered DEM are overlain one another ...
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35 views

Performing raster analysis using Arcpy - in_memory does not preserve raster shape

I am creating a script tool using Arcpy and it transforms elevation data into a final clip polygon as part of a lengthy site selection tool. When I perform the raster analysis and save my intermediate ...
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1answer
35 views

Slope is not consistent with the elevation of DEM and seems to be incorrect

I have a DEM image which shows the elevation is from approx. 81 to 103. I expected the slope should be 0-22m. However, the result from DEM-Terrain Model-Slope is from 2.5 to 13.2. Anyone knows why?
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65 views

GdalDEM slope error in Jupyter

I try to calculate slope data. This is the DEM source https://www.earthenv.org/DEM Firstly, I translate data with gdal.Warp according to image UTM zone. Original image .bil extension so first I ...
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1answer
65 views

Estimating slope by fitting a quadratic surface (Evans 1980) in ArcGIS Pro

I am needing to calculate slope using the quadratic surface method of Evans (An integrated system of terrain analysis and slope mapping, 1980), but not sure how to implement it in ArcGIS Pro. A GRASS ...
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1answer
176 views

LS Factor in SAGA (slope units)

In which units do I have to calculate Slope to use as an input for the LS Factor tool in SAGA (degrees, %, radians)? I couldn't find anything in the documentation.
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1answer
84 views

Strange output from QGIS Raster Terrain Analysis plugin

This is closely related to several other questions on this site: here, here, here etc. However, my issue is not resolved by following the answers provided. I am using the Raster Terrain Analysis ...
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0answers
65 views

Calculating maximum extent of debris flow from point with mean slope value

At a very large scale I perform a spatial analysis for which I have to apply mean slope criteria. These criteria allow me to calculate the maximum extent of an event (debris flow). I know that below a ...
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1answer
178 views

How should I interpret R terrain/slope output in degrees?

I'm calculating the average land gradient (in degrees) in Brazil and I do not know how to interpret the results. As I'm calculating the slope in degrees, 0.25 is 0.25 degrees, 25 degrees or should I ...
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1answer
40 views

Creating slope map with ArcGIS Desktop?

I created slope map with DEM model in ArcGIS Desktop. But it is only categorize in to two sections. I think it is problem with the horizontal and vertical scale. I used WGS84 coordinate system. How ...
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0answers
16 views

Calculate average slope values for a point using 50ft vector perpendicular to contour

I am trying to calculate the average percent slope of a hillside on either site of a data point. I tried extracting info from a DEM using a radius around the point, but I believe a more accurate ...
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1answer
112 views

Statistics of slope in individual polygons (asset) on Google Earth Engine

I have a single shapefile with multiple polygons, uploaded to GEE as an asset. I am trying to find the mean slope (using SRTM elevation imagery) in each of the polygons, on GEE. However, I get only ...
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0answers
56 views

Slope rasters - different results from different tools

I'm calculating Least Cost Path (LCP) within QGIS 2.18. The first step is to produce the slope raster from the DEM. Using r.slope in GRASS produces excellent results where I can go on and finally ...
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1answer
45 views

Convert slope file to calculate the percentage of the coverage

I calculated the Slope of the area that I'm working on, and I was wondering if there is a way to calculate the actual percentage of each bracket, meaning the percentage of contribution of each class. ...
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1answer
84 views

Converting RTK Elevation Data to DEM?

I have a shapefile that contains elevation data. I want to eventually convert this to a slope layer. I'm assuming I have to convert to a raster, then a DEM, then slope. Is that correct? If so, ...
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0answers
21 views

QGIS/GRASS: forecast slope variation in slope by a new road

For preliminary project purposes, I wonder if there is a way to forecast and calculate with QGIS and/or GRASS the variation of slope dued by new road, starting with terrain DEM and a project sketch of ...
2
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1answer
83 views

What the default unit in QGIS 2.18 $area is calculated and etc?

I'm a beginner in QGIS . We are using 2.18 version. What are the basic units for area and slope, etc? SI, so means m, m^2, °? Or I can set it by myself? If it's possible to set it, where?
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1answer
406 views

Creating polygons of specific slope percentage from a slope raster in QGIS

I am trying to extract all areas where the slope is greater than 20% and then turn those areas into a polygon. I'm using QGIS 3.0.2.
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1answer
82 views

Service Area (ArcGIS), including slope as a cost

I'm trying to make a service area network analysis containing the time that is needed using a bike starting from one point. The attached map shows this service area when the bicycle speed is 20km/t, ...
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1answer
857 views

Calculating slope/gradient from longitude and latitude

I've recently got some field erosion data. The only geographic data I have is the (lon, lat) (in degrees). I need to plot the erosion against the slope, however, I do not have the slope yet. Is it ...
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0answers
187 views

QGIS - Lookup elevation or slope from geoTIFF from a series of lat/lon values

I have a geoTIFF file (pretty large) covering a good chunk of Spain around Almeria. I got it from the EU-DEM v1.1 data (25m resolution), freely available in which I have a route in lat/long and I want ...
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0answers
91 views

Edit a raster (DEM) to create a constant slope angle

I'm trying to edit a raster (DEM) that has square sides (90 degrees) to create a surface with a constant slope angle of 18 degrees. I'm working in QGIS and have not been able to find any help for ...
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1answer
28 views

Unwanted artefacts working with Raster analysis

I am trying to make a simple slope map from a DEM (tif). I already tried with the different slope-tools in QGIS (GDAL, SAGA, GRASS) and also the 3D Analyst in ArcMap. Boths bring the same result: a ...
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1answer
18 views

How to define the angle of points on slope?

I have point data set and DEM and my task is to identify how many points are falling on the slope of more than 40 degrees. How could I do this in ArcMap?
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33 views

Why is my aspect not displaying the full data?

I am trying to get the slope aspect for the altitude shown above. Can someone please advise me on why this may not be working properly?
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2answers
347 views

Issues with QGIS Slope Analysis

Having issues with slope analysis. I click raster, analysis and then slope. I enter my input and output and run the tool. The output I get doesn't appear to have been calculated correctly. Instead of ...
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1answer
83 views

Generalizing slope raster in Mapinfo?

I am working on calculating a slope raster in Mapinfo using a 15cm DEM derived from a LiDAR point cloud and the output data will have 3 predefined breaks displayed so I need to blur those relatively ...
0
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1answer
281 views

Slope Classification for HRU in a watershed (SWAT Model)

For the definition of HRU (Hydrological response units), the parameter slope can be classified into maximum of 5 classes. Depending on the definition the results will vary. Is there a commonly used ...
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1answer
155 views

Changing DEM resolution when creating a slope raster? [duplicate]

I want to create a slope map using a LiDAR DEM. I think that I should use the slope tool; but I need a slope map with a 2m resolution and I'm not sure how to do that. How can I have a slope map with ...
0
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1answer
48 views

Slope and mosaics

I have used a large number of Gtopo30 altitude tiles and used the mosaic tool to create a large DEM for my area of interest. I am trying to get a slope for said area but when running the slope (...
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1answer
73 views

How to create a surface with a slope of 2%?

I am working on a project where I have a polygon of a basin that I should create his base whose elevation begins at -1m and go down in every direction with a slope of 2%. Does anyone know how to do it ...
2
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0answers
84 views

QGIS: How to find a line with defined slope starting from a point over a DEM? [closed]

If I have a DEM as raster layer and a point with defined position in a point layer, how could I generate a line with defined slope of e.g. -1%? The end point can be anywhere and should be defined by ...
0
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1answer
108 views

Selecting a subset of a raster, based on aspect and slope, as input to calculate area

Background I created some digital elevation models and subsequently made a 2 layer raster for each containing the calculated aspect and slope using raster::terrain. Now I want to calculate the area of ...