Questions related to slope analysis.

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1answer
45 views

Calculate Cumulative Distance (incorporating slope) of a Line Feature Using ArcGIS

In ArcMap, when creating a line feature class within a geodatabase, the length of each record is automatically derived upon creation. This length is based on a distance measurement for a planar ...
0
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0answers
13 views

Aspect and slope combining for pattern recognition [closed]

Is it possible to combine the slope and aspect maps so that we can delineate automatically continuous lines (linear patterns)? My example is pretty complex (statistical) aspect in left, and slope in ...
3
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1answer
25 views

Are there any tools that can identify ravines/steep elevation drops from contour line data?

I am trying to create polygons around rivers that extend all the way up to the top of the surrounding slopes. I am currently able to do this using stream data and contour data, but I would have to ...
0
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1answer
31 views

Trying to Run Slope Analysis Script

I'm trying to make a slope raster from a lot of DEM`s. The DEM rasters are in this file Geodatabase C:\Bachelorarbeit\Daten\GIs\Originale\dtk25_dgm1.gdb The slope raster should be saved in this ...
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0answers
8 views

Extract median slope percentage for a specific plot of land

I'm completely new to GIS, but I have a possible upcoming project that requires tools for assisting people assessing the bushfire safety of specific private and commercial properties. One of the ...
0
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1answer
30 views

Automatically calculate average slope of a street segment

I'd like to be able to automatically calculate the average slope of a street segment in ArcMap (start elev - end elev / length). My map looks something like this, with street centerlines in black and ...
3
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2answers
148 views

Calculate regional slope from DEM

I need to calculate regional slope for a coastline using a ~500 meter DEM covering a coastal plain and continental shelf where the slope for each grid cell is calculated by defining elevation extremes ...
0
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0answers
25 views

Slope calculated incorrectly from DEM

I am using the slope tool to calculate slope from a DEM. I'm getting values from zero to about 1.6%, which I know is much too low for some of the areas in my study site (I believe it should range from ...
1
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0answers
50 views

False calculated slope?

After the DEM creation, I wanted to create slope layer. However the result has not satisfied me. I don't think the slope map is correct. Have you ever encountered false calculated terrain map?
1
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1answer
27 views

How to find lowest elevation change using raster data and w.r.t muliple polygons

I am trying to complete a spatial analysis which yields areas (parcels of land) which are comprised of polygons (in an attribute table) that correspond to the lowest land slope regions or smallest ...
0
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0answers
22 views

Min and Max width of 3D Polygon or Multipatch feature

I am trying to carry out some analysis on a ski hill and need help with getting the right tools. I have created a TIN from lidar data and draped an ortho over the TIN in Arcscene. I have also created ...
3
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2answers
155 views

Fixed distance between two contours - Qgis 2.14.1

There is a possibility, when you select a contour line and give a fixed length of line, this line connects automatically to the next contour lines? I have two other questions on this subject but I do ...
2
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0answers
117 views

Connect two contour lines with calculated line length

Is it possible to make a plugin for QGIS like PEGGER for arcview 3.2? Problem is, how to make path over contour lines with a gradient in percent? Formula is: K= e*100/G*M ; K=10*100/0.08*10000=1.25m ...
1
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0answers
148 views

3D Polyline by Slope on Surface

I wish to project (continue/extend/whatever) a polyline upslope following a specified gradient along a DEM surface. Is there any way of doing this?
3
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2answers
110 views

How to calculate the relative share of an area of a circle that has a slope >15% in Germany

I need to calculate the share of buildable land for the 15 major german cities within a 50 kilometer radius of the city center. Part 1 of the definition buildable is that the area must have a slope &...
0
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0answers
42 views

Actual slope between two points from raster slope value

We have our own raster map and I have raster pixel slope value on map which is calculated using formula as shown in the link below Pixel Slope Calculation, which is used to show different color as per ...
4
votes
2answers
197 views

Faster way to calculate slope between two points on DEM using ArcGIS for Desktop?

I'm a forester, and I do lots of work with LiDAR derived DEM's. I'm looking for a quick-and-easy tool to calculate the slope between two points. The application for this would be drawing a proposed ...
6
votes
2answers
2k views

Calculating average slope along line using ArcGIS Desktop?

I have a slope layer and I want to calculate the average slope along a line. This line isn't necessarily straight (e.g its a route, I would like to be able to input geographic coordinates along that ...
6
votes
1answer
228 views

Directional slope calculation

I'm trying to generate rasters of slope and curvature of an elevation DTM. The particularity is that i need to be able to specify the direction (e.g 180, 270 degrees)in this calculation. I am using ...
1
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3answers
2k views

How to create the attribute table for a raster that was produced by the Slope Tool (ArcGIS10)?

I use the Slope Tool (Spatial Analyst Tool – Surface) of ArcGIS10 by ASTER GDEM (that was exported to UTM projection). The program produce new raster (with slope value), but the resulting raster ...
2
votes
1answer
214 views

Slope tool gives wrong degree values

I am trying to create a slope map in ArcMap out of a DEM. I used the Slope Tool (Spatial Analyst), selected my DEM as input and degrees as an output result. There I got the message that "The Z units ...
1
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1answer
62 views

How to avoid unexpected values in border of slope raster in QGIS

I have a DEM like After calculating slope with QGIS, it's showing the following result So, how can I remove the unexpected value at the edge of this DEM? Which is showing almost 90 degree values....
7
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3answers
239 views

Calculate average stream slope at each location along stream

I'm trying to calculate the time of concentration for every point along a stream network. To calculate the time of concentration, I need the upstream channel length and channel slope. I've been able ...
3
votes
1answer
37 views

Creating groups containing slopes of a specific range

I have a basic knowledge of QGIS and can do everything I need to do to achieve my requirements except the following. I'm trying to graphically show areas of land that contain a set of specific slope ...
4
votes
1answer
887 views

How to compute average slope and area-weighted average slope?

I am learning GIS for use in hydrologic analysis. Related to computation of overland flow there are two types of slope that I would like to be able to obtain from GIS. The first is average slope for ...
0
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1answer
176 views

Calculating slope length using LS-tool

Does anyone know how to get LS-tool mentioned in Zhang et al 2013. https://www.researchgate.net/publication/256938578_Extension_of_a_GIS_procedure_for_calculating_the_RUSLE_equation_LS_factor I tried ...
3
votes
1answer
367 views

How to display the slopes that only facing west using ArcGIS for Desktop?

Here is what I am struggling with ... In ArcGIS for Desktop I have to Derive and symbolise areas considered susceptible to avalanche risk based on the following simple rules: areas with a slope ...
2
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3answers
4k views

Calculating slope in percentage with QGIS

I'm working with QGIS, v. 2.0.1. I have several soil types. They are (amongst others) described with slope indications. I already calculated the slope from the DTM in degrees, but as description of ...
2
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0answers
47 views

How can I statistically compare the surface slope of 2 different areas?

I could use the statistical tests like t-test and ANOVA, however I am afraid those test will easily show significant differences if I use the slope values of all cells from each area.
1
vote
1answer
36 views

How to assign a value for Slope of Different percent?

I have slope percent varying form 0 to 25 percent. Now I want to give a value for each slope percent. For example, if my slope percent is 2 % , I want to assign a value of 10. As a matter of fact, ...
1
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1answer
110 views

Slope analysis of DEM in QGIS?

I have very strange problem with the raster analysis. I have a DEM as a Geo tiff and I do a slope analysis in QGIS. I've done this many times and everything was ok but this time I received reversed ...
1
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0answers
38 views

python 2 polygon intersection

I have slope values derived from a DEM which I reclassified into NoDATA and vaules which I need. Then I made a polygon from this raster. I need to do intersection or something like that with the ...
1
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1answer
54 views

Select points situated on zero degree slope

I need to choose points from SHP file, which are positioned on raster cells with 0 degree slope. Creating a slope raster from DME is not a problem, but I don’t know how to write a script that chooses ...
2
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0answers
91 views

QGIS raster calculator - crash minidump

I'm new to QGIS and using version 2.10.1-Pisa. I have two raster layers created from ASTER DEM data. I have one for slope and want to create a binary layer where only pixels between 8 and 60 degrees ...
0
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0answers
88 views

Improve Slope Raster Precision?

Im working with ArcGIS and i have a raster layer created with just four points in XYZ, the plane that forms between these four points has a slope of 10 percent. When using the tool SLOPE (3D Analyst> ...
5
votes
2answers
2k views

Calculating slope cell-by-cell in ArcPy?

I am relatively new to the ArcGIS-Python environment and want to calculate elevation raster slope. But it says "ValueError: setting an array element with a sequence". Below code is what I have. ...
1
vote
1answer
89 views

QGIS slope percent calculation

I'm using QGIS and I'm trying to calculate slope < 20% from a file I have but when I use the raster calculation SLOPE < 20 the result is all black. What am I doing wrong? The data is already in ...
11
votes
2answers
3k views

How to calculate average slope in a grid?

This is actually a two part question: Which methods are there to calculate average slope by unit (say km²) for a given area? Are there any special requirements on the data - like additional ...
0
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1answer
132 views

Slope (Spatial Analyst) output shapefile having weird values

I'm trying to calculate the slope for a raster layer using ArcMap 10.2 and the Slope (Spatial Analyst) function. The raster I'm using is an NED 10m mosaic DEM, and the mosaic's datum is in WGS 1984. I ...
0
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0answers
28 views

Predicting Potential Areas of Eagle Nests based on Slope and Elevation using Mean +- 1 Standard Deviation?

I am trying to predict Potential Areas of Eagle Nests based on Slope and Elevation using the Mean +- 1 Standard Deviation as the potential range that eagle nests could occur. I have data about known ...
5
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1answer
8k views

Calculating Topographic Wetness Index (choosing from different algorithms)

Topographic Wetness Index can be expressed as Ln(a/tanB) based on the idea of Beven and Kirkby (1979) where a is the spesific catchment area (a=A/L, catchment area (A)divided by contour lenght(...
2
votes
1answer
132 views

How to make slope map from elevation map in Lat/Long?

I have an elevation raster map of the world, in Lat/Long. When I make a slope map, the results of the raster cells will be either 0, or values close to 90. The problem seems to be that the Slope ...
1
vote
1answer
832 views

Buffer analysis - use of surface area based on DEM

I have one problem and this is that I would like to create a buffer around point. This is simple with ArcMap using the buffer tool. But is it possible to create the buffer considering also the true ...
1
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0answers
188 views

Performing Theil-Sen regression on raster data by R software

I have seven NDVI raster layers (in ERDAS img format) of an area. Each NDVI layer is the peak growing time of that year. I want to do trend analysis of NDVI values change over the years pixel by pixel....
0
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1answer
494 views

Determine start/end points for line slope calculation [duplicate]

This is a follow up question based off of this question. I have a line feature class representing storm drains and a point feature class representing where storm drains are connected. The point ...
1
vote
1answer
168 views

Calculate slope of line based off of point layer

I have a line feature class that needs to have its slope included as a field. I have a point layer that contains points and their elevations for the start and end of the line segments. How can I ...
2
votes
1answer
119 views

Calculating slope for points with downhill slopes rendered as negatives in ArcGIS

I have a DEM and a series of points. I'd like to measure the change in slope along the series of points. Distinguishing between uphill and downhill slopes matter to me, and ArcGIS' slope function ...
2
votes
1answer
638 views

Error when slope creating using ASTER 30m DEM

I have tried to create a slope map using ASTER 30m DEM obtained from internet. But when I use it to create (using ArcGIS 10 & 3D Analyst) a slope raster, the output is only 0-89 range. My ...
1
vote
1answer
64 views

Mean watershed slope - are there better methods than taking the mean of the contained slopes?

I am wondering if there are better methods for determining the mean watershed slope, other than taking the mean of the slope values contained within the watershed? For example, could or should one ...
0
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0answers
93 views

Problem in running r.slope.aspect in GRASS

I am new to GRASS GIS, and have been trying to use the r.slope.aspect function to find out the slope, dx and dy rater map from an elevation map(512*512)[1]. But I am getting the following output: ||...