The slope of a line or surface is a numerical measure of steepness or incline.

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9
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3answers
1k views

Calculating mean slope: Harmonic or Arithmetic Mean?

I have to calculate the average upslope percent slope for a large dataset, the basic method is detailed here. However, I've begun to wonder if harmonic mean might be more appropriate than the ...
5
votes
2answers
96 views

How to automate creation of toe of slope from DEM?

I was looking for an automated process to "identify" the toe of a slope from a DEM and ran across this ESRI thread and technique: I am at Step 7 but have no idea how this is accomplished. I get it is ...
5
votes
3answers
552 views

How to calculate changes in slope angle between cells/areas?

I am doing an estimation of erosion with ArcGIS. I use the UniversalSoilLossEquation (USLE) for this. Now, i want to calculate the L-factor of this equation. I need the FlowLength for this. My ...
5
votes
1answer
2k 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 ...
5
votes
2answers
54 views

Compare slopes between adjoining line segments

Using a DEM, I assigned slope values to individual segments in a street network feature class. In some areas the slope values seem suspect, such as where a highway overpasses a local road. Is there a ...
5
votes
2answers
163 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 ...
4
votes
1answer
101 views

How do I use a DHM in tiff format for distance and slope measurements?

I am a student and I have to work out a project about soil loss on a plot. I need basic measurements of this plot such as length, width, area and slope for my erosion calculations. I have got my ...
4
votes
1answer
39 views

How do I consider entity alignment against slope direction?

I am a newbie to QGIS and don't know if the following is possible so would be grateful of any thoughts. I have a hill, most of which is given over to rectangular pasture fields. I hypothesize that ...
3
votes
2answers
139 views

Matching vector network to slope raster dataset in ArcGIS for Desktop Advanced 10.1

I am trying to calculate the average slope of a rivers network. Each part of the network is broken up into individually numbered segments. I have a high resolution slope raster and thought I could ...
3
votes
1answer
431 views

How is slope of a surface in an arbitrary direction produced?

I am currently developing a program that requires that I calculate the slope for each cell in a DEM. However when I try to understand the algorithm to be used I get stuck trying to understand exactly ...
3
votes
1answer
254 views

Calculating Mean Upslope slope, curvature, etc

I'm trying to generate rasters whose values summarize the mean value of a given parameter (slope, curvature, etc.) of the upslope terrain. I feel like this should be doable using only a flow ...
3
votes
1answer
84 views

What function should I use to assess the degree of elevational change (rocky cliffs etc.) of a DEM?

I have a DEM of my research area and I want to assess how the topography/elevation changes. I am specifically looking to see what areas may be good suitable bat-roosting habitat so I am trying to ...
3
votes
1answer
34 views

ArcPy Slope Script - Trouble Saving

I have an ArcPy script that applies the slope function to raster files in ArcGIS. I tried running the script with two raster files in the table of contents, and the script runs, but only saves one ...
3
votes
1answer
149 views

Compute global DEM topographic indices and compromise projections

I would like to compute global topographic indices based on SRTM elevation data. These indices are computed along river/channel networks extracted from a DEM and are a functions of both local slope ...
3
votes
1answer
111 views

Wrong direction in r.watershed slope length calculation?

Or have I completely misunderstood something now? As a programmer I took it for granted that the row number would change if I traversed the map up and down in the program along the North-South axis ...
2
votes
4answers
414 views

Error When Trying to Run Slope Analysis Script

I have written a script which is supposed to loop through all the rasters in a folder and perform a slope analysis on each raster and save the results in another folder. I keep getting the following ...
2
votes
3answers
414 views

Creating a Slope Map Using Contours

I am trying to create a slope map. I have many contour elevation files. I tried to use the slope tool in Arctoolbox, but it calls for raster files and I'm working with vector data. Any help with this ...
2
votes
2answers
218 views

Calculate Slope Between Pixels Through Time: A Time Series Trend Analysis

I have a 9 year weekly time series (~500 raster grids of equal cell size and extent). I'm interested in obtaining the regression line slope between pixels (Imagine stacking all 500 grids on top of ...
2
votes
2answers
86 views

Arcpy Slope Analysis Script

I'm trying to run slope analysis in ArcGIS. I have written an ArcPy script that converted feature layers to raster files. Now I have a list of rasters (each with a unique name) in the table of ...
2
votes
1answer
217 views

Toblers's Hiking Equation and Slope Dilemma

I'm trying to use Toblers's Hiking equation to determine economical backgrounds of some hillforts. The equation is anisotropic which means that the speed of movement that it calculates differs whether ...
2
votes
2answers
357 views

Calculate Slope of Street Segments

Using a DEM, I need to assign slope to individual segments in a street centerline feature class. It will be used to account for increased travel time for steep slopes in a network analysis. I am ...
2
votes
1answer
73 views

How to disassociate roughness from slope

How to measure topographic roughness irrespective of slope in ArcGIS? I have used many methods to generate roughness layers, including TRI, VRM (which is supposed to be less correlated with slope), ...
2
votes
1answer
49 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 ...
2
votes
1answer
219 views

qgis2 slope analysis from NED data gives crazy histogram

I'm attempting a simple slope analysis in QGIS2 using the plugin at Raster -> Terrain Analysis -> Slope. The slope output layer has a very strange histogram, basically spikes at 0 and at 89.9098 with ...
2
votes
1answer
585 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
3k 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 ...
2
votes
1answer
262 views

Hydrology tool dataset in ArcGIS 10.1 for calculating slope?

I am quite new to the hydrology toolset in ArcGIS and thought it may be useful for extracting slope data from a raster; I was wondering if anyone had experience trying to extract slope data upslope ...
2
votes
1answer
138 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? ...
2
votes
1answer
118 views

Slope tool error when running from arcObject add-in tool

My problem is related with Global DEM to Slope calculation. The slope tool works when raster is projected or the map is projected where the raster is added. And also, if the raster and map both are ...
2
votes
1answer
42 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 ...
2
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0answers
23 views

How to calculate the slope with isolines/raster?

I'm trying to calculate the slope (in %) in ArcGis 9.3, but don't remember how it works. I already did it some time ago, but this time it doesn't work... I used a shapefile with Isolines (see ...
2
votes
0answers
22 views

How to re-slope a given DEM to pre-determined slope in ArcGIS?

I have a set of topographic contours of a mine and like to re-slope those areas alongside the river to a pre-determined slope, say 22˚; and 27˚ for water pond wall. The existing slopes along the river ...
2
votes
0answers
76 views

In ArcMap, when using Add Surface Information, why are all avg_slope values positive?

I've got a polyline shapefile and a LIDAR elevation dataset. I've successfully used Add Surface Information (from 3D Analyst) to calculate the average slope (avg_slope) of each line segment. The ...
2
votes
1answer
333 views

GTOPO30 Slope analysis in ArcGIS 10.1 [duplicate]

Using surface - slope analysis tool box. All values for the slope calculation are in between 80 and 89. There are no values below 80. What am I doing wrong?
1
vote
2answers
141 views

Calculate area inside polygons based on slope

I have some DEMs and have computed the slope in degrees for each one. I have also classified the slope raster into the following 5 classes: 0-3, 3-15, 15-35, 35-50, >50. What I want to do is to ...
1
vote
3answers
490 views

Calculating slope in percentage

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 de description of ...
1
vote
1answer
312 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
vote
1answer
107 views

How to calculate the river slope for a lot of rivers automatically in ArcMap?

I'm working with ArcMap 10.2 and I'm pretty new in this area.. What I want to do is compute the river slope for a lot of rivers from a DTM...I know that there is a way to do it manually passing by ...
1
vote
1answer
67 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 ...
1
vote
1answer
124 views

QGIS Slope Classification Issues

I am very new to QGIS for the primary purpose of creating a slopes layer so we know where slopes are above 15% or 20% or whatever we finally decide. I have used our DEM to create a slope geotif and ...
1
vote
1answer
175 views

How can i calculate average slope and length of slope of a multiple field farm in Arcmap 10?

I always calculate slope on farms i review with 2' contour lines. Some fields are difficult since i need the average slope, but the field is rolling hills. I usally take several slopes and take the ...
1
vote
1answer
336 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
226 views

How to calculate relative height of point on slope relative to nearest creek and ridge?

I'm attempting to calculate the relative height (values between 0 and 1 preferably) of waypoints on a slope along the path of least resistance. Ideally, points in creeks would have values of 0 and ...
1
vote
1answer
17 views

Seeking finer points of slope statistics within set of polygons?

Do not mark as duplicate please.. I have a few questions related to finding slope statistics (min, max, mean, standard deviation) of slopes (1-meter LiDAR DEM derived) within a set of polygons ...
1
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0answers
17 views

gdaldem slope attribute passing

How to pass slope attribute to the command "gdaldem slope manj.tif outpiu.tif -p use percent 45 -s 111120/370400" It's giving error like FAILURE: Too many command options. give any ...
1
vote
1answer
17 views

GRASS: v.drape, v.split and v.to.db on spearfish sample data

I am new to GRASS and started training on the spearfish sample data set in GRASS 6.4.3. I selected a bicycle tour and transformed it into a polyline. My next goal is to read out the slope and ...
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0answers
64 views

Split 3D line feature at vertices based on slope change

I've already asked a question about this subject, but now I think I'm almost getting to the point. I have to split roads in ramps to calculate LS factor (RUSLE - soil erosion) These are the steps ...
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vote
0answers
192 views

validating the calculation of slope from DEM

my purpose is to calculate and validate slope in percentage of southern california using DEM and landsat data. step 1)i used a DEM file and changed with the float type file to integer type step 2) i ...
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vote
0answers
141 views

cut/fill calculation tool to investigate if there is enough material to achieve a 30 degree slope

This is a cut/fill problem. We have pits that have been dug in the ground, usually rectangular. They have a bund wall around them. They are being rehabilitated by pushing the bund back into the pit. ...
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vote
0answers
427 views

Calculating Accurate % Grade from GPS Coordinates

I am trying to calculate % Grade from GPS points. I am using the basic equation of (Rise/Run)×100 The problem is I am getting spikes in my GPS data (example 1 meter rise for 3 meter run), I am ...