7
votes
Creating Buffer Polygon following Elevations using ArcGIS Desktop?
Workaround for what you describe in absence of spatial analyst:
arcpy.Buffer_analysis("target","../buffer.shp", "100 Meters")
arcpy.FeatureVerticesToPoints_management("buffer","../points.shp","ALL")
...
- 23.2k
7
votes
Accepted
Transition Function Inputs
The answer to your question is indeed not obvious from the documentation. In figuring out what the transition function actually refers to, it helps to look into the source code of that function. In ...
- 298
6
votes
How to create an OD road distance matrix in QGIS?
UPDATE - QGIS3:
Since this seems to be an important topic, I would like to share my answer on a similar question.
If you are using the current version of QGIS (3), you can use the plugin QNEAT3. It ...
- 2,385
6
votes
Accepted
How can I estimate a Least Cost Path in Google Earth Engine?
Because you are using the ee.Image.and() method in your cost calculation, the resulting cost variable is binary. That is why the results seem non-sensical.
The units of the output of ee.Image....
- 5,411
5
votes
Accepted
Road design using Least cost path by longitudinal slope in ArcGIS Desktop?
Connecting 2 points on contours by straight line is not going to work, as seen on your second picture line crosses same contour twice. I also very much doubt that any out of the box tools can help you....
- 23.2k
5
votes
Least Cost Path Analysis in QGIS?
It seems you're mostly confused about how to define cost. I highly recommend this post by Amanda Briney on GIS Lounge, especially the Requirements for Least Cost Path Analysis section.
Cost can be ...
- 25k
4
votes
Accepted
Least cost path barrier (R) (gdistance)
There are several options to create this type of barrier by using the transitionFuntion argument in the transition function strategically. This should cover 99% of the cases. Set the conductance value ...
4
votes
Accepted
Tobler's hiking function: resulting walking speed in KmH or m/s?
The formulae in wikipedia and the R doc are identical, lets see what they say walking speed is on flat ground:
> tobr = function(m){6 * exp(-3.5*abs(m+0.05))}
> tobr(0)
[1] 5.036742
About 5 ...
- 65.5k
4
votes
Accepted
Least cost path: what does least cost value represent, based on slope raster layer
The plugin uses the Djikstra algorithm.
For orthogonal directions (up, down, left, right), the cost to move between two pixels is:
(pixel 1 + pixel 2) / 2
For diagonal pixels, it's:
sqrt(2) * (pixel ...
- 67.7k
3
votes
Mosaic to Raster Tool in ArcGIS Darkening Grayscale Raster Output
This is normal when mosaic multiple images into one mosaic image. The data did not change, what have changed is the appearance of the final mosaic image. The original data have different minimum and ...
- 41.2k
3
votes
Accepted
Open source alternative to Linkage Mapper & ArcGIS
QGIS (open source) has a new plugin called Least-Cost-Paths Network (open source, GNU GPL v3) (https://github.com/xrubio/LCPNetwork) that will take a set of origin and destination points and calculate ...
- 1,870
3
votes
Accepted
Assign different values to each zone, ArcGIS 10
If you have Spatial Analyst, you can use Reclassify tool to change the old pixel values to new values.
However, The tool may not work with decimals (I did not test it with decimals), but I know it ...
- 41.2k
3
votes
Making least-cost paths to avoid specific land-cover types using ArcGIS Desktop?
An approach, not saying it is the best, is to exclude those areas when constructing the cost distance raster by setting them to NODATA.
When you build your cost distance raster using the Cost ...
- 44.1k
3
votes
Finding least cost path to diffuse resource using ArcGIS Pro?
I used standard Cost Allocation tool with elevation being a cost surface to get this:
If they travel by foot, use method described here.
- 23.2k
3
votes
Calculate cell distance between cells
Here I have an alternative where you can set your own parameters, file names, etc, but using R (not big deal).
Here is data for tryout: https://www.dropbox.com/s/a40kk9gl1128qcl/RasterDistance.zip?dl=...
- 3,494
3
votes
Cartographic Depth-To-Water method using Cost/Path Distance
I've also been hammering away at this process a bit to map wet areas using some additional information gleaned from this paper (available open source and on researchgate):
White, B., Ogilvie, J., ...
- 41
3
votes
Accepted
Change Value of Cell in Cost Layer (Raster) by whether it touches neighbouring cell
This can be done as a raster analysis, with no need to vectorize, in two steps using the GRASS processing tools in QGIS:
Run r.neighbors with "minimum" neighbor operation and neighborhood ...
- 67.7k
2
votes
Accepted
C-based implementation of Djikstra's or Fast Marching for QGIS/Python?
There are two modules in QGIS Python included:
Scipy csgraph:
http://docs.scipy.org/doc/scipy-0.14.0/reference/generated/scipy.sparse.csgraph.dijkstra.html
NetworkX:
http://networkx.readthedocs.io/en/...
- 6,772
2
votes
How to find a least cost path through several points?
In Customize make sure that Network Analyst is turned on. Then, under Network Analyst Tools, under Analysis, open Make Route Layer. Input the set of points you would like to have your route travel ...
2
votes
Fixing ModelBuilder error? Error 010045: COSTPATH: The number of FROM cells is 0
Try making Start_123, Output Cost Distance, and Output Backlink prerequisites to Cost Path. What ModelBuilder is probably trying to do is run the Cost Path operation first, before the other bits of ...
- 677
2
votes
Automating procedure to calculate least-cost path to destination locations from multiple source locations using ArcGIS Desktop?
I recently came up against a very similar challenge and produced the model below using ArcGIS ModelBuilder.
The key part here is the "Iterate Feature Selection" element. It will output each of the ...
- 225
2
votes
Accepted
QGIS Least Cost Distance Points to Destinations via Roads
The solution is to use the GRASS algorithm v.net.allpairs.
See here for documentation.
Also see Spatial distance analysis in QGIS - not all steps are necessary for my solution, but it was most ...
- 822
2
votes
Accepted
Automated mapping of cost paths from multiple origin points
With elevation being single component of cost surface, the task is purely hydrological and can be saved by using relevant Spatial Analyst toolbox.
Fill elevation model to remove sinks
Compute flow ...
- 23.2k
2
votes
Accepted
Cost Path in ArcGIS Desktop drawing no path?
I strongly believe that Fill DEM & Flow Direction is the best to achieve your goal nevertheless I did:
arcpy.gp.CostBackLink_sa("POINTS", "DEM", "C:/JOBS/SCRATCH/blink")
arcpy.gp.CostPath_sa("...
- 23.2k
2
votes
Cannot get field value from shapefile
The problem may be that you are referencing a shapefile and not a feature class. Or that the path to the shapefile is not being found.
One thing that I usually do when running a new Python script is ...
- 664
2
votes
Accepted
Unit of costmap created by r.walk
The problem here is you used a geographic projection, so the cells are not square, so the units are not going to make sense. The only way this works is to use a UTM raster with square cells. With a ...
- 513
2
votes
Cost Distance Analysis QGIS with Vector files
You have to use PyQGIS for that, here is an example:
# define the point
pt = QgsPoint(572470.29638,191838.143182)
pt = QgsGeometry.fromPoint(pt)
# get the active polygon
layer = qgis.utils.iface....
- 1,565
2
votes
Finding Least Cost Corridor in QGIS?
What you are talking about called graph simple paths problem. Basic graph below has 2^5 = 32(!) simple paths connecting "From" and "To" nodes, because there are 5 intersections ...
- 23.2k
2
votes
Looking for land value data for anywhere in North America especially for Florida
Land value (at the parcel level) is typically available from each county's Assessor office. Most of these offices have web sites that allow you to download their parcel data (including assessed value)...
- 8,314
2
votes
Create polygon of fixed area based on cost/friction surface
I've checked and not sure anymore this is doable in model, because it needs computation of cumulative total in the table. Anyway script below solves 1st part of your question.
import arcpy,scipy
from ...
- 23.2k
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