topic Re: Least cost path issues in Data Management Questions

Least cost path issues

SeanParks — Wed, 16 Jun 2010 16:29:22 GMT

Hi,

I'm attempting to create a least cost path for two points, a source point and a destination point. I am using the "costdistance" and "costpath" functions in Spatial Analyst.

Everything appears to run fine, but when I look at the results, something seems amiss. The main problem is that the actual "path" does not link the source and destination point (please see 'test_path.jpg'). As you will see, the actual path starts two cells from the source point and ends one cell before the destination point.

The issue with the starting point being two cells away from the actual start of the path may have something to do with the "cost" grid created using the "costdistance" function. If you look at the second jpeg ("test_costdist.jpg") you will see that the cost grid shows that the zero cost pixel, which I would expect to align with the source point, is actually shifted by one pixel. This seems quite odd.

Anyone please have any thoughts/comments on this issue?

Thanks,
Sean Parks

SOLUTION: Least cost path issues

SeanParks — Thu, 17 Jun 2010 22:20:13 GMT

I solved the problem:

Don't use point features as your source or destination locations within the LCP framework.

Once I converted source and destination points to grids, the LCP worked as expected.

This may be a bug of some sort ... pretty weak.

Cheers,
Sean

Re: Least cost path issues

Anonymous User — Fri, 18 Jun 2010 07:33:51 GMT

Original User: Adversus

which version are you on? I've done LCP with 9.3.1 using points as start and stop, and cost surface with 5 meter resolution. I don't recall getting this error (but I will check next week if it actually didnt happen).

Re: Least cost path issues

PabloVega — Thu, 19 Apr 2012 09:46:12 GMT

I'm finding this problem as well, and I'm using ArcGIS10

I was trying to convert the points to raster using Point To Raster as a workaround, but it doesn't seem to be a suitable solution. I have only one point per shapefile (one FROM and one TO), and when I try to convert each of them ot a raster I obtained empty datasets that, for some reason, cannot calculate histograms (without any error message). Am I using the right tool (Point to Raster)? Is there any other way to workaround this problem?

For some reason, these appartently empty rasters are able to generate a Distance and Backlink rasters, but fail on calculating Cost Path (010414 : Error in creating a Raster from a geodataset.)

thank you and best regards for any help you may be able to provide.