2

I'm working on site accessibility. Having various locations, I can identify the LCP going from one to any other. So, by default, LCP calculation is giving me the first most least-cost path only. I can use various programs to get a few different options, but they generally point to the same general direction.

I wonder if anyone knows a way to get other paths which, despite being more costly, could be used as an alternative. As I see it, it could imply using a simple XY chart (X being each alternative and Y the cost) and splitting it in natural breaks or quartile, or whatever method. I suppose it would need to calculate a lot more.

Maybe it already exists in some road GPS applications (for an example, pointing out various roads to avoid jams or something) ? If so, how could it be used with elevation rasters?

  • I tried calculating LCP between a few point based on two slope maps with Z Scale values (namely 1.0 - default - and 10.0). The paths I get are slightly different, but not really alternative. – gvanhavre Oct 11 '15 at 19:29
2

Well, as all LCPA-tools search for the LCP in more or less the same way their results don´t differ a lot. LCPA tools are not looking for random paths between point but for the the path with least costs based on the input cost layer.

So in order to recieve different paths between locations it could be necessary to define impact models and "assign a level of importance weight to each cost factor within its’ model." Have a look at this tutorial using SAGAGIS: http://mirror.ufs.ac.za/sagagis/SAGA%20-%20Documentation/Tutorials/Least_Cost_Path_Analysis_Tutorial/LCPAtutorial.pdf

If you´re looking for different results you also have to insert different inputs.

Sorry if I´m not able to give you a more suitable answer to your question but I can´t really get your point regarding what you describe with XY chart...

  • Thanks for your answer, and sorry to answer so late. I've been following your idea to insert different inputs: I created a buffer around the initial location, and extracted a number of nodes, to which I directed the LCP analysis. Depending the size of the buffer, some alternative paths began to emerge, which could then be linked to the main point. – gvanhavre Apr 12 '16 at 18:56

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.