Cost-distance function

Discussion created by ulises.hm on Aug 26, 2012
Latest reply on Aug 30, 2012 by xander_bakker
Hello GIS community,

I have developed an accessibility surface to health facilities using the cost-distance function in ArcMap 10 (ArcInfo).
I created 1) a target raster map containing the locations of health facilities, and 2) a friction-surface raster where each pixel contains the estimated time (in seconds) required to cross that pixel (based on different travel speeds according to different land classes that include roads). The resolution of my rasters is 30m by 30m.??? Using the cost-distance function, the friction surface and raster of target locations were then used to compute the travel time from each pixel in the study area to the nearest target location.

My problem is that I am getting really weird values in the outcome raster. The raster displays nicely and accurate in terms of showing accessibility. Higher accessibility can be seen through road networks evident in the raster. However, the values range from 0 - 32, 443, 300 as it can be seen on my attachment.

Can anyone shed some light on the values?

Thank you in advance