I am trying to build isochrones of 5, 10, and 15 minutes walking time from service area points using ArcMAP 10.4.1. I used Digimap's Integrated Transport Network merged with Digimap's Urban Path as network source data. The first result of running the analysis, i found that some points do not seems to generate correct isochrone, or even no isochrone at all, as seen below:
I also have another different points dataset but when I tried network analysis to those data with the exact same first method (using ITN and Urban Path merged as network data) I did not experience any problem.
Does anyone know why and how to correct this?