On 26/02/15 00:15, image93 wrote:
Dear all, dear Moritz,
thank you again for your last usefull messages. Regarding my driving
isochrone works. Last time (December 2014), when i executed the v.isochrones
process, an error message appeared due to running of memory.
For remind, i 'm working on windows 7 with grass 7.0. The vector network
comes from OSM data ('roads cover). This is a big road network (490 lines
objects!!) with of course the usefull field for speed profile. My area of
interest is componed by the two french admnistrative regions (Ile de France
and Picardie).
I imagine you are lacking a few zeroes here. 490 lines is not a big
network ;-)
----------------------------------------------------------------------------
(Wed Feb 25 22:46:55 2015)
v.isochrones --overwrite map=roads_merge_idf_picardie_L93@dataset layer=1
speed_column=speed_prof start_points=MANUTAN_starting_points_L93@dataset
isochrones=polygons timemap=raster time_steps=15,30,45 offroad_speed=0
File "C:\Users\laurent\AppData\Roaming\GRASS7\addons/scrip
ts/v.isochrones.py", line 158, in main
null_value = resolution / (float(offroad_speed) * 1000 /
3600)
ZeroDivisionError: float division by zero
Yes, I forgot to foresee the case where the user wants an offroad speed
of 0. For now, could you just put this to a very low value > 0 ?
Actually, what you seem to want is more like what I started to implement
in the alternative method, i.e. v.net.iso + r.grow.distance in which
every pixel is just assigned to the travel time of the closest network
segment, within a user-defined distance threshold to the network (thus
potentially allowing empty areas not covered by isochrones).
I'm realy sorry to disturb you. But isochrony maps is really important my my
project.
I'll try to find some time soon to update the module with the second method.
Moritz
_______________________________________________
grass-user mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/grass-user
