[GRASS-user] r. walk and sites which can be reached in a certain time

[Anna Petrášová]

On Mon, Oct 24, 2016 at 10:22 AM, Phil Burgdorf <P_Burgdorf at web.de> wrote:
> Hi Anna,
> thanks for your answer. I've tried to use 3600 as max. Cost but the
> algorithm failed.

That's weird.

> The values for min and max for the cummulative cost are "nan". But I don't
> know why!
> How can I do this in r. mapcalc. I haven't used it before


r.mapcalc "time_to_walk_limited = if(time_to_walk < 3600, time_to_walk, null())"

Please keep the discussion on the mailing list.


> Phil
>
> Gesendet: Montag, 24. Oktober 2016 um 16:02 Uhr
> Von: "Anna Petrášová" <kratochanna at gmail.com>
> An: "Phil Burgdorf" <P_Burgdorf at web.de>
> Cc: "GRASS user list" <grass-user at lists.osgeo.org>
> Betreff: Re: [GRASS-user] r. walk and sites which can be reached in a
> certain time
> On Mon, Oct 24, 2016 at 7:52 AM, Phil Burgdorf <P_Burgdorf at web.de> wrote:
>> Hello there,
>> my name is Phil and I'm a PhD Student in Archaeology and I'm analiesing a
>> small area in bavaria. I'm trying to locate archaeological sites round
>> different strating points. Therefor I created a cost map using r. walk.
>> The
>> result is fine but how can I adapted my values. Actualy I'm interrested in
>> sites which can be reached in, let's say, one hour. I've tried to change
>> the values for max costs but I didn't get any results. Do i have to use a
>> nother algorithm? here must be an easy way to define the max cost for that
>> analysis.
>>
>> I couldn''t find any help in the mailing list's archive and I#m totally
>> lost. Can you help me?
>
> max_cost will do the trick, don't forget that the time is in seconds.
> You can also use raster algebra (r.mapcalc) to extract the area within
> certain time.
>
> Anna
>
>>
>> Cheers
>> Phil
>>
>>
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>