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<div>Thanks for your help!</div>
<div>At least i've got the solution. I was confused about the cost because a colleague of mine used it in another algorithm.</div>
<div>Now th max. Cost work as well.</div>
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<div style="margin:0 0 10px 0;"><b>Gesendet:</b> Dienstag, 25. Oktober 2016 um 03:07 Uhr<br/>
<b>Von:</b> "Anna Petrášová" <kratochanna@gmail.com><br/>
<b>An:</b> "Phil Burgdorf" <P_Burgdorf@web.de>, "GRASS user list" <grass-user@lists.osgeo.org><br/>
<b>Betreff:</b> Re: Re: Re: Re: [GRASS-user] r. walk and sites which can be reached in a certain time</div>
<div name="quoted-content">Please, keep the conversation on the mailing list.<br/>
<br/>
On Mon, Oct 24, 2016 at 12:31 PM, Phil Burgdorf <P_Burgdorf@web.de> wrote:<br/>
> I use Grass together with QGIS.<br/>
> So i donÄt know how to give you the command. I'll send you the r. info for<br/>
> may input data and wrote down what I#ve done, I hope that'll give yo the<br/>
> information you need.<br/>
><br/>
> First i calculated the speed km/h with this formula (6e ^-3,5Islope + 0,05)<br/>
> (layername:Test_Neo_Geschw)<br/>
> r. info for that:<br/>
><br/>
> Map: tmp1477325189748 Date: Mon Oct 24 18:06:30 2016 |<br/>
> | Mapset: PERMANENT Login of Creator: Phil |<br/>
> | Location: temp_location |<br/>
> | DataBase: C:\Users\Phil\AppData\Local\Temp\processing99ff3938206843eb8f58e<br/>
> |<br/>
> | Title: ( tmp1477325189748 ) |<br/>
> | Timestamp: none |<br/>
> |----------------------------------------------------------------------------|<br/>
> | |<br/>
> | Type of Map: raster Number of Categories: 0 |<br/>
> | Data Type: FCELL |<br/>
> | Rows: 7832 |<br/>
> | Columns: 9000 |<br/>
> | Total Cells: 70488000<br/>
> | Projection: unnamed<br/>
> | N: 5598800 S: 5403000 Res: 25<br/>
> | E: 4585500 W: 4360500 Res: 25<br/>
> | Range of data: min = 0.05126764 max = 0.1423827<br/>
><br/>
> After that the cost with c = 60 /v (layer name: Test_Neo_Kosten)<br/>
><br/>
> r. info for that:<br/>
> Map: tmp14773254289710 Date: Mon Oct 24 18:10:29 2016 |<br/>
> | Mapset: PERMANENT Login of Creator: Phil |<br/>
> | Location: temp_location |<br/>
> | DataBase: C:\Users\Phil\AppData\Local\Temp\processing99ff3938206843eb8f58e<br/>
> |<br/>
> | Title: ( tmp14773254289710 ) |<br/>
> | Timestamp: none |<br/>
> |----------------------------------------------------------------------------|<br/>
> | |<br/>
> | Type of Map: raster Number of Categories: 0 |<br/>
> | Data Type: FCELL |<br/>
> | Rows: 7832 |<br/>
> | Columns: 9000 |<br/>
> | Total Cells: 70488000<br/>
> | Projection: unnamed<br/>
> | N: 5598800 S: 5403000 Res: 25<br/>
> | E: 4585500 W: 4360500 Res: 25<br/>
> | Range of data: min = 421.3996 max = 1170.329<br/>
><br/>
> In r. walk I used the slope of my test region (layername: Test_Neo_Slope) as<br/>
> elevation raster and the layer " Test_Neo_Kosten" as input raster for the<br/>
<br/>
why do you use slope as elevation raster? It should be elevation,<br/>
slope is computed internally. Also, I don't really understand how you<br/>
define the cost. You should define friction as additional time to<br/>
cross a cell depending on landcover for example. I suggest looking at<br/>
r.walk manual, also look at:<br/>
<a href="http://www.bioone.org/doi/full/10.1659/MRD-JOURNAL-D-13-00041.1" target="_blank">http://www.bioone.org/doi/full/10.1659/MRD-JOURNAL-D-13-00041.1 </a><br/>
where r.walk is used.<br/>
<br/>
<br/>
> friction cost. my starting ponit is a simple shape-point in this region. The<br/>
> first result is fine. The algorithm creates a map in my test region. I<br/>
> have'nt changed all the other values. As i told you the algorithm fails when<br/>
> I change the Max. cost.<br/>
><br/>
><br/>
> r.info for r.walk:<br/>
> | Map: tmp14773265793514 Date: Mon Oct 24 18:29:43 2016 |<br/>
> | Mapset: PERMANENT Login of Creator: Phil |<br/>
> | Location: temp_location |<br/>
> | DataBase: C:\Users\Phil\AppData\Local\Temp\processing99ff3938206843eb8f58e<br/>
> |<br/>
> | Title: ( tmp14773265793514 ) |<br/>
> | Timestamp: none |<br/>
> |----------------------------------------------------------------------------|<br/>
> | |<br/>
> | Type of Map: raster Number of Categories: 0 |<br/>
> | Data Type: DCELL |<br/>
> | Rows: 7832 |<br/>
> | Columns: 9000 |<br/>
> | Total Cells: 70488000 |<br/>
> | Projection: unnamed |<br/>
> | N: 5598800 S: 5403000 Res: 25 |<br/>
> | E: 4585500 W: 4360500 Res: 25 |<br/>
> | Range of data: min = 0 max = 775143.701578344 |<br/>
><br/>
> I hope these informations are more helpfull.<br/>
><br/>
> Gesendet: Montag, 24. Oktober 2016 um 17:46 Uhr<br/>
> Von: "Anna Petrášová" <kratochanna@gmail.com><br/>
> An: "Phil Burgdorf" <P_Burgdorf@web.de><br/>
> Betreff: Re: Re: Re: [GRASS-user] r. walk and sites which can be reached in<br/>
> a certain time<br/>
> On Mon, Oct 24, 2016 at 11:41 AM, Phil Burgdorf <P_Burgdorf@web.de> wrote:<br/>
>> Thank you for the formula. I replaced "time to walk" by my layer named<br/>
>> "acumulated_cost".<br/>
>> So it's now: "accumulated_cost_limited = if(acumulated_cost < 3600,<br/>
>> acumulated_cost,null())" Is that right?<br/>
>> After running the caclculator I didn't get a new raster map althogh it<br/>
>> says<br/>
>> "algorithm finished"<br/>
><br/>
><br/>
> You have to provide more information. What does r.info acumulated_cost<br/>
> show? What's the r.walk command you used and what are the input data?<br/>
> Did you set the computational region to match your input data (see<br/>
> g.region)?<br/>
><br/>
>><br/>
>> Gesendet: Montag, 24. Oktober 2016 um 16:34 Uhr<br/>
>> Von: "Anna Petrášová" <kratochanna@gmail.com><br/>
>> An: "Phil Burgdorf" <P_Burgdorf@web.de>, "GRASS user list"<br/>
>> <grass-user@lists.osgeo.org><br/>
>> Betreff: Re: Re: [GRASS-user] r. walk and sites which can be reached in a<br/>
>> certain time<br/>
>> On Mon, Oct 24, 2016 at 10:22 AM, Phil Burgdorf <P_Burgdorf@web.de> wrote:<br/>
>>> Hi Anna,<br/>
>>> thanks for your answer. I've tried to use 3600 as max. Cost but the<br/>
>>> algorithm failed.<br/>
>><br/>
>> That's weird.<br/>
>><br/>
>>> The values for min and max for the cummulative cost are "nan". But I<br/>
>>> don't<br/>
>>> know why!<br/>
>>> How can I do this in r. mapcalc. I haven't used it before<br/>
>><br/>
>><br/>
>> r.mapcalc "time_to_walk_limited = if(time_to_walk < 3600, time_to_walk,<br/>
>> null())"<br/>
>><br/>
>> Please keep the discussion on the mailing list.<br/>
>><br/>
>><br/>
>>> Phil<br/>
>>><br/>
>>> Gesendet: Montag, 24. Oktober 2016 um 16:02 Uhr<br/>
>>> Von: "Anna Petrášová" <kratochanna@gmail.com><br/>
>>> An: "Phil Burgdorf" <P_Burgdorf@web.de><br/>
>>> Cc: "GRASS user list" <grass-user@lists.osgeo.org><br/>
>>> Betreff: Re: [GRASS-user] r. walk and sites which can be reached in a<br/>
>>> certain time<br/>
>>> On Mon, Oct 24, 2016 at 7:52 AM, Phil Burgdorf <P_Burgdorf@web.de> wrote:<br/>
>>>> Hello there,<br/>
>>>> my name is Phil and I'm a PhD Student in Archaeology and I'm analiesing<br/>
>>>> a<br/>
>>>> small area in bavaria. I'm trying to locate archaeological sites round<br/>
>>>> different strating points. Therefor I created a cost map using r. walk.<br/>
>>>> The<br/>
>>>> result is fine but how can I adapted my values. Actualy I'm interrested<br/>
>>>> in<br/>
>>>> sites which can be reached in, let's say, one hour. I've tried to change<br/>
>>>> the values for max costs but I didn't get any results. Do i have to use<br/>
>>>> a<br/>
>>>> nother algorithm? here must be an easy way to define the max cost for<br/>
>>>> that<br/>
>>>> analysis.<br/>
>>>><br/>
>>>> I couldn''t find any help in the mailing list's archive and I#m totally<br/>
>>>> lost. Can you help me?<br/>
>>><br/>
>>> max_cost will do the trick, don't forget that the time is in seconds.<br/>
>>> You can also use raster algebra (r.mapcalc) to extract the area within<br/>
>>> certain time.<br/>
>>><br/>
>>> Anna<br/>
>>><br/>
>>>><br/>
>>>> Cheers<br/>
>>>> Phil<br/>
>>>><br/>
>>>><br/>
>>>> _______________________________________________<br/>
>>>> grass-user mailing list<br/>
>>>> grass-user@lists.osgeo.org<br/>
>>>> <a href="http://lists.osgeo.org/mailman/listinfo/grass-user" target="_blank">http://lists.osgeo.org/mailman/listinfo/grass-user</a><br/>
>>><br/>
>><br/>
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