Please, keep the conversation on the mailing list. On Mon, Oct 24, 2016 at 12:31 PM, Phil Burgdorf <[email protected]> wrote: > I use Grass together with QGIS. > So i donÄt know how to give you the command. I'll send you the r. info for > may input data and wrote down what I#ve done, I hope that'll give yo the > information you need. > > First i calculated the speed km/h with this formula (6e ^-3,5Islope + 0,05) > (layername:Test_Neo_Geschw) > r. info for that: > > Map: tmp1477325189748 Date: Mon Oct 24 18:06:30 2016 | > | Mapset: PERMANENT Login of Creator: Phil | > | Location: temp_location | > | DataBase: C:\Users\Phil\AppData\Local\Temp\processing99ff3938206843eb8f58e > | > | Title: ( tmp1477325189748 ) | > | Timestamp: none | > |----------------------------------------------------------------------------| > | | > | Type of Map: raster Number of Categories: 0 | > | Data Type: FCELL | > | Rows: 7832 | > | Columns: 9000 | > | Total Cells: 70488000 > | Projection: unnamed > | N: 5598800 S: 5403000 Res: 25 > | E: 4585500 W: 4360500 Res: 25 > | Range of data: min = 0.05126764 max = 0.1423827 > > After that the cost with c = 60 /v (layer name: Test_Neo_Kosten) > > r. info for that: > Map: tmp14773254289710 Date: Mon Oct 24 18:10:29 2016 | > | Mapset: PERMANENT Login of Creator: Phil | > | Location: temp_location | > | DataBase: C:\Users\Phil\AppData\Local\Temp\processing99ff3938206843eb8f58e > | > | Title: ( tmp14773254289710 ) | > | Timestamp: none | > |----------------------------------------------------------------------------| > | | > | Type of Map: raster Number of Categories: 0 | > | Data Type: FCELL | > | Rows: 7832 | > | Columns: 9000 | > | Total Cells: 70488000 > | Projection: unnamed > | N: 5598800 S: 5403000 Res: 25 > | E: 4585500 W: 4360500 Res: 25 > | Range of data: min = 421.3996 max = 1170.329 > > In r. walk I used the slope of my test region (layername: Test_Neo_Slope) as > elevation raster and the layer " Test_Neo_Kosten" as input raster for the
why do you use slope as elevation raster? It should be elevation, slope is computed internally. Also, I don't really understand how you define the cost. You should define friction as additional time to cross a cell depending on landcover for example. I suggest looking at r.walk manual, also look at: http://www.bioone.org/doi/full/10.1659/MRD-JOURNAL-D-13-00041.1 where r.walk is used. > friction cost. my starting ponit is a simple shape-point in this region. The > first result is fine. The algorithm creates a map in my test region. I > have'nt changed all the other values. As i told you the algorithm fails when > I change the Max. cost. > > > r.info for r.walk: > | Map: tmp14773265793514 Date: Mon Oct 24 18:29:43 2016 | > | Mapset: PERMANENT Login of Creator: Phil | > | Location: temp_location | > | DataBase: C:\Users\Phil\AppData\Local\Temp\processing99ff3938206843eb8f58e > | > | Title: ( tmp14773265793514 ) | > | Timestamp: none | > |----------------------------------------------------------------------------| > | | > | Type of Map: raster Number of Categories: 0 | > | Data Type: DCELL | > | Rows: 7832 | > | Columns: 9000 | > | Total Cells: 70488000 | > | Projection: unnamed | > | N: 5598800 S: 5403000 Res: 25 | > | E: 4585500 W: 4360500 Res: 25 | > | Range of data: min = 0 max = 775143.701578344 | > > I hope these informations are more helpfull. > > Gesendet: Montag, 24. Oktober 2016 um 17:46 Uhr > Von: "Anna Petrášová" <[email protected]> > An: "Phil Burgdorf" <[email protected]> > Betreff: Re: Re: Re: [GRASS-user] r. walk and sites which can be reached in > a certain time > On Mon, Oct 24, 2016 at 11:41 AM, Phil Burgdorf <[email protected]> wrote: >> Thank you for the formula. I replaced "time to walk" by my layer named >> "acumulated_cost". >> So it's now: "accumulated_cost_limited = if(acumulated_cost < 3600, >> acumulated_cost,null())" Is that right? >> After running the caclculator I didn't get a new raster map althogh it >> says >> "algorithm finished" > > > You have to provide more information. What does r.info acumulated_cost > show? What's the r.walk command you used and what are the input data? > Did you set the computational region to match your input data (see > g.region)? > >> >> Gesendet: Montag, 24. Oktober 2016 um 16:34 Uhr >> Von: "Anna Petrášová" <[email protected]> >> An: "Phil Burgdorf" <[email protected]>, "GRASS user list" >> <[email protected]> >> Betreff: Re: Re: [GRASS-user] r. walk and sites which can be reached in a >> certain time >> On Mon, Oct 24, 2016 at 10:22 AM, Phil Burgdorf <[email protected]> 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" <[email protected]> >>> An: "Phil Burgdorf" <[email protected]> >>> Cc: "GRASS user list" <[email protected]> >>> 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 <[email protected]> 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 >>>> >>>> >>>> _______________________________________________ >>>> grass-user mailing list >>>> [email protected] >>>> http://lists.osgeo.org/mailman/listinfo/grass-user >>> >> > _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
