Hi Pedro, Thank you for the reply and it helped me a lot. So here what I did. I needed to create the raster file such wind speed is 230 ft/min. So I used the following command.
r.mapcalc "new_wind_speed = 350" Then I run the fire behavior module and observed the changing of the spread. Did the same procedure for wind direction. r.mapcalc "new_wind_direction = 50" I want to know that whether what I did was correct and is it the right way to create input raster file. BR, Vidura Dantanarayana. On Mon, Sep 3, 2018 at 4:52 PM Pedro Venâncio <[email protected]> wrote: > Hi Vidura, > > Just like Moritz said, you need to start by the basics about GRASS. > > That said, it is better to create new raster layers than change the > existing ones. > > To test other wind speed and direction, moisture, etc, just create new > rasters with r.mapcalc > > https://grass.osgeo.org/grass74/manuals/r.mapcalc.html > > Start with constant rasters, using the example in the r.mapcalc manual. > > Best regards, > Pedro Venâncio > > > A seg, 3/09/2018, 06:22, Vidura Dantanarayana <[email protected]> > escreveu: > >> Hi Pedro, >> >> Thank you very much for the explanation. That helped me to get a basic >> idea of what these files do. Then what I did was to change these files. I >> changed some records in wind speed and wind direction (the files in >> demomapset/cats). But what I observed was there was no change in the shape >> of spread even after the alterations. Is there anyone who willing to help >> me in crating custom files if I provide the relevent information. I need to >> crate wind, moisture, and fire origin files. >> >> BR, >> Vidura Dantanarayana. >> >> On Sat, Sep 1, 2018 at 7:23 PM Pedro Venâncio <[email protected]> >> wrote: >> >>> Hi Vidura, >>> >>> You need to prepare the input data to r.ros algorithm >>> >>> https://grass.osgeo.org/grass74/manuals/r.ros.html >>> >>> The input data needs to be in raster format. >>> >>> First you need to use the standard NFFL 13 fuel models system ( >>> https://www.fs.fed.us/rm/pubs/rmrs_gtr153.pdf) as fuel model input >>> raster. >>> >>> You also need the fuel moisture content for all sizes and response times >>> (dead 1h, 10h, 100h and live), in percentage. >>> >>> As Moritz explained to you, you can see that the 1hour_moisture raster >>> of the sample data is composed by: >>> >>> - 3% moisture in areas of fuel model 4; >>> - 15% moisture in areas of fuel model 8. >>> >>> You can give homogeneous fuel moisture content for each response times, >>> or different if you have that information, like in the sample data. >>> >>> Then you need an elevation raster (DEM), calculate slope and aspect (if >>> you don't have them yet, with r.slope.aspect), and a raster with wind speed >>> (in feet/minute) and another with wind direction (clockwise from north, in >>> degrees). >>> >>> With this data, you run r.ros and with the output rasters, run r.spread >>> >>> https://grass.osgeo.org/grass74/manuals/r.spread.html >>> >>> r.spread just need the an additional raster, with the >>> ignition(s)/starting sources. Pixels of starting sources raster needs to be >>> only values of 1 (ignition points/areas) and 0 (other areas). If you have >>> the ignitions in vector format, just use v.to.rast. >>> >>> I hope this helps. >>> >>> Best regards, >>> Pedro Venâncio >>> >>> >>> >>> Vidura Dantanarayana <[email protected]> escreveu no dia sábado, >>> 1/09/2018 à(s) 14:12: >>> >>>> Hi all, >>>> >>>> Thank you very much Moritz Lennert for the explanation and >>>> apologize for the mistake I've done. I will try what you suggest by >>>> myself. Hope It's okay to questioning again if I found a problem again. >>>> Have a wonderful day. Cheers!!! >>>> >>>> BR, >>>> Vidura Dantanarayana. >>>> >>>> On Sat, Sep 1, 2018 at 2:04 AM Moritz Lennert < >>>> [email protected]> wrote: >>>> >>>>> Hi Vidura, >>>>> >>>>> First of all, please keep discussions on the list. >>>>> >>>>> On 31/08/18 09:48, Vidura Dantanarayana wrote: >>>>> > Hi Moritz, >>>>> > >>>>> > Really appreciate your help as we are facing this problem for some >>>>> days >>>>> > now. First I'm a beginner user. Can you explain what are the >>>>> categories >>>>> > and how those used in GRASS GIS? >>>>> >>>>> GRASS GIS is an extremely wonderful and powerful tool, but it does >>>>> need >>>>> some initial learning in order to understand how to use it. Just >>>>> answering the questions below will not provide that for you. >>>>> >>>>> I would suggest that you go through some of the basic introductory >>>>> material, just in order to get a feeling for GRASS GIS, before >>>>> attacking >>>>> your specific problem. >>>>> >>>>> You could have a look at the following resources (at least for their >>>>> introductory parts): >>>>> >>>>> - https://grass.osgeo.org/grass74/manuals/helptext.html >>>>> - https://grass.osgeo.org/grass74/manuals/rasterintro.html >>>>> - https://grass.osgeo.org/grass74/manuals/vectorintro.html >>>>> - >>>>> >>>>> https://grasswiki.osgeo.org/wiki/From_GRASS_GIS_novice_to_power_user_(workshop_at_FOSS4G_Boston_2017) >>>>> - >>>>> >>>>> http://www.training.gismentors.eu/isprs-summer-school-2016/lesson1/grass-gis.html >>>>> >>>>> Or search for "GRASS GIS" in YouTube for some videos. >>>>> >>>>> > Let's say I need to create custom >>>>> > 1hour_moisture (or any other file), so how can I create these files? >>>>> >>>>> How you create these files depends on the data that you have as input. >>>>> >>>>> If you look at the metadata of the file in the demolocation >>>>> (right-click->Metadata or 'r.info 1hour_moisture' you will this >>>>> information at the end: >>>>> >>>>> | Data Description: >>>>> | >>>>> | generated by r.mapcalc >>>>> | >>>>> | >>>>> | >>>>> | Comments: >>>>> | >>>>> | if(fuel_class==4,3,if(fuel_class==8,15)) >>>>> >>>>> >>>>> This means that the authors had a raster file called 'fuel_class' and >>>>> used the raster calculator (r.mapcalc) to reclass that file >>>>> attributing >>>>> the value 3 to those pixels who had class=4 in the original map and >>>>> value 15 to pixels with class=8. >>>>> >>>>> I have no idea what this original map contained, so cannot help you >>>>> further (I don't know much about fire spread modeling). >>>>> >>>>> > Can >>>>> > you look at the following problem again? >>>>> > >>>>> > >>>>> > # 1 categories >>>>> -----------------------------------------------------> (1) >>>>> > Map of Fire Origin of Bass River Fire --------------------> (2) >>>>> > >>>>> > 0.00 0.00 0.00 0.00 ---------------------------------------------> >>>>> (3) >>>>> > 0:no data >>>>> -----------------------------------------------------------> (4) >>>>> > 1:fire origin >>>>> ---------------------------------------------------------> (5) >>>>> > >>>>> > I need to know how to customize the location of origin. I mean, I >>>>> want >>>>> > to ignite the fire from another place rather the place specified in >>>>> demo >>>>> > data. >>>>> >>>>> If you have the origin location as coordinates, you can create a >>>>> vector >>>>> point at the location using v.in.ascii: in the GUI of that module you >>>>> can enter coordinates interactively. Then you convert the map to a >>>>> raster map using v.to.rast. >>>>> >>>>> Moritz >>>>> >>>> _______________________________________________ >>>> grass-user mailing list >>>> [email protected] >>>> https://lists.osgeo.org/mailman/listinfo/grass-user >>> >>>
_______________________________________________ grass-user mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-user
