[STATSGRASS] import DTM with readRAST6()

Matteo Dall'Amico matteo.dallamico at ing.unitn.it
Tue Jul 10 15:12:09 EDT 2007 

Hello Carlos,
I tried to transform the DTM in integer values through the command:  
r.out.ascii -i

then I did again the import with readRAST6() but the result is the same:

 > summary(trent.grid.integer)
Object of class SpatialGridDataFrame
Coordinates:
               min     max
coords.x1 1611600 1729700
coords.x2 5058500 5158000
Is projected: TRUE
proj4string :
[+proj=tmerc +lat_0=0.0000000000 +lon_0=9.0000000000 +k_0=0.9996000000
+x_0=1500000.0000000000 +y_0=0.0000000000 +a=6378388 +rf=297 +no_defs
+towgs84=-225.000,-65.000,9.000]
Number of points: 2
Grid attributes:
   cellcentre.offset cellsize cells.dim
1           1611650      100      1181
2           5058550      100       995
Data attributes:
DTM_trent_100m
Min.   :1.192e-319
1st Qu.:1.065e-314
Median :1.066e-314
Mean   :1.285e-312
3rd Qu.:2.722e-312
Max.   :4.774e-312


As you see, I didn't obtain a good import, as the elevation values  
are still strange...
Any idea?

Matteo

On 9 Jul 2007, at 16:40, Carlos Guâno Grohmann wrote:

> I just tested here in grass 6.2.1 (ubuntu package), it worked fine.
>
> I see you have some very "precise" elevation readings:
> 370.84381103515625....
>
> and that in the import process, data is exported as double (bytes=8),
> maybe this is the problem?
>
> any way you can get that elevations with less decimal values?
>
> just a guess, but..
>
> Carlos
>
>
>
>
>
>
> On 7/9/07, Matteo Dall'Amico <matteo.dallamico at ing.unitn.it> wrote:
>> Hi Carlos,
>> thank you for your reply.
>> I think the problem is that the import was not successful. As you see
>> from data attributes,
>>
>> Data attributes:
>> DTM_trentino_100m
>> Min.   :1.192e-319
>> 1st Qu.:1.065e-314
>> Median :1.066e-314
>> Mean   :1.285e-312
>> 3rd Qu.:2.722e-312
>> Max.   :4.774e-312
>>
>> the elevations are not correct. I would expect values ranging between
>> 60 and 3500m and not from 1.192e-319 to 4.774e-312.
>> I think the problem lays in the import procedure during readRAST6().
>> Any suggestion?
>> Thanks in advance,
>> Matteo
>>
>> On 9 Jul 2007, at 15:41, Carlos Guâno Grohmann wrote:
>>
>> > try to
>> > str(trentino.grid)
>> >
>> > the summary() you want is probably
>> >
>> > summary(trentino.grid$DTM_trentino_100m)
>> >
>> > hope this helps
>> > Carlos
>> >
>> >
>> >
>> > On 7/9/07, Matteo Dall'Amico <matteo.dallamico at ing.unitn.it> wrote:
>> >>
>> >> Hello everybody,
>> >> I am a new R & Grass user.
>> >> I am interested in doing a kriging of the Temperature in a basin,
>> >> based on
>> >> pixel elevation (DTM).
>> >> I use Grass 6.2.1 and R 2.5.1 and have installed the spgrass6
>> >> package.
>> >>
>> >> The DTM is called "DTM_trentino_100m" and has a header and data
>> >> like the
>> >> following:
>> >>
>> >> north:5158000.0
>> >> south:5058500.0
>> >> east:1729700.0
>> >> west:1611600.0
>> >> rows:995
>> >> cols:1181
>> >> -9999.0 -9999.0 -9999.0 370.84381103515625 372.55120849609375
>> >> 373.13128662109375 .....
>> >>
>> >> I have opened R inside the Grass location, and imported the DTM:
>> >>
>> >> >  trentino.grid<-readRAST6("DTM_trentino_100m")
>> >> Creating BIL support files ...
>> >> Header File =
>> >> /Users/Matteo/Documents/DataGrass/GBovest/Permafrost/.tmp/
>> >> nilo.local/DTM_trentino_100m.hdr
>> >> World File =
>> >> /Users/Matteo/Documents/DataGrass/GBovest/Permafrost/.tmp/
>> >> nilo.local/DTM_trentino_100m.wld
>> >> Exporting Raster as double values(bytes=8)
>> >> Using the Current Region settings ...
>> >> north=5158000.000000
>> >> south=5058500.000000
>> >> east=1729700.000000
>> >> west=1611600.000000
>> >> r=995
>> >> c=1181
>> >>
>> >> Percent complete:  100%
>> >> r.out.bin complete.
>> >>
>> >> > summary(trentino.grid)
>> >> Object of class SpatialGridDataFrame
>> >> Coordinates:
>> >>               min     max
>> >> coords.x1 1611600 1729700
>> >> coords.x2 5058500 5158000
>> >> Is projected: TRUE
>> >> proj4string :
>> >> [+proj=tmerc +lat_0=0.0000000000 +lon_0=9.0000000000
>> >> +k_0=0.9996000000
>> >> +x_0=1500000.0000000000 +y_0=0.0000000000 +a=6378388 +rf=297  
>> +no_defs
>> >> +towgs84=-225.000,-65.000,9.000]
>> >> Number of points: 2
>> >> Grid attributes:
>> >>   cellcentre.offset cellsize cells.dim
>> >> 1           1611650      100      1181
>> >> 2           5058550      100       995
>> >> Data attributes:
>> >> DTM_trentino_100m
>> >> Min.   :1.192e-319
>> >> 1st Qu.:1.065e-314
>> >> Median :1.066e-314
>> >> Mean   :1.285e-312
>> >> 3rd Qu.:2.722e-312
>> >> Max.   :4.774e-312
>> >>
>> >> As you can see, the import has been fully done, yet the attributes
>> >> are not
>> >> correct. In fact, the Min. value is 1.192e-319 and the Max is
>> >> 4.774e-312 but
>> >> in reality the elevation changes between 60m to 3500m.
>> >> Have I done something wrong? What should I do?
>> >> Thank you in advance,
>> >>
>> >> Matteo
>> >>
>> >>
>> >> ---------------------------------
>> >> Matteo Dall'Amico
>> >> PhD candidate
>> >> CUDAM and department of Civil and Environmental Engineering
>> >> Universita' degli Studi di Trento
>> >> Via Mesiano 77 - 38050 Trento - Italy
>> >> email: matteo.dallamico at ing.unitn.it
>> >> Tel. +39 0461 882610
>> >> Fax +39 0461 882672
>> >> http://www.dottorato.it/trento/
>> >> ---------------------------------
>> >>
>> >>
>> >> _______________________________________________
>> >> statsgrass mailing list
>> >> statsgrass at grass.itc.it
>> >> http://grass.itc.it/mailman/listinfo/statsgrass
>> >>
>> >>
>> >
>> >
>> > --
>> > +-----------------------------------------------------------+
>> >              Carlos Henrique Grohmann - Guano
>> >  Visiting Researcher at Kingston University London - UK
>> >  Geologist M.Sc  - Doctorate Student at IGc-USP - Brazil
>> > Linux User #89721  - carlos dot grohmann at gmail dot com
>> > +-----------------------------------------------------------+
>> > _________________
>> > "Good morning, doctors. I have taken the liberty of removing  
>> Windows
>> > 95 from my hard drive."
>> > --The winning entry in a "What were HAL's first words" contest  
>> judged
>> > by 2001: A SPACE ODYSSEY creator Arthur C. Clarke
>> >
>> > _______________________________________________
>> > statsgrass mailing list
>> > statsgrass at grass.itc.it
>> > http://grass.itc.it/mailman/listinfo/statsgrass
>> >
>>
>>
>
>
> -- 
> +-----------------------------------------------------------+
>              Carlos Henrique Grohmann - Guano
>  Visiting Researcher at Kingston University London - UK
>  Geologist M.Sc  - Doctorate Student at IGc-USP - Brazil
> Linux User #89721  - carlos dot grohmann at gmail dot com
> +-----------------------------------------------------------+
> _________________
> "Good morning, doctors. I have taken the liberty of removing Windows
> 95 from my hard drive."
> --The winning entry in a "What were HAL's first words" contest judged
> by 2001: A SPACE ODYSSEY creator Arthur C. Clarke
>
> _______________________________________________
> statsgrass mailing list
> statsgrass at grass.itc.it
> http://grass.itc.it/mailman/listinfo/statsgrass
>

More information about the grass-stats mailing list