Re: [R-sig-Geo] How to resample a map using the statistical mode of class to fill the new pixel

2016-08-28 Thread Bacou, Melanie 

Sorry I meant reproject using nearest neighbor:

projectRaster(from, to, method="ngb")

On 8/28/2016 2:37 AM, Bacou, Melanie wrote:

Isaque,
If your LandScan raster is at 30m resolution, then best might be to
`aggregate()` to as close as 250m (e.g. using `fact=8` or `fact=9` and
`fun=modal`), and then use `projectRaster()`:

projectRaster(from, to, method="bilinear")

Others might have better ideas.
--Mel.


On 8/26/2016 10:43 PM, Tom Philippi wrote:

Mel's answer is complete if you are aggregating to an integer multiple
of grid cells: if your tree cover was 5, 10, 25, 50, 125, etc., m
pixels.  If you are unlucky enough to have your tree cover in 15 or
30m pixels, you may need to disaggregate to greatest common factor (5
or 10m) cells first, then aggregate up to 250m MODIS.  With mode on
categorical data, that should still give you your expected results;
with continuous raster values and other functions, it might not be
appropriate.

Tom 2


On Fri, Aug 26, 2016 at 7:28 PM, Bacou, Melanie > wrote:

 Isaque, check this thread on StackExchange:
 
http://gis.stackexchange.com/questions/177423/r-aggregate-raster-with-mode-function-how-does-it-work
 


 --Mel.


 On 8/26/2016 10:07 PM, Isaque Daniel wrote:
 > Hi dear all,
 >
 >
 > I need to resample a tree cover map create by Landsat imagery to
 the MODIS 250 meters.
 >
 > If I use the resample function of raster package, it will
 compute the value based on bilinear or ngb, in this condition the
 new class map will not answer my expectations.
 >
 >
 > I loking for a way of resample using the statistical mode to
 define the value of the pixel of the new map.
 >
 >
 > Some tip about this?
 >
 > Thanks
 > Isaque
 >
 >
 >
 >
 
--
 > Agronomist engineer
 > Master in Remote Sensing - National  Institute for Space
 Research (INPE) - Brazil
 > PHD Student in Transport - Bras�lia University (UNB)
 >
 >   [[alternative HTML version deleted]]
 >
 >
 >
 > ___
 > R-sig-Geo mailing list
 > R-sig-Geo@r-project.org 
 > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
 


 [[alternative HTML version deleted]]

 ___
 R-sig-Geo mailing list
 R-sig-Geo@r-project.org 
 https://stat.ethz.ch/mailman/listinfo/r-sig-geo
 




[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo


___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] How to resample a map using the statistical mode of class to fill the new pixel

2016-08-28 Thread Bacou, Melanie 
Isaque,
If your LandScan raster is at 30m resolution, then best might be to 
`aggregate()` to as close as 250m (e.g. using `fact=8` or `fact=9` and 
`fun=modal`), and then use `projectRaster()`:

projectRaster(from, to, method="bilinear")

Others might have better ideas.
--Mel.


On 8/26/2016 10:43 PM, Tom Philippi wrote:
> Mel's answer is complete if you are aggregating to an integer multiple 
> of grid cells: if your tree cover was 5, 10, 25, 50, 125, etc., m 
> pixels.  If you are unlucky enough to have your tree cover in 15 or 
> 30m pixels, you may need to disaggregate to greatest common factor (5 
> or 10m) cells first, then aggregate up to 250m MODIS.  With mode on 
> categorical data, that should still give you your expected results; 
> with continuous raster values and other functions, it might not be 
> appropriate.
>
> Tom 2
>
>
> On Fri, Aug 26, 2016 at 7:28 PM, Bacou, Melanie  > wrote:
>
> Isaque, check this thread on StackExchange:
> 
> http://gis.stackexchange.com/questions/177423/r-aggregate-raster-with-mode-function-how-does-it-work
> 
> 
>
> --Mel.
>
>
> On 8/26/2016 10:07 PM, Isaque Daniel wrote:
> > Hi dear all,
> >
> >
> > I need to resample a tree cover map create by Landsat imagery to
> the MODIS 250 meters.
> >
> > If I use the resample function of raster package, it will
> compute the value based on bilinear or ngb, in this condition the
> new class map will not answer my expectations.
> >
> >
> > I loking for a way of resample using the statistical mode to
> define the value of the pixel of the new map.
> >
> >
> > Some tip about this?
> >
> > Thanks
> > Isaque
> >
> >
> >
> >
> 
> --
> > Agronomist engineer
> > Master in Remote Sensing - National  Institute for Space
> Research (INPE) - Brazil
> > PHD Student in Transport - Bras�lia University (UNB)
> >
> >   [[alternative HTML version deleted]]
> >
> >
> >
> > ___
> > R-sig-Geo mailing list
> > R-sig-Geo@r-project.org 
> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> 
>
>
> [[alternative HTML version deleted]]
>
> ___
> R-sig-Geo mailing list
> R-sig-Geo@r-project.org 
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> 
>
>


[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] How to resample a map using the statistical mode of class to fill the new pixel

2016-08-26 Thread Tom Philippi 
Mel's answer is complete if you are aggregating to an integer multiple of
grid cells: if your tree cover was 5, 10, 25, 50, 125, etc., m pixels.  If
you are unlucky enough to have your tree cover in 15 or 30m pixels, you may
need to disaggregate to greatest common factor (5 or 10m) cells first, then
aggregate up to 250m MODIS.  With mode on categorical data, that should
still give you your expected results; with continuous raster values and
other functions, it might not be appropriate.

Tom 2


On Fri, Aug 26, 2016 at 7:28 PM, Bacou, Melanie  wrote:

> Isaque, check this thread on StackExchange:
> http://gis.stackexchange.com/questions/177423/r-aggregate-
> raster-with-mode-function-how-does-it-work
>
> --Mel.
>
>
> On 8/26/2016 10:07 PM, Isaque Daniel wrote:
> > Hi dear all,
> >
> >
> > I need to resample a tree cover map create by Landsat imagery to the
> MODIS 250 meters.
> >
> > If I use the resample function of raster package, it will compute the
> value based on bilinear or ngb, in this condition the new class map will
> not answer my expectations.
> >
> >
> > I loking for a way of resample using the statistical mode to define the
> value of the pixel of the new map.
> >
> >
> > Some tip about this?
> >
> > Thanks
> > Isaque
> >
> >
> >
> > 
> --
> > Agronomist engineer
> > Master in Remote Sensing - National  Institute for Space Research (INPE)
> - Brazil
> > PHD Student in Transport - Bras�lia University (UNB)
> >
> >   [[alternative HTML version deleted]]
> >
> >
> >
> > ___
> > R-sig-Geo mailing list
> > R-sig-Geo@r-project.org
> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
>
> [[alternative HTML version deleted]]
>
> ___
> R-sig-Geo mailing list
> R-sig-Geo@r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo

[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] How to resample a map using the statistical mode of class to fill the new pixel

2016-08-26 Thread Bacou, Melanie 
Isaque, check this thread on StackExchange:
http://gis.stackexchange.com/questions/177423/r-aggregate-raster-with-mode-function-how-does-it-work

--Mel.


On 8/26/2016 10:07 PM, Isaque Daniel wrote:
> Hi dear all,
>
>
> I need to resample a tree cover map create by Landsat imagery to the MODIS 
> 250 meters.
>
> If I use the resample function of raster package, it will compute the value 
> based on bilinear or ngb, in this condition the new class map will not answer 
> my expectations.
>
>
> I loking for a way of resample using the statistical mode to define the value 
> of the pixel of the new map.
>
>
> Some tip about this?
>
> Thanks
> Isaque
>
>
>
> --
> Agronomist engineer
> Master in Remote Sensing - National  Institute for Space Research (INPE) - 
> Brazil
> PHD Student in Transport - Bras�lia University (UNB)
>
>   [[alternative HTML version deleted]]
>
>
>
> ___
> R-sig-Geo mailing list
> R-sig-Geo@r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo


[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo