[R-sig-Geo] Decision tree classification of satellite image in R

[Jonathan Greenberg]

Anusheema:

If you do want to use the RWeka classifier, you can write a function
in rasterEngine (part of spatial.tools) to use it -- you basically
need to coerce its output back into an array, which shouldn't be too
hard to do.

--j

On Tue, May 6, 2014 at 11:32 PM, Anusheema Chakraborty
<anusheema at gmail.com> wrote:
> Yes, I realized that later. RandomForest is available to predict fitted
> model to raster data, but not RWeka classifier. However, Rpart works too.
>
> Thanks!
>
>
> On Tue, May 6, 2014 at 9:22 PM, Jonathan Greenberg <jgrn at illinois.edu>
> wrote:
>>
>> Anusheema:
>>
>> The first error is because you didn't specify an out filename (it
>> needs to be a character).
>>
>> Re: the second error -- is there a predict.R_Weka_classifier_interface
>> (or something along those lines) in that package?  For predict to
>> work, you need a predict.* statement available.
>>
>> You might want to swap in a randomForest for the classifier you are
>> using, at least to begin with -- randomForest does work properly with
>> raster's predict() statement.
>>
>> --j
>>
>> On Tue, May 6, 2014 at 1:37 AM, Anusheema Chakraborty
>> <anusheema at gmail.com> wrote:
>> > Hi!
>> >
>> > I am trying to classify satellite image in R using RWeka classifier,
>> > J48. I have a CSV file with the classes required, and raster data
>> > loaded in R. I am able to make the tree, however, I am not able to use
>> > the same tree to classify my satellite image.
>> >
>> > Here's how it goes.
>> >
>> > inputfile=read.csv("E://R/Trial/naini.CSV")
>> > m1 <- J48(Class~B1+B2+B3+B4+B5+B7, data = inputfile)
>> > if(require("party", quietly = TRUE)) plot(m1)
>> > raster<- brick("merge.tif")
>> > plotRGB(raster, 4, 3, 2, stretch="hist")
>> >
>> > And then I am attempting to use the tree generated to classify my
>> > satellite image, but I keep getting errors.
>> >
>> > predict (test_new, J48, filename=out_classify,
>> > progress='text',format='GTiff', datatype='FLT4S', type='response',
>> > overwrite=TRUE)
>> > Error in trim(filename) : error in evaluating the argument 'x' in
>> > selecting a method for function 'trim': Error: object 'out_classify'
>> > not found
>> >
>> > And if I change the arguments, this is what I get. I am not sure how
>> > to proceed from this point forward.
>> >
>> > predict (J48, test_new, filename=out_classify,
>> > progress='text',format='GTiff', datatype='FLT4S', type='response',
>> > overwrite=TRUE)
>> > Error in UseMethod("predict") : no applicable method for 'predict'
>> > applied to an object of class "c('R_Weka_classifier_interface',
>> > 'R_Weka_interface')"
>> >
>> > I am new to R, so I might take a while to decipher your answers. Any
>> > help would be greatly appreciated!
>> >
>> > Thanks!
>> >
>> >
>> > Best,
>> > Anusheema.
>> >
>> >
>> >
>> > --
>> > Regards
>> >
>> > Anusheema Chakraborty
>> > Ph.D. Scholar
>> > Department of Natural Resources, TERI University
>> > 10, Institutional Area, Vasant Kunj, New Delhi - 110070
>> > Website: www.teriuniversity.ac.in
>> >
>> > _______________________________________________
>> > R-sig-Geo mailing list
>> > R-sig-Geo at r-project.org
>> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>
>>
>>
>> --
>> Jonathan A. Greenberg, PhD
>> Assistant Professor
>> Global Environmental Analysis and Remote Sensing (GEARS) Laboratory
>> Department of Geography and Geographic Information Science
>> University of Illinois at Urbana-Champaign
>> 259 Computing Applications Building, MC-150
>> 605 East Springfield Avenue
>> Champaign, IL  61820-6371
>> Phone: 217-300-1924
>> http://www.geog.illinois.edu/~jgrn/
>> AIM: jgrn307, MSN: jgrn307 at hotmail.com, Gchat: jgrn307, Skype: jgrn3007
>
>
>
>
> --
> Regards
>
> Anusheema Chakraborty
> Ph.D. Scholar
> Department of Natural Resources, TERI University
> 10, Institutional Area, Vasant Kunj, New Delhi - 110070
> Website: www.teriuniversity.ac.in



-- 
Jonathan A. Greenberg, PhD
Assistant Professor
Global Environmental Analysis and Remote Sensing (GEARS) Laboratory
Department of Geography and Geographic Information Science
University of Illinois at Urbana-Champaign
259 Computing Applications Building, MC-150
605 East Springfield Avenue
Champaign, IL  61820-6371
Phone: 217-300-1924
http://www.geog.illinois.edu/~jgrn/
AIM: jgrn307, MSN: jgrn307 at hotmail.com, Gchat: jgrn307, Skype: jgrn3007