[prev in list] [next in list] [prev in thread] [next in thread] 

List:       grass-stats
Subject:    Re: [GRASS-stats] Error slot - spgrass6
From:       Roger Bivand <Roger.Bivand () nhh ! no>
Date:       2011-08-22 7:38:39
Message-ID: alpine.LRH.2.00.1108220936490.10038 () reclus ! nhh ! no
[Download RAW message or body]

On Mon, 22 Aug 2011, Gaspar Reyes Póndigo wrote:

> Hi, Dear Grass-stats users
> 
> I am new user R 2.13 (spgrass6) from GRASS-GIS 6.4.1-5, under Mac OS X 
> 10.68. I have the following problem, when preparing the data before run 
> R's princomp() function in R from GRASS, there was an error. The line of 
> code is copied below:
> 

Please only post to one list at a time, and wait patiently for an answer.


> 
> #########################################
> library(spgrass6)
> 
> G <- gmeta6()
> 
> ATC <- readRAST6(c('Acrf_1993_b1','Acrf_1993_b2','Acrf_1993_b3','Acrf_1993_b4','Acrf_1993_b5','Acrf_1993_b7'))
>  
> ATC.nas <- which(is.na(ATC@data$Acrf_1993_b1) & is.na(ATC@data$Acrf_1993_b2) & \
> is.na(ATC@data$Acrf_1993_b3) & is.na(ATC@data$Acrf_1993_b4) & \
> is.na(ATC@data$Acrf_1993_b5) & is.na(ATC@data$Acrf_1993_b7))

Never access columns with ...@data$... which is exactly the same as 
...$...

> 
> ATC.ms.values <- which(!is.na(ATC@data$Acrf_1993_b1) & \
> !is.na(ATC@data$Acrf_1993_b2) & !is.na(ATC@data$Acrf_1993_b3) & \
> !is.na(ATC@data$Acrf_1993_b4) & !is.na(ATC@data$Acrf_1993_b5) & \
> !is.na(ATC@data$Acrf_1993_b7)) 
> #######################################
> ####  I got the following error message
> #######################################
> ATC.ms.nonas <- ATC.ms.values@data[ATC.ms.values, ]

str(ATC.ms.values) is certainly integer. I believe that you want to say
either (may need casting to SpatialPixelsDataFrame first):

ATC.ms.nonas <- ATC[ATC.ms.values,]

or

ATC.ms.nonas <- as(ATC, "data.frame")[ATC.ms.values,]


> Error: tentativa de obtener un slot "data" de un objeto de una clase 
> básica ("integer") sin slots

which is very clear. Do use str() or class() to check the objects you are
using.

Roger

> 
#########################################
> 
> Can you please point my problem? and How do I fix my problem?
> Thanks in advance for any help.
> 
> NOTE:I followed the guide of \
> http://grass.osgeo.org/wiki/Principal_Components_Analysis # \
>                 Using_R.27s_princomp.28.29_function for  PRINCOMP() function.
> NOTE: the images are LANDSAT 5 TM
> 
> 
> Gaspar Reyes Póndigo
> Universidad del Mar, Oaxaca, México
> Campus Puerto-Ángel
> Carretera principal Puerto Ángel Zipolite km 1.5
> C.P. 70902_______________________________________________
> grass-stats mailing list
> grass-stats@lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/grass-stats
> 

-- 
Roger Bivand
Department of Economics, NHH Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand@nhh.no



_______________________________________________
grass-stats mailing list
grass-stats@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-stats


[prev in list] [next in list] [prev in thread] [next in thread]