[R] Memory limit problem

[Tim Clark]

Dear List,

I am trying to plot bathymetry contours around the Hawaiian Islands using the 
package rgdal and PBSmapping.  I have run into a memory limit when trying to 
combine two fairly small objects using cbind().  I have increased the memory to 
4GB, but am being told I can't allocate a vector of size 240 Kb.  I am running R 
2.11.1 on a Dell Optiplex 760 with Windows XP.  I have pasted the error message 
and summaries of the objects below.  Thanks for your help.  Tim


>     xyz<-cbind(hi.to.utm,z=b.depth$z)
Error: cannot allocate vector of size 240 Kb

> memory.limit()
[1] 4000
> memory.size()
[1] 1971.68

> summary(hi.to.utm)
Object of class SpatialPoints
Coordinates:
        min       max
x  708745.5  923406.7
y 2046153.1 2327910.9
Is projected: TRUE 
proj4string :
[+proj=utm +zone=4 +datum=NAD83 +ellps=GRS80 +towgs84=0,0,0]
Number of points: 15328

> str(hi.to.utm)
Formal class 'SpatialPoints' [package "sp"] with 3 slots
  ..@ coords     : num [1:15328, 1:2] 708746 710482 712218 713944 715681 ...
  .. ..- attr(*, "dimnames")=List of 2
  .. .. ..$ : NULL
  .. .. ..$ : chr [1:2] "x" "y"
  ..@ bbox       : num [1:2, 1:2] 708746 2046153 923407 2327911
  .. ..- attr(*, "dimnames")=List of 2
  .. .. ..$ : chr [1:2] "x" "y"
  .. .. ..$ : chr [1:2] "min" "max"
  ..@ proj4string:Formal class 'CRS' [package "sp"] with 1 slots
  .. .. ..@ projargs: chr " +proj=utm +zone=4 +datum=NAD83 +ellps=GRS80 
+towgs84=0,0,0"


> summary(b.depth)
       x                y               z        
 Min.   :-157.0   Min.   :18.50   Min.   :-5783  
 1st Qu.:-156.6   1st Qu.:18.98   1st Qu.:-4565  
 Median :-156.1   Median :19.80   Median :-3358  
 Mean   :-156.1   Mean   :19.73   Mean   :-3012  
 3rd Qu.:-155.5   3rd Qu.:20.41   3rd Qu.:-1601  
 Max.   :-155.0   Max.   :21.00   Max.   :    0  

> str(b.depth)
'data.frame':   15328 obs. of  3 variables:
 $ x: num  -157 -157 -157 -157 -157 ...
 $ y: num  21 21 21 21 21 ...
 $ z: num  -110 -114 -110 -88 -76 -122 -196 -224 -240 -238 ...

 

Tim Clark
Marine Ecologist
National Park of American Samoa