[R-SIG-Mac] Dramatically slow map plotting

[David Winsemius]

On Mar 20, 2014, at 4:56 PM, Rolando Valdez wrote:

> Hello, 
> 
> Recently, I acquired a MacBook Pro, Core i7, 8 GB ram.


> I Installed the newest R version, 3.0.3 from the web page. The problem is when I’m plotting maps, because is going very, very slow, about 3 or 4 minutes just for a single map, while I’ve done this in a few seconds in Windows with Core i5 and 4 GB ram.
> 
> This is what I have:
> 
> R version 3.0.3 (2014-03-06) -- "Warm Puppy"
> Copyright (C) 2014 The R Foundation for Statistical Computing
> Platform: x86_64-apple-darwin10.8.0 (64-bit)
> 
> [R.app GUI 1.63 (6660) x86_64-apple-darwin10.8.0]
> 
> I found a reproducible example in web and I took time with proc.time()
> 
> ptm <- proc.time()

Most people use system.time and not proc.time.

When you execute proc.time you get something like:

> proc.time()
     user    system   elapsed 
   75.736    33.765 97374.066 

Is that meaningful to you? (It's not to me.)

When I wrap system.time around that set of expressions (inside RStudio on a 6 year-old MacPro) I get:

   user  system elapsed 
  0.065   0.001   0.066 

-- 
David.

> library(sp)
> library(lattice) # required for trellis.par.set():
> trellis.par.set(sp.theme()) # sets color ramp to bpy.colors()
> 
> # prepare nc sids data set:
> library(maptools)
> nc <- readShapePoly(system.file("shapes/sids.shp", package="maptools")[1], proj4string=CRS("+proj=longlat +datum=NAD27"))
> arrow = list("SpatialPolygonsRescale", layout.north.arrow(),
> offset = c(-76,34), scale = 0.5, which = 2)
> #scale = list("SpatialPolygonsRescale", layout.scale.bar(),
> #    offset = c(-77.5,34), scale = 1, fill=c("transparent","black"), which = 2)
> #text1 = list("sp.text", c(-77.5,34.15), "0", which = 2)
> #text2 = list("sp.text", c(-76.5,34.15), "1 degree", which = 2)
> ## multi-panel plot with filled polygons: North Carolina SIDS
> spplot(nc, c("SID74", "SID79"), names.attr = c("1974","1979"),
> colorkey=list(space="bottom"), scales = list(draw = TRUE),
> main = "SIDS (sudden infant death syndrome) in North Carolina",
> sp.layout = list(arrow), as.table = TRUE)
> 
> #    sp.layout = list(arrow, scale, text1, text2), as.table = TRUE)
> proc.time() - ptm
> 
> user  system elapsed 
> 2.408   0.064   2.616
> 
> It was quick.
> 
> Then I did a single plot with my shape:
> 
> mapa <- readShapePoly(“Entidades_2013.shp”)
> ptm <- proc.time()
> spplot(mapa[1]); proc.time() - ptm
> 
> user  system elapsed 
> 87.575   0.786  88.068
> 
> Why it take a lot of time? I worked with same shapes in Windows and never took that time.
> 
> Hope you can help me,
> 
> Regards,
> Rolando Valdez
> 
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David Winsemius
Alameda, CA, USA