Two short questions about working with maps:
1. I'm reading a shapefile with character labels for the regions
(FSA). I can add the labels using plot(),
but when I try the same thing using spplot(), the labels are in the
wrong positions -- they all seem to be
shrunk somewhat in toward the center of the map. What am I doing wrong?
library(maptools)
# using readShapeSpatial
ontario <-readShapeSpatial("ForwardSortationAreas_JUL07_ON_region.shp",
IDvar="FSA", proj4string=CRS("+proj=longlat +datum=NAD83") )
toronto <- ontario[ontario$F=="M",]
summary(toronto)
# this works OK
plot(toronto)
text(coordinates(toronto), labels=as.character(toronto$FSA), cex=0.4)
# this doesn't work-- labels in wrong position
spplot(toronto,"FSA_NAME", colorkey=FALSE)
text(coordinates(toronto), labels=as.character(toronto$FSA), cex=0.4)
2. I have a bunch of attribute variables for the geographic regions, all
on different scales. Id like to
produce a set of comparative maps in the same figure (say with spplot())
with each attribute shaded
by its quantiles, e.g., 5 classes each. Do I have to precompute these
first, or is there something I can do in the call
to spplot() to have this done, using the variables in the
SpatialPolygonsDataFrame?
> toronto <- spCbind(toronto, crimeTO)
> summary(toronto)
Object of class SpatialPolygonsDataFrame
Coordinates:
min max
r1 -79.63925 -79.11484
r2 43.58103 43.85547
Is projected: FALSE
proj4string : [+proj=longlat +datum=NAD83]
Data attributes:
FSA FSA_NAME F PR Area
Jail.Cost Rank
M1B : 1 TORONTO :48 K: 0 35:102 Toronto :39 Min.
: 0 Min. : 6.0
M1C : 1 NORTH YORK :22 L: 0 North York :24 1st
Qu.: 3205 1st Qu.:126.8
M1E : 1 SCARBOROUGH:17 M:102 Scarborough:17 Median
: 42249 Median :296.5
M1G : 1 ETOBICOKE :12 N: 0 Etobicoke :12 Mean
: 84991 Mean :259.7
M1H : 1 EAST YORK : 3 P: 0 East York : 5 3rd
Qu.:139404 3rd Qu.:406.0
M1J : 1 ACTON : 0 York : 5 Max.
:506339 Max. :413.0
(Other):96 (Other) : 0 (Other) :
0
Inmates Inmates.per.10K Days.Sentenced Population
Household.Income
Min. : 0.000 Min. :0.000 Min. : 0.0 Min. : 0
Min. : 35129
1st Qu.: 1.000 1st Qu.:0.325 1st Qu.: 30.0 1st Qu.:15857 1st
Qu.: 48438
Median : 3.000 Median :1.000 Median : 395.5 Median :23564
Median : 58015
Mean : 3.559 Mean :1.180 Mean : 795.6 Mean :25161
Mean : 62123
3rd Qu.: 5.000 3rd Qu.:1.800 3rd Qu.:1305.0 3rd Qu.:34878 3rd
Qu.: 66259
Max. :15.000 Max. :4.300 Max. :4740.0 Max. :66878
Max. :127669
NA's : 5
Low.Income Unemployed University Female.Homes
Public.Housing
Min. : 6.00 Min. :2.000 Min. : 8.00 Min. : 8.00 Min.
: 2
1st Qu.:15.00 1st Qu.:4.000 1st Qu.:20.00 1st Qu.:13.00 1st
Qu.: 234
Median :20.00 Median :5.000 Median :28.00 Median :16.00 Median
: 685
Mean :20.05 Mean :5.412 Mean :31.31 Mean :16.16 Mean
: 995
3rd Qu.:25.00 3rd Qu.:7.000 3rd Qu.:45.00 3rd Qu.:19.00 3rd
Qu.:1276
Max. :41.00 Max. :9.000 Max. :64.00 Max. :30.00 Max.
:9289
NA's : 5.00 NA's :5.000 NA's : 5.00 NA's : 5.00 NA's
: 27
>
--
Michael Friendly Email: friendly AT yorku DOT ca
Professor, Psychology Dept.
York University Voice: 416 736-5115 x66249 Fax: 416 736-5814
4700 Keele Street http://www.math.yorku.ca/SCS/friendly.html
Toronto, ONT M3J 1P3 CANADA
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