Hi, I still need some help. Scant progress.
Resources: I have Deepayan's "Lattice" book and Roger,
Edzer, and Virgillio's "Applied Spatial Data Analysis"
if you want to refer me to anything there.
A. I use spplot with spplot.polygon parameters I receive the
following error.
. The argument seems there and returns "iso".
. Am I missing something? My call is in section I below.
"Error in append(list(formula, data = as(sdf, "data.frame"),
aspect = aspect,: argument is missing, with no default"
B. By the way, mapasp doc could be cleaner. In the line below...
1) no opening brace to match "180)" closing brace
2) "middle of the map" the correct word is probably "median" not "mean"
"let s = 1/cos(My * pi)/180) with My the y coordinate of the middle
of the map (the mean of ylim)"
C. I would be happy to email my spatial polygon data frame if you want
to experiment.
Below is my non working spplot call. Idea is to have a 3d version
that uses the z value.
I. Errors with aspect function argument
library(sp)
library(maptools)
library(rgdal)
library(PBSmapping)
tx3_sp <- readShapePoly("tx3_sp.shp", IDvar="PCT",
proj4string=CRS("+proj=aea +ellps=GRS80 +datum=WGS84"))
spplot (
tx3_sp, # obj
c("D_CNT"), # zcol = names(obj). D_CNT has a max of 1693
, # other arguments passed to levelplot
(grids,
# polygons) or xyplot (points)
, # names, to use in panel, if different
from zcol
# names
scales = list(draw = FALSE), # scales argument to be passed to
Lattice
# plots;
xlab = NULL,
ylab = NULL,
aspect = mapasp(obj,xlim,ylim),
# aspect ratio for spatial axes;
defaults to "iso"
# (one unit on the x-axis equals one
unit on the
# y-axis) but may be set to more
suitable values
# if the data are e.g. if coordinates are
#latitude/longitude
panel = panel.polygonsplot,
# depending on the class of obj,
panel.polygonsplot
# (for polygons or lines),
panel.gridplot (grids) or
# panel.pointsplot (points) is used;
for further
# control custom panel functions
# can be supplied that call one of
these panel functions,
# but do read how the argument
sp.layout may help
sp.layout = NULL, # NULL or list; see notes below
, # formula, optional; may be useful to
plot a transformed
# value. Defaults to z~x+y for single
and z~x+y|name
# for multiple attributes; use e.g.
exp(x)~x+y|name to
# plot the exponent of the
z-variable
xlim = bbox(tx3_sp)[1, ],# numeric; x-axis limits
ylim = bbox(tx3_sp)[2, ] # numeric; y-axis limits
)
II. > summary(tx3_sp)
Object of class SpatialPolygonsDataFrame
Coordinates:
min max
r1 2488376 2542115
r2 7003736 7046215
Is projected: TRUE
proj4string :
[+proj=aea +ellps=GRS80 +datum=WGS84 +lat_1=29.5 +lat_2=45.5
+towgs84=0,0,0]
Data attributes: (I did not list these)
III. mapasp(tx3_sp,bbox(tx3_sp)[1, ],bbox(tx3_sp)[2, ])
[1] "iso"
Thanks,
Jim Burke
Jim Burke wrote:
Hi Everyone,
QUESTION: How can I plot a spatial polygon (SpatialPolygonsDataFrame)
as 3-d? Perhaps using "spplot.polygons" with its z value?
GOAL: To have a series of polygons look like approximately like the
last example in the PDF below.
http://ocw.mit.edu/NR/rdonlyres/Urban-Studies-and-Planning/11-521Spatial-Database-Management-and-Advanced-Geographic-Information-SystemsSpring2003/ACA80C9F-4089-403E-9669-50763381D08A/0/lect13c.pdf
EXAMPLE SUGGESTION: Use "spplot.pologons" with the venerable
SourceForge NC fig21.R example and using its color coding values as
the polygon $z value? Assuming lat and long are in the sp.
http://r-spatial.sourceforge.net/gallery/#fig21.R
Then if its not as straightforward as above, what would be the steps
to convert a spatial polygon to points or something to graph that way?
Thanks,
Jim Burke
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