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How can I plot a "raster" object behind a shapefile object? Both plot fine on their own but the points don't plot over the raster:
require(rgdal)
require(maptools)
require(raster)
myproj = "+proj=utm +zone=12 +north +ellps=WGS84 +units=m"
shp = readShapeSpatial(fn.shp, proj4string = CRS(myproj))
ras = raster(fn.tif)
plot(ras)
plot(shp, bg="transparent", add=TRUE)
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Format Plot If we need to create multiple plots using the same color palette, we can create an R object ( myCol ) for the set of colors that we want to use. We can then quickly change the palette across all plots by simply modifying the myCol object. We can label the x- and y-axes of our plot too using xlab and ylab .
A raster plot is a simple method to visually examine the trial-by-trial variability of the respones. You can examine what features these responses have in common by averaging over all responses to create a peri-stimulus time histogram.
Overplotting raster plots with points, lines, and polygons should work just fine, as the following example shows.
My best guess would be that the Spatial* objects you are attempting to plot on top of the raster fall outside of the region being plotted. Have you checked that both the raster and Spatial* objects are in the same CRS, and (assuming they are) that the bounding boxes overlap? (i.e. try bbox(shp) and bbox(ras), and compare the results).
library(rgdal)
library(raster)
# Create a raster
ras <- raster(ncols=36, nrows=18)
ras[] <- runif(ncell(ras))
# Create a SpatialPoints object
shpPts <- spsample(Spatial(bbox=bbox(ras)), 20, type="random")
# Create a SpatialPolygons object
p1 <- rbind(c(-10,0), c(140,60), c(160,0), c(140,-55), c(-10,0))
shpPolys <- SpatialPolygons( list(Polygons(list(Polygon(p1)), 1)))
# Plot them, one layer after another
plot(ras)
plot(shpPts, pch=16, col="red", add=TRUE)
plot(shpPolys, col="yellow", add=TRUE)
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