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I have shapefile data (of the river Tweed catchment in N England and Scotland) which I have been able to plot precipitation and temperature data onto without too many problems. These data have the OSGB 1936/British National Grid CRS projection.

But I now have a raster of land cover (from the Centre for Ecology and Hydrology) covering the catchment area which I want to incorporate into my processing. I have downloaded the raster into R and its properties are

class      : RasterLayer 
band       : 1  (of  5  bands)
dimensions : 4914, 8861, 43542954  (nrow, ncol, ncell)
resolution : 25, 25  (x, y)
extent     : 261400, 482925, 576750, 699600  (xmin, xmax, ymin, ymax)
crs        : +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +units=m +no_defs 
source     : LCM.tif 
names      : LCM 
values     : 0, 255  (min, max)

So it has a different CRS. How (in R) can I reset the raster CRS to be the same as my earlier data sets i.e., OSGB 1936 British National Grid? I haven't been able to find anything obvious on the net.

1 Answer 1

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I think that is the same CRS, only expressed as a PROJ string.

This is the OSGB CRS (you've not given us a formal statement of what you've got - is it specified by epsg:27700?):

> st_crs(27700)
Coordinate Reference System:
  User input: EPSG:27700 
  wkt:
PROJCRS["OSGB 1936 / British National Grid",

As a PROJ string that is:

> st_crs(27700)$proj4string
[1] "+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +units=m +no_defs"

which is identical to the string in your new data.

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