CODEWITHSUNDEEP
rspatialrasterr-raster
Joseph Lewis
Joseph Lewis

Reputation: 173

How to get point coordinates in same projection as raster

I'm trying to plot some points on a raster (which has a OSGB36 projection), but the points x and y positions are in a different extent to the plotted raster. How can I get the points to be in the same coordinate system/extent as the raster, so they appear on the raster.

The raster layer crs:

extent      : 420000, 480000, 440000, 5e+05  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +datum=OSGB36 +units=m +no_defs +ellps=airy +towgs84=446.448,-125.157,542.060,0.1502,0.2470,0.8421,-20.4894

plotted raster:

enter image description here

Yet the x/y positions of the points (which are also in OSGB6) are:

54, -1.3

Any ideas on what I may have done wrong/how to fix it?

Thanks!

Upvotes: 1

Views: 1249

Answers (1)

Sébastien Rochette
Sébastien Rochette

Reputation: 6661

Your point seems to be in wgs84 geographical coordinates and not in projected Osgb6. You probably misspecified the crs in Arcgis. You need to modify the crs of your point. I assume your raster is called r:

pt <- data.frame(x=54,y= -1.3)
coordinates(pt) <- ~x+y
projection(pt) <- "+init:epsg=4326"
pt_osgb <- spTransform(pt, CRS(projection(r)))

By the way, you know that you can get coordinates of a point in R while using function locator(sp=TRUE).

Sorry, I am with my smartphone, I cannot test this script but I think this may be the reason...

Upvotes: 1

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