[R-sig-Geo] quick projection question

[Julie Lee-Yaw]

Hi,

I am trying to reproject a shapefile in R. The current projection that I am using is a lambert equal area projection defined by the proj4string:

+proj=laea +lat_0=90 +lon_0=-100 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs

I've since decided that it would be better for my calculations (areas of polygons in Canada) if the projection was centred at 60 degrees latitude instead of at the north pole. To reproject the shapefile using rgdal, is it simply sufficient to enter the following proj4string as an argument (e.g. just change the value of +lat_0)?

e.g. 
spProj=spTransform(file,CRS("+proj=laea +lat_0=60 +lon_0=-100 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs"))

is this the proper way to chance the latitude of origin? or am I missing a step that is needed to create a custom CRS?

Thanks!

Julie





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