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I load a shape file using R
maptools
package
Subcat<-readShapeSpatial("Contour500/Catchments500.shp",proj4string = CRS('+init=epsg:4326'))
class(Subcat)
[1] "SpatialPolygonsDataFrame"
attr(,"package")
[1] "sp"
Then I load another shape file
load("Temperature/WCAdj.RData")
class(WcT$Geoloc)
[1] "SpatialPoints"
attr(,"package")
[1] "sp"
I want to use the over function from sp package
over(WcT$Geoloc,Subcat)
But when I run it I get the next error
Error: identicalCRS(x, y) is not TRUE
This is strange as I used the same CRS for both files CRS('+init=epsg:4326'). I double checked and found a slight difference in the order of the attributes of the CRS
proj4string(Subcat)
[1] "+init=epsg:4326 +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0"
proj4string(WcT$Geoloc)
[1] "+init=epsg:4326 +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0"
The only difference is the order of the Attributes (+ellps, +no_defs and +datum), but all values are the same. I solved this by loading again Subcat using
Subcat<-readShapeSpatial("Contour500/Catchments500.shp",proj4string = CRS("+init=epsg:4326 +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0"))
However I wanted to know if there is another solution as I want to avoid the same error in the future and wanted to know where this error comes from. I checked the details of the CRS definition in (https://www.nceas.ucsb.edu/~frazier/RSpatialGuides/OverviewCoordinateReferenceSystems.pdf ) and in the SP package documentation https://cran.r-project.org/web/packages/sp/sp.pdf , but they do not give too many details regarding the order of the attributes.
Has anyone had the same issue?
Does anyone know how to avoid this?
Just in case
sessionInfo()
R version 3.3.3 (2017-03-06)
other attached packages:
[1] rgeos_0.3-2 maptools_0.8-27 rgdal_0.8-11 sp_1.0-14
Thanks in advance!
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