Convert Lambert conformal conic projection to wgs8

2019-07-18 10:23发布

问题:

I have Lambert conformal conic projection x,y information.
I need the WGS84 coordinate. But I don't know what is lcc exactly.
I have provided the lcc information below.
Is there a way to convert lcc to WGS84 in r?

example lcc x,y : xy <- cbind(c(509535.7, 514535.7),c(201098.6, 201098.6)) 

lcc information :
Latitude of first standard parallel : 30.0
Latitude of second standard parallel : 60.0
Origin latitude : 38.0 Origin longitude : 126.0
Easting of computation point : 43
Northing of computation point : 136
4 edge lon,lat point : left-upper(43.3935, 123.3102), left-lower(31.7944, 123.7613),
right-upper(43.2175, 132.7750), right-lower(31.6518, 131.6423)

回答1:

What you are asking for is really not possible because Lambert conformal conic is a map projection while WGS84 is a datum. It may well be that your LCC data already are relative to the WGS84. I assume you want to transform LCC to longitude/latitude. (And I am also assuming that your input data is WGS84.)

xy <- cbind(c(509535.7, 514535.7),c(201098.6, 201098.6)) 

library(sp)
library(rgdal)
crs <- CRS("+proj=lcc +lat_1=30 +lat_2=60 +lat_0=38 +lon_0=126 +datum=WGS84")
p <- SpatialPoints(xy, proj4string=crs)
g <- spTransform(p, CRS("+proj=longlat +datum=WGS84"))
coordinates(g)

For raster data (since you list 'raster' as a keyword), see raster::projectRaster