Before (some) spatial analysis, we need to make sure the coordinate reference systems of the layers are the same. I am doing
intersect with two layers. I did that under a coordinate before. If I change the coordinate, will the result also be changed?
r language for GIS analysis, especially the package
Before spatial analysis, I first define the CRS used for the data analysis flow.
my_crs <- 6668 # 6668 is the EPSG id of the geographical coordinate system JGD 2011 # which is basically the same as WGS 84
Then I have two
sf data, one is point data (which is about 10000 points), and another one is polygon data. Let's say their names are "my_point" and "my_polygon". Then I want to get the points intersecting with the polygon, so:
my_inter <- st_intersection(my_point, my_polygon)
I wonder if I change the
my_crs into another one, for example,
my_crs <- 6676 (6676 is a projected coordinate reference system), then I do
my_inter <- st_intersection(my_point, my_polygon). I found the results changed a little bit. I wonder why is that.