创建LAT -90到90和-180到90的网格

Question

我想创建一个网格，我用它：

reso = 0.25
xs <- seq(-180, 180, by=reso)
ys <- seq(-90, 90, by=reso)
grd <- expand.grid(
  x=xs,
  y=ys,
  presence=0
)
head(grd)

这给了我这个，

    x   y presence
1 -180.00 -90        0
2 -179.75 -90        0
3 -179.50 -90        0
4 -179.25 -90        0
5 -179.00 -90        0
6 -178.75 -90        0

但是，我想要这个，

x             y        presence
-179.875    -89.875     0
-179.875    -89.625     0
-179.875    -89.375     0
-179.875    -89.125     0
-179.875    -88.875     0
-179.875    -88.625     0
-179.875    -88.375     0
-179.875    -88.125     0
-179.875    -87.875     0
-179.875    -87.625     0
-179.875    -87.375     0
-179.875    -87.125     0
-179.875    -86.875     0
-179.875    -86.625     0
-179.875    -86.375     0

Please note how the x and y increases.

Answer 1

reso <- 0.25
xs <- seq(-179.875, 179.875, reso)
ys <- seq(-89.875, 89.875, reso)
grd <- expand.grid(y=ys, x=xs, presence=0)
grd <- grd[,c(2,1,3)]
head(grd)
#          x       y presence
# 1 -179.875 -89.875        0
# 2 -179.875 -89.625        0
# 3 -179.875 -89.375        0
# 4 -179.875 -89.125        0
# 5 -179.875 -88.875        0
# 6 -179.875 -88.625        0