R 将 x 或 y 坐标分配给栅格单元以执行计算 [英] R Assigning x or y coordinate to cells of a raster to perform calculations

问题描述

是否有任何解决方案可以使用 R 将 X 或 Y 坐标分配给光栅图像的所有单元格?

Is there any solution to assign to assign X or Y coordinate to all of the cells of a raster image using R?

例如，假设我有一个包含 3x3 像元的栅格.左下坐标为 X=7,Y=15(米)，X 和 Y 方向的分辨率均为 +10 m(X 向右增加，Y 向上).然后，我想生成每个单元格都有 X 和 Y 值的栅格表面，如下所示:

For example, suppose I have a raster with 3x3 cells. The lower left coordinate is X=7,Y=15 (in meters), and resolution is +10 m for both, X and Y direction (X increases rightward, and Y upward). Then, I would like to generate raster surfaces where each cell has the X and Y value, like these ones:

X raster
7  17  27
7  17  27
7  17  27

Y surface
35  35  35
25  25  25
15  15  15

更新:这个是实际的光栅对象.

UPDATE: this is the actual raster object.

有没有办法做到这一点?

Is there any way to do this?

我尝试了包光栅"，但找不到解决方案.

I tried the package 'raster', but couldn't find a solution.

任何帮助将不胜感激.

推荐答案

这是我找到的解决方案，灵感来自@Carl 提交的评论.

This is the solution that I found, inspired in the comment submitted by @Carl.

假设我的栅格名为 d，具有以下特征:

Suppose my raster is called d, with these characteristics:

class       : RasterLayer
dimensions  : 59, 67, 3953  (nrow, ncol, ncell)
resolution  : 90, 90  (x, y)
extent      : 482855.6, 488885.6, 4763517, 4768827  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=tmerc +lat_0=0 +lon_0=-3 +k=1 +x_0=500000 +y_0=0 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0
data source : in memory
names       : subset
values      : 328, 1120  (min, max)

我首先用 x 坐标值生成了一个矩阵:

I first generated a matrix with the x coordinates values:

xm<-matrix(xFromCell(d,c(1:3953)),nrow=59,byrow=TRUE)

然后用矩阵创建一个栅格:

Then created a raster with the matrix:

x<-raster(xm,xmn=482855.6, xmx=488885.6,ymn=4763517,ymx=4768827)

最后，分配其投影:

projection(x)<-"+proj=tmerc +lat_0=0 +lon_0=-3 +k=1 +x_0=500000 +y_0=0 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0"

我还显示了光栅，看看结果是否正常...

I also displayed the raster, to see if results where OK...

plot(x)

...并阅读光栅描述

x
class       : RasterLayer
dimensions  : 59, 67, 3953  (nrow, ncol, ncell)
resolution  : 90, 90  (x, y)
extent      : 482855.6, 488885.6, 4763517, 4768827  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=tmerc +lat_0=0 +lon_0=-3 +k=1 +x_0=500000 +y_0=0 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0
data source : in memory
names       : layer
values      : 482900.6, 488840.6  (min, max)

我重复了这些步骤，但在第一步中使用了 yFromCell.

I repeated these steps, but using yFromCell in the first step.

这篇关于R 将 x 或 y 坐标分配给栅格单元以执行计算的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！