我有几个多边形&我喜欢从这些多边形内的几个栅格图层中提取平均值。 当我将这些添加到ArcMap时,我意识到两种数据类型的投影不匹配。我可以通过使用项目工具(数据管理工具箱>投影和转换工具集>栅格)来解决ArcGIS中显示的问题。所以,我试图通过将数据加载成R以下面的方式(该代码的一部分)以规范的投影:R中栅格和多边形的坐标参考系统
栅格:
for (i in 1:length(rasterlist1))
{ndvi_raster_stack1[i]<-raster(rasterlist1[i])
raster::NAvalue(ndvi_raster_stack1[[i]])<--999
projection(ndvi_raster_stack1[[i]])<-"+proj=utm +ellps=WGS84 +datum=WGS84 +units=m"}
> ndvi_raster_stack1[[1]]
class : RasterLayer
dimensions : 226, 150, 33900 (nrow, ncol, ncell)
resolution : 0.57504, 0.5753628 (x, y)
extent : -28.728, 57.528, -55.08, 74.952 (xmin, xmax, ymin, ymax)
coord. ref. : +proj=utm +ellps=WGS84 +datum=WGS84 +units=m +towgs84=0,0,0
values : Z:\master\lusmeg_sw_kernel_data\ndvi0910\Y2008_P47.tif
min value : -91
max value : 550.8125
多边形:
for (i in 1:length(poplist))
{pop_kernels[i]<-readShapeSpatial(poplist[i],repair=TRUE,proj4string=CRS("+proj=utm +ellps=WGS84 +datum=WGS84 +units=m"))
pop_kernels[[i]]<-unionSpatialPolygons(pop_kernels[[i]],ID=c(rep(1,times=length(pop_kernels[[i]])-1),0),threshold=NULL,avoidGEOS=FALSE)}
> str(pop_kernels[[1]])
Formal class 'SpatialPolygons' [package "sp"] with 4 slots
[email protected] polygons :List of 2
.. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
.. .. .. [email protected] Polygons :List of 2
.. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
.. .. .. .. .. .. [email protected] labpt : num [1:2] 2404422 893343
.. .. .. .. .. .. [email protected] area : num 1.15e+12
.. .. .. .. .. .. [email protected] hole : logi FALSE
.. .. .. .. .. .. [email protected] ringDir: int 1
.. .. .. .. .. .. [email protected] coords : num [1:1625, 1:2] 2551236 2533236 2533236 2523236 2523236 ...
.. .. .. .. .. .. .. ..- attr(*, "dimnames")=List of 2
.. .. .. .. .. .. .. .. ..$ : NULL
.. .. .. .. .. .. .. .. ..$ : chr [1:2] "x" "y"
.. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
.. .. .. .. .. .. [email protected] labpt : num [1:2] 2468549 865776
.. .. .. .. .. .. [email protected] area : num 6.31e+11
.. .. .. .. .. .. [email protected] hole : logi TRUE
.. .. .. .. .. .. [email protected] ringDir: int -1
.. .. .. .. .. .. [email protected] coords : num [1:1385, 1:2] 2551236 2551236 2563236 2563236 2569236 ...
.. .. .. .. .. .. .. ..- attr(*, "dimnames")=List of 2
.. .. .. .. .. .. .. .. ..$ : NULL
.. .. .. .. .. .. .. .. ..$ : chr [1:2] "x" "y"
.. .. .. [email protected] plotOrder: int [1:2] 1 2
.. .. .. [email protected] labpt : num [1:2] 2404422 893343
.. .. .. [email protected] ID : chr "0"
.. .. .. [email protected] area : num 1.15e+12
.. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
.. .. .. [email protected] Polygons :List of 1
.. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
.. .. .. .. .. .. [email protected] labpt : num [1:2] 2468549 865776
.. .. .. .. .. .. [email protected] area : num 6.31e+11
.. .. .. .. .. .. [email protected] hole : logi FALSE
.. .. .. .. .. .. [email protected] ringDir: int 1
.. .. .. .. .. .. [email protected] coords : num [1:1385, 1:2] 2551236 2541236 2541236 2529236 2529236 ...
.. .. .. .. .. .. .. ..- attr(*, "dimnames")=List of 2
.. .. .. .. .. .. .. .. ..$ : NULL
.. .. .. .. .. .. .. .. ..$ : chr [1:2] "x" "y"
.. .. .. [email protected] plotOrder: int 1
.. .. .. [email protected] labpt : num [1:2] 2468549 865776
.. .. .. [email protected] ID : chr "1"
.. .. .. [email protected] area : num 6.31e+11
[email protected] plotOrder : int [1:2] 1 2
[email protected] bbox : num [1:2, 1:2] 1819236 207017 3013236 1577017
.. ..- attr(*, "dimnames")=List of 2
.. .. ..$ : chr [1:2] "x" "y"
.. .. ..$ : chr [1:2] "min" "max"
[email protected] proj4string:Formal class 'CRS' [package "sp"] with 1 slots
.. .. [email protected] projargs: chr " +proj=utm +ellps=WGS84 +datum=WGS84 +units=m +towgs84=0,0,0"
我可以绘制多边形和栅格分开,但是当我尝试在栅格上绘制其中一个多边形时,多边形不会显示:
plot(ndvi_raster_stack1[[1]],xlab="Longitude",ylab="Latitude")
plot(pop_kernels[[1]],col="black",add=TRUE)
看来他们还是没有“重叠”。这也是由不同的边框表示,我认为:
> bbox(ndvi_raster_stack1[[1]])
min max
s1 -28.728 57.528
s2 -55.080 74.952
> bbox(pop_kernels[[1]])
min max
x 1819236 3013236
y 207017 1577017
因为我想多边形中提取栅格值,我必须确保他们以正确的方式引用。 有人有一个想法可能是什么问题?