小编te_*_*_ar的帖子

我有几个多边形,我喜欢从这些多边形中的几个栅格图层中提取平均值.当我将它们添加到ArcMap时,我意识到两种数据类型的投影不匹配.我可以使用"项目"工具("数据管理"工具箱>"投影和转换"工具集>"栅格")解决ArcGIS中显示的问题.所以我尝试通过以下方式将数据加载到R中来标准化投影(部分代码):

栅格数据:

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 …