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I have ~40 points in UTM zone 19 taken from Peru that I would like to convert to lat/long to project onto Google Earth. I am having some problems with PBSmapping and can't seem to figure out the solution. I have searched through the forums and tried several different methods, including the project command in proj4 but still can't get this to work. Here is the code I have currently written

library(PBSmapping)
#just two example UTM coordinates
data<-as.data.frame(matrix(c(214012,197036,8545520,8567292),nrow=2))
attr(data,"projection") <- "UTM"
attr(data, "zone") <- 19
colnames(data)<-c("X","Y")
convUL(data,km=FALSE)

The corresponding lat/longs should be somewhere with lats between -12.9XXXXX and -13.0XXXXX and long between -71.8XXXX to -71.4XXXX. The values given by convUL seem to be way off.

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1 回答 1

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一旦你得到有效的坐标对，你可以做这样的事情：

library(rgdal)
data <- data.frame(id = c(1:2), x = c(214012,197036) , y = c(8545520,8567292))
coordinates(data) = ~x+y

分配投影

# Use the appropriate EPSG Code
proj4string(data) = CRS('+init=epsg:24891') # 24891 or 24893

转换为地理坐标 enter code heredata_wgs84 <- spTransform(data, CRS('+init=epsg:4326'))

获取一些有效的背景数据来绘制它

# Country data
package(dismo)
peru <-getData('GADM', country='PER', level=0)
plot(peru, axes = T)
plot(data, add = T)

编写您的 KML 文件

# Export kml
tmpd <- 'D:\\'
writeOGR(data_wgs84, paste(tmpd, "peru_data.kml", sep="/"), 'id', driver="KML")
于 2013-04-19T22:06:34.673 回答