将纬度/经度转换为州平面坐标

Question

我有一个纬度和经度的数据集,我想转换为伊利诺斯东部的州平面坐标,使用EPSG 2790(http://spatialreference.org/ref/epsg/2790/)或者ESRI 102672(http://spatialreference.org/ref/esri/102672/).

这肯定在之前被问过; 我的代码基于这里的答案(rgdal R包中的spTransform中的"非有限变换检测"和http://r-sig-geo.2731867.n2.nabble.com/Converting-State-Plane-Coordinates-td5457204. HTML).

但由于某种原因,我不能让它工作:

library(rgdal)
library(sp)
data = data.frame(long=c(41.20,40.05), lat=c(-86.14,-88.15))
coordinates(data) <- ~ long + lat
proj4string(data) <- CRS("+init=epsg:4326") # latitude/longitude
data.proj <- spTransform(data, CRS("+init=epsg:2790")) # illinois east

得到:

non finite transformation detected:
  long    lat               
 41.20 -86.14    Inf    Inf 
Error in spTransform(data, CRS("+init=epsg:2790")) : failure in points 1
In addition: Warning message:
In spTransform(data, CRS("+init=epsg:2790")) :
  2 projected point(s) not finite

Answer 1

下面是一些更多的工作代码，可以阐明正在发生的事情：

# convert a state-plane coordinate to lat/long
data = data.frame(x=400000,y=0)
coordinates(data) <- ~ x+y
proj4string(data) <- CRS("+init=epsg:2804")
latlong = data.frame(spTransform(data, CRS("+init=epsg:4326")))
setnames(latlong,c("long","lat"))
latlong

给出：

  long      lat
 1  -77 37.66667

和：

# convert a lat/long to state-plane
data = latlong
coordinates(data) <- ~ long+lat
proj4string(data) <- CRS("+init=epsg:4326")
xy = data.frame(spTransform(data, CRS("+init=epsg:2804")))
setnames(xy,c("y","x"))
xy

给出：

> xy
      y             x
1 4e+05 -2.690839e-08

这是一个函数：

# this is for Maryland
lat_long_to_xy = function(lat,long) {
  library(rgdal)
  library(sp)
  data = data.frame(long=long, lat=lat)
  coordinates(data) <- ~ long+lat
  proj4string(data) <- CRS("+init=epsg:4326")
  xy = data.frame(spTransform(data, CRS("+init=epsg:2804")))
  setnames(xy,c("y","x"))
  return(xy[,c("x","y")])
}

Answer 2

当您为数据设置 时coordinates，必须在经度之前设置纬度。

换句话说，改变：

coordinates(data) <- ~ long + lat

到

coordinates(data) <- ~ lat+long

它应该有效。

library(rgdal)
library(sp)
data = data.frame(long=c(41.20,40.05), lat=c(-86.14,-88.15))
coordinates(data) <- ~ lat+long
proj4string(data) <- CRS("+init=epsg:4326")
data.proj <- spTransform(data, CRS("+init=epsg:2790"))
data.proj

给了我这个输出：

SpatialPoints:
          lat     long
[1,] 483979.0 505572.6
[2,] 315643.7 375568.0
Coordinate Reference System (CRS) arguments: +init=epsg:2790 +proj=tmerc
+lat_0=36.66666666666666 +lon_0=-88.33333333333333 +k=0.9999749999999999 +x_0=300000
+y_0=0 +ellps=GRS80 +units=m +no_defs