convGCJ2WGS: Transform GCJ-02 (Google CN/Amap) coordinates to WGS-84...

In madlogos/recharts2: An R Interface to ECharts3

Description

GCJ-02 is coordinate system mandated by Chinese Gov't. This function decrypts it back to WGS-84 coordinates (gloabal coordinates).

Usage

convGCJ2WGS(y, ...)

Arguments

y	A vector c(latitude, longitude) simply latitude a matrix (row 1-2 or col 1-2). The function will choose how to read the data a data.frame (col 1-2)
...	When y is only latitude, you can pass in x (longitude) here. when y is a vector of c(lat, lon), you can pass in the rest vectors as well. when y is a matrix or a data.frame, ... is omitted.

Value

A 2-col data.frame ([lng, lat]) of transformed coordinates.

Note

Latitude is the horizontal line serving as y-axis metric, longitude is the vertical line serving as x-axis metric.

Author(s)

Yiying Wang, [e-mail]

References

https://on4wp7.codeplex.com/SourceControl/changeset/view/21483#353936

See Also

convWGS2GCJ, convCoord.

Examples

## Not run: 
# Tiananmen square's GCJ-02 coordinate is c(39.908746, 116.397131)
# http://www.openstreetmap.org/#map=19/39.90734/116.39089

## Single point
convGCJ2WGS(c(39.908746, 116.397131))  # or
convGCJ2WGS(39.908746, 116.397131)  # get
#           lat      lng
# [1,] 39.90734 116.3909

## Multiple points
### Vectors
convGCJ2WGS(c(39.908746, 116.397131), c(39.908746, 116.397131))  # get
#           lat      lng
# [1,] 39.90734 116.3909
# [2,] 39.90734 116.3909

### Matrix
m <- matrix(c(39.908746, 116.397131, 39.908746, 116.397131, 39.908746, 116.397131), nrow=2)
m
#           [,1]      [,2]      [,3]
# [1,]  39.90875  39.90875  39.90875
# [2,] 116.39713 116.39713 116.39713
convGCJ2WGS(m)  # get
#           lat      lng
# [1,] 39.90734 116.3909
# [2,] 39.90734 116.3909
# [3,] 39.90734 116.3909

### data.frame
df <- data.frame(lat=c(39.908746, 39.908746, 39.908746, NA),
                 lon=c(116.397131, 116.397131, 116.397131, 116.397131))
convGCJ2WGS(df)  # get
#           lat      lng
# [1,] 39.90734 116.3909
# [2,] 39.90734 116.3909
# [3,] 39.90734 116.3909
# [4,]       NA       NA

## End(Not run)

madlogos/recharts2 documentation built on May 21, 2019, 11:03 a.m.