convBD2GCJ: Transform BD-09 (Baidu) coordinates to GCJ-02 (Google...

In madlogos/aseshms: Toolkit for ASES HMS Team

Description

GCJ-02 is coordinate system mandated by Chinese Gov't. BD-09 is Baidu specific coordinates that encrypts GCJ-02 further more. This function decrypts BD-09 back to GCJ-02 coordinates (Chinese coordinates).

Usage

convBD2GCJ(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

convBD2GCJ, convCoord.

Examples

## Not run: 
# Tiananmen square's BD-06 coordinate is c(39.91509, 116.40350)
# http://www.google.cn/maps/place/Tiananmen,+Dongcheng,+Beijing/@39.90875,116.39713,16z?hl=en

## Single point
convBD2GCJ(c(39.91509, 116.40350))  # or
convBD2GCJ(39.91509, 116.40350)  # get
#           lat       lng
# [1,] 39.90875  116.3971

## Multiple points
### Vectors
convBD2GCJ(c(39.91509, 116.40350), c(39.91509, 116.40350))  # get
#           lat       lng
# [1,] 39.90875  116.3971
# [2,] 39.90875  116.3971

### Matrix
m <- matrix(c(39.91509, 116.40350, 39.91509, 116.40350, 39.91509, 116.40350), nrow=2)
m
#           [,1]       [,2]       [,3]
# [1,]  39.91509   39.91509   39.91509
# [2,] 116.40350  116.40350  116.40350
convBD2GCJ(m)  # get
#           lat       lng
# [1,] 39.90875  116.3971
# [2,] 39.90875  116.3971
# [3,] 39.90875  116.3971

### data.frame
df <- data.frame(lat=c(39.91509, 39.91509, 39.91509, NA),
                 lon=c(116.40350, 116.40350, 116.40350, 116.40350))
convBD2GCJ(df)  # get
#           lat       lng
# [1,] 39.90875  116.3971
# [2,] 39.90875  116.3971
# [3,] 39.90875  116.3971
# [4,]       NA        NA

## End(Not run)

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