Convert the HK80UTM coordinates to HK80GEO coordinates

HK80UTM_TO_HK80GEO(N, E, zone = c(49, 50))

Arguments

N	Numeric, Northern coordinate in meters.
E	Numeric, Eastern coordinate in meters.
zone	zone, UTM zone, either 49 or 50 for Hong Kong.

Details

This function uses equation 3, 4, 5 in the explanatory notes to convert the HK80UTM coordinates into HK80GEO coordinates (latitude and longitude) in decimal degrees. Mode details could be found at: Page C9 and C10 on the explanatory notes.

Value

latitude

latitude in decimal degrees

longitude

longitude in decimal degrees

References

Survey & Mapping Office Lands Department, Hong Kong Government (1995). Explanatory Notes on Geodetic Datums in Hong Kong, available at: http://www.geodetic.gov.hk/smo/gsi/data/pdf/explanatorynotes.pdf

Author

Jinlong Zhang

Note

The coordinates should be within the range of Hong Kong. Providing coordinates outside Hong Kong will lead to wrong results.

Examples

options(digits = 15)
HK80UTM_TO_HK80GEO(2483775, 208930, zone = 50)
#>          latitude        longitude
#> 1 22.435188997523 114.172349350774

#### $latitude
#### [1] 22.435188997523
#### 
#### $longitude
#### [1] 114.172349350774

##### Answer from the explanatory note:
### 22 + 26/60 + 06.89/3600 = 22.43524722
### 114 + 10/60 + 20.39/3600 = 114.1723306