timothygu / utm

Bidirectional UTM-WGS84 converter for JavaScript.

utm

Bidirectional UTM-WGS84 converter for JavaScript.

Translated directly from Tobias Bieniek's implementation in Python.

Usage

var utm = require('utm')

utm.toLatLon(easting, northing, zoneNum, zoneLetter, northern, strict = true)

Convert from UTM-WGS84 to latitude/longitude coordinates. One and only one of zoneLetter and northern must be specified. strict option specifies whether easting and northing are checked against their respective ranges.

Returns { latitude, longitude }.

utm.fromLatLon(latitude, longitude[, zoneNum])

Convert from latitude/longitude coordinates to UTM-WGS84. zoneNum can be set to force a specific zone number.

Returns { easting, northing, zoneNum, zoneLetter }.

utm's Issues

Northern never gets set

A bug in the code prevents northern from being set

Invalid zoneNum for longitude = 180

Appears it's been 5 years or so since this code was last touched. In the case it's still being maintained...

• latLonToZone() returns either zone 1 and 61 for longitudes -180 and 180, respectively. It should return zone 1 for both values.
• the easting returned from fromLatLong() depends on the current behavior of latLonToZone(); fixing the latter breaks the former.

Thanks ;)

utm.toLatLon: unable to use "northern" without "zoneLetter" (undefined is not false)

To reproduce:

– call utm.toLatLon(easting, northing, 55, undefined, false) and you get
– "Error: either zone_letter or northern needs to be set"

This is despite the fact that northern in fact is set, but to false. The error seems to be caused by an incorrect translation from Python's if not zone_letter and northern is None: my understanding is that we must check to see if northern is undefined.