convertbng 0.2.5

Fast lon, lat to BNG conversion

Fast longitude, latitude to BNG conversion, and vice versa, using a multithreaded Rust binary and FFI.

This module provides two methods:

util.convertbng(lons, lats) – pass sequences (such as lists or numpy arrays) of Longitudes andLatitudes, or single values of each. Returns a list of two lists containing Easting and Northing integers (longs), respectively.

util.convertlonlat(eastings, northings) – pass sequences (such as lists or numpy arrays) of Eastings, Northings, or single values of each. Returns a list of two lists containing Longitude and Latitude floats, respectively

NOTE: Coordinate pairs outside the BNG bounding box will return a result of [[9999], [9999]], which cannot be mapped. Since transformed coordinates are guaranteed to be returned in the same order as the input, it is trivial to check for this value. Alternatively, ensure your data fall within the bounding box before transforming them:

Latitude:

East: 1.768960 (Max)

West: -6.379880 (Min)

Longitude:

North: 55.811741 (Max)

South: 49.871159 (Min)

Installation

Installation as a binary wheel using pip, for OS X:

pip install convertbng

Binary wheels aren’t yet available for Linux or Windows, but installation directly from Github works:

pip install git+git://github.com/urschrei/convertbng.git

Usage

from convertbng.util import convertbng, convertlonlat

# convert a single value
res = convertbng(lon, lat)

# convert lists of longitude and latitude values to BNG Eastings and Northings
lons = [lon1, lon2, lon3]
lats = [lat1, lat2, lat3]
res_list = convertbng(lons, lats)

# convert lists of BNG Eastings and Northings to longitude, latitude
eastings = [easting1, easting2, easting3]
northings = [northing1, northing2, northing3]
res_list_en = convertlonlat(eastings, northings)

# assumes numpy imported as np
lons_np = np.array(lons)
lats_np = np.array(lats)
res_list_np = convertbng(lons_np, lats_np)

Testing

Run nosetests (requires Nose)