problem180meridian 0.1.0

Fixes 180 degree crossing issue for vector geodata

problem180meridian

Python module to fix 180 degree crossing issue for vector geodata

Take care of topology errors on the 180th meridian

Having vector geodata with lines/polygons crossing 180th meridian, their geometry is likely to be displayed wrongly in geographic CRS like EPSG:4326. This module helps to modify the original Polygon or Multipolygon geometry to be correctly represented in a geographic CRS.

Install

The module is available from PyPi, one may install it using pip:

pip install problem180meridian

To use it from Python console one may use:

import problem180meridian

Usage

The module contains the following functions:

check180(coordinates) - checks if any segment in a pair of coordinates crosses 180th meridian and returns a tuple of two values. The first one is False if no crossing was found, and True if at least one was found. Without any crossing, the second value is None, otherwise it's an array of bool values where True marks the 180th meridian crossing and False means no crossing.

cross180(coord1, coord2, lon_buffer=0.0) - takes a pair of point coordinates a line between which is supposed to cross the 180th meridian and returns a pair of point coordinates on the crossing between this line and the meridian, or at a distance from it equal to lon_buffer parameter (in longitude degrees).

split180_multipolygon(coordinates, lon_buffer=0.0) - takes coordinates as input and returns new ogr.Geometry object as Multipolygon.

Development

Plans for the module development:

• direct processing of wkt and ogr.Geometry input
• processing line geometry as well as polygons
• revert algorithm to unite geometry separated by the 180th meridian for correct representation in projected CRS, like UTM

Author

Made by Sergei Sadkov (@sergsadkov)