cl-geo

Overview

cl-geo is a set of geographic data structures and operations. Though it's not a full GIS system, it's a simple set of tools for GIS applications.

cl-geo is used by the En Route public transit trip planner, which powers En Route Spokane.

Warning

cl-geo is deprecated. The author does not anticpate enhancing this library very much in the future, because the amount of work required is non-trivial and other techniques are being used in place of this library to solve the same problems. (Particularly, En Route now relies on PostGIS for much of its geospatial heavy lifting.)

This library has known accuracy problems due to improper mathematical technique. These methods are not expected to be accurate:

Additionally, the AREA function on POLYGONs was so bad in practice that it had to be removed from 0.2.

Quick reference

(The following descriptions are intended for quick reference and feature overview. See the documentation embedded in the classes and functions for more detail.)

Data structures

Functions

Generic functions apply to many combinations of different data structures, and include:

Bearing (direction) calculations are included:

Other functions include:

Download

The most recent release is 0.2, released 2011-06-14. It depends on: spatial-trees (Debian: cl-spatial-trees), cl-jpl-util (version 0.4 or later).

Breaking changes in 0.2:

Other changes:

Download:

Older version:

I sign all my software with OpenPGP, key ID 0x80555CED7394F948, fingerprint 2771 AF53 5D09 BDFB A8D0 BEF3 8055 5CED 7394 F948.

Copying

This software is licensed under permissive, BSD-like terms, copied from the ISC license:

Copyright (c) 2009, Jean-Paul Guy Larocque

Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Contact

I'm reachable via e-mail for feedback, questions, help requests, and bug reports: jpl-software at surejourney.com

— J.P. Larocque