Version 2 (modified by jdunck, 7 years ago) (diff)

Clarified references to background info


GeoDjango Background

The content herein is a loosely structured collection of notes and links that we have found useful, not necessarily what will be supported in the future. Feel free to add in your own notes, links, and comments.

What's GIS?

  • Series 1, 2, 3, 4, 5, 6 of blog posts by Charles Savage giving intro to GIS; choice quote from an early post: "If you feel like ending a conversation with a developer then simply bring up the topic of character encodings ... [o]r ... coordinate systems. ... So in the spirit of Tim Bray's and Joel Spolsky's wonderful writeups of character encodings, I thought I'd put together a basic survival guide to coordinate systems over my next few posts and then tie it back to Google Maps."
  • More on map projections, including why people can't agree on just one (utf-8).
  • geodesy the field of science for this stuff.

Useful Code

  • PostGIS, the OpenGIS SQL Types (pdf) implementation for Postgresql
  • GEOS, low-level C++ port of Jave Topology Suite, used by PostGIS
  • GeoTypes is a type (and conversion) library for PostGIS via psycopg.
  • Geopy
    • Calculates distances using (very accurate) Vincenty, and uses the WGS 84 datum by default.
    • Has utility functions for unit of measurement (UOM) conversions (e.g. meters -> kilometers, kilometers -> miles, etc.)
    • Excellent GeoCoding capabilites. Has interfaces for Google, Yahoo, Microsoft Live, MediaWiki, and
  • GDAL/OGR, a library for fiddling with raster geo images.
    • Has a Python interface. A SWIG interface is in development, but not yet stable (no access to full API).
    • shapelib and ogr2ogr are useful for ESRI shapefile manipulations. ESRI shapefiles are a lingua frana GIS format.
  • Geo::Coder::US An excellent Perl library for GeoCoding that powers Users can create their own Geographic databases using the Census Bureau's TIGER/Line data (see below).
  • GeoRosetta, CC-BY-SA licensed, quality-controlled, collection of geocoding data. Not yet released to public(?).
  • MapServer: University of Minnesota (UMN) "open source development environment for building spatially-enabled internet applications."
  • Mapnik: C++ and Python toolkit for developing mapping applications. Claimed benefits over MapServer: "It uses the AGG library and offers world class anti-aliasing rendering with subpixel accuracy for geographic data. It is written from scratch in modern C++ and doesn't suffer from design decisions made a decade ago." See MapNik FAQ.
  • pyproj: Pyrex generated python interface to PROJ.4 library.
  • Ruby on Rails
    • GeoRuby: Interface for PostGIS and MySQL spatial extensions, but not sure about spatial querying.
    • IvyGIS: Google-maps type displays with RoR and UMN's MapServer
    • Spatial Adapter for Rails: A plugin for Rails which manages the MySql Spatial and PostGIS geometric columns in a transparent way (that is like the other base data type columns). This might have some useful techniques for when we try to support other spatial extensions other than PostGIS.
    • Cartographer GMaps plugin

Useful Data

  • TIGER/Line: "The TIGER/Line files are extracts of selected geographic and cartographic information from the Census Bureau's TIGER® (Topologically Integrated Geographic Encoding and Referencing) database." This data is useful in creating your own geocoding database service. Currently 2006 Second Edition is the latest. Note: The Census Bureau will be providing SHP files in Fall, 2007.
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