Goals

This project is intended for information about and discussion how different programming languages are used in OSG software and what's available.

A specific interest for this project is to discuss how to enhance or achieve interoperability between libraries and tools written in different languages.

Audience

The contents are inteded for

beginning developers who are looking for basic information and pointers,
more seasoned developers who may not be well informed what's happening among languages they are not using, and
educators, who teach GIS programming and software development.

Libraries

Geospatial software libraries provide the functionalities that belong to general categories of

Data management
Analysis
Visualization

In practical tools the specialized geospatial software have to be linked to general software libraries and toolkits like GUI toolkits, network software, etc.

Interoperability

Maintain functionally equivalent libraries in two languages (JTS/GEOS)
Use Swig (GDAL, GEOS, GRASS)
Use .Net/mono (MapWindow)

Using Swig

How to achieve a robust mapping between memory management in low level language and in the interface language?

The problem is that in low level language the programmer usually explicitly deletes an object (smart pointers are an exception) and in a scripting language the programmer usually doesn't. The binding should somehow make sure that all low level objects exist as long as they are needed but not longer. Different schemes exist in both worlds for managing this, but their interaction may make the problem even worse, especially when a single binding code (swig) should take care of it.

This problem exists for example in GDAL, where things like

band = gdal::Open('filename').GetRasterBand(0)

usually result in bad objects.

C, C++, Fortran and other "low-level" languages

Many fundamental libraries are written in these languages
These can be wrapped efficiently with Swig

Java

Java is a hybrid in the sense that it's used for fundamental libraries but it is also often preferred also for its high-level features (strong OO). Notable Java OSG include JTS, uDig, ...

Scripting languages

Scripting languages take the burden of memory management and compilation and linking off from the developer.

Perl

Geo modules in CPAN: http://cpan.org/modules/by-module/Geo/
Cartography modules in CPAN (there's only one): http://cpan.org/modules/by-module/Cartography/
Geography modules in CPAN: http://cpan.org/modules/by-module/Geography
Tree::R module in CPAN: http://cpan.org/modules/by-module/Tree/
GDAL/OGR has Swig-based Perl interfaces
GRASS has prototype Swig-based Perl interfaces
Discussion about gdal, ogr, some Geo, and Gtk2::Ex::Geo modules: http://map.hut.fi/PerlForGeoinformatics/
Geo-Perl email list: https://list.hut.fi/mailman/listinfo/geo-perl
FreeGIS database on Perl: http://freegis.org/database/?cat=24

todo:

Perl bindings for GEOS

PHP

PHP stands for "PHP: Hypertext Preprocessor" and is a widely-used Open Source general-purpose scripting language that is especially suited for Web development and can be embedded into HTML. Its syntax draws upon C, Java, and Perl, and is easy to learn. The main goal of the language is to allow web developers to write dynamically generated webpages quickly, but you can do much more with PHP. (from the PHP manual preface)

CartoWeb: http://cartoweb.org/
Chameleon: http://chameleon.maptools.org/index.phtml
Mapbender: http://www.mapbender.org
ka-map: http://ka-map.maptools.org/
PHP/MapScript (UMN MapServer): http://mapserver.gis.umn.edu/docs/reference/phpmapscript-class/class-intro/
kvwmap: http://kvwmap.sourceforge.net/

Python

Python Cartographic Library: http://zcologia.org/cartography

R

R is a language for statistical computing.

R spatial: http://r-spatial.sourceforge.net/

Ruby

FreeGIS database on Ruby: http://freegis.org/database/?cat=63

Programming Languages Project

Contents