I started this initiative for our company because we are in the mobility bubsiness where maps and geo centric things are important. It is not elaborate as a real GIS support but a start. So here my secret plan:
- GeoJSON [1] was done because web services came up with that format to exchange geo shape information. Furthermore database like MongoDB changed their internal support for 2d/2dsphere indexes also to GeoJSON. There is a package GeoJSON-Voyage which is start of a helper to easily store Geo data in voyage-mongo. - I started to do a KML Reader [2] because besides GeoJSON that is a widely used format. And this can be used in Google Earth which is the best free Geo editor that I know. - As KML and GeoJSON use a similar model for representing geo shapes and POIs I started to factor out that into the Geography package [3]. - At the moment in the Geography package there is only a 2D point class GGPoint to have something to hold geo coordinates (there is also a 3D variant). In the past I used Point as the class for these things but came to the conclusion that there is a distinction between a point and geo point when it comes to things like distance etc. So it is better to have them separate. Into this model I want to morph the classes for LineStrings, LinearRings, Polygons etc. from GeoJSON and KML to have a common foundation for the basic geo shapes lines, multi-lines, closed multi-lines (=polygons) etc. - As GGPoint is distinct to Point this is just the context where you use it. The Geography package should be a companion to the Geometry package [4] which I forked from TelescopeSt to make it a community package which is good for this plan but also for roassal which uses the Geometry package. To me the geoX model should be switched between Geometry and Geography regarding to the context you want to work in being planar or spherical. - In my tools that I build this model classes have also gt-inspector extension so the shapes can be viewed just by inspecting them. I'm fighting with the roassal team to make it possible for geo coordinates which conflicts at the moment with their defined thresholds. But with the factoring the shapes into Geography I will move those extension to the Geography package as well - I also implemented a polygon intersection algorithm (Weiler and Atherton) which I will then incorporate in any of the GeoX packages So these are the pieces that are there. The plan in text is: - Have a incarnation of a "point" and make that switch context from planar to spherical - Use planar treatment with the Geometry package (intersections etc.) - Use this "point" to generate shapes either geometric or geographic - Be able to read and write in common formats like GeoJSON and KML - Make shapes be composable and inspectable with the existing tools I think GIS needs more but what we have is more than just a start. The projection system with the current code is WGS84 for sure. If there are other needs we need to think about this early. For everything else I'm open ears. Even for the idea of having a pharo-gis github project to collect those things to a common place. But I like to discuss GIS and not if it makes sense to have a all of these github repos. Norbert [1] https://github.com/zweidenker/GeoJSON <https://github.com/zweidenker/GeoJSON> [2] https://github.com/zweidenker/KML <https://github.com/zweidenker/KML> [3] https://github.com/zweidenker/Geography <https://github.com/zweidenker/Geography> [4] https://github.com/pharo-contributions/Geometry <https://github.com/pharo-contributions/Geometry> > Am 04.06.2020 um 05:31 schrieb Serge Stinckwich <serge.stinckw...@gmail.com>: > > Dear all, > > there was already some discussion in the list about GIS support for Pharo > previously. > > Working on CORMAS multi-agent simulation platform: > https://github.com/cormas/cormas <https://github.com/cormas/cormas> some > developers feel the need to have more GIS support for Pharo. > > I know of existing GIS software: > - GeoJSON by Zweidenker: https://github.com/zweidenker/GeoJSON > <https://github.com/zweidenker/GeoJSON> > - ESRI ascii raster, done by Stephane recently: > https://github.com/Ducasse/ESRI-ASCII-Raster > <https://github.com/Ducasse/ESRI-ASCII-Raster> > - shapefile support by Hernan: http://smalltalkhub.com/#!/~hernan/Shapes > <http://smalltalkhub.com/#!/~hernan/Shapes> > (to be moved to github) > - I found this project also: http://www.squeaksource.com/gekon.html > <http://www.squeaksource.com/gekon.html> > > I know that Etienne Delay is also interested by GIS support and propose to > implement OpenGIS model support: https://github.com/cormas/cormas/issues/139 > <https://github.com/cormas/cormas/issues/139> > > Can we try to unite and maybe create a pharo-GIS organization on github to > federate our efforts? > > Cheers, > -- > Serge Stinckwich > https://twitter.com/SergeStinckwich <https://twitter.com/SergeStinckwich>
