> Am 04.06.2020 um 12:31 schrieb Serge Stinckwich <serge.stinckw...@gmail.com>: > > > > On Thu, Jun 4, 2020 at 4:11 PM Norbert Hartl <norb...@hartl.name > <mailto:norb...@hartl.name>> wrote: > 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: > > > Thank you Norbert for your interest on that topic. > I put Etienne Delay because he is not ont the pharo-users mailing-list and > I'm working with him on GIS issues for CORMAS. > > - 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 > > > You have done a lot of work. And we add all the work done by Hernan on > supporting ESRI shapefiles, we have already a good start. > > Etienne also mention the OpenGIS model in this issue: > https://github.com/cormas/cormas/issues/139 > <https://github.com/cormas/cormas/issues/139> > > From what I understood, OpenGIS model crosscut many points of the Geography > package: > http://portal.opengeospatial.org/files/?artifact_id=25355 > <http://portal.opengeospatial.org/files/?artifact_id=25355> > > 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. > > We can try to do an online meeting to discuss about that with Etienne and > other people interested by this topic. > We are mostly interested to have GIS support on CORMAS, so having a common > repository will definitively help us. > At the moment we are using Roassal2 for CORMAS visualisatin and we are moving > towards Roassal3.
Good idea! I just created the Geography package because I felt the need for it. But if there is something better I would like to use this instead. I'm generally available the best at wednesdays and thursdays. Next week is already stuffed but if you propose some DateAndTimes I'm sure we find a match. Which timezone are you in at the moment? Norbert > Regards, > -- > Serge Stinckwich > https://twitter.com/SergeStinckwich <https://twitter.com/SergeStinckwich>
