[Qgis-user] Announcing a work in progress on a flow mapping plugin : qFlowMapper

[Robin Cura]

Hello,

I've been working on a new plugin for some weeks, aiming to let people do
flow mapping within QGIS.
Eventhough the plugin is yet not releaseable due to many bugs and unfinished
features, I just wanted to announce it in case somebody
would be interrested in it or would be working on something similar.

Features (done and scheduled) :

_Creating simple lines from an origin/destination table + a point layer, or
from o/d + polygon layer. (this feature should be quite easy to do, but yet,
I didn't work on it, and it could be implemented in another plugin that
would only be used for those lines creations).

_ Creating and exporting Bezier curves within QGIS, through a global or
feature by feature manual editing. The aim of this feature is to let user
design Bezier curves within QGIS, without having to use a third party tool
like Inkscape or Adobe Illustrator. Considering geometries do not handle
arcs neither curves, the shapefiles will be segmented, but the SVG export is
a native Bezier
curve. I can't use the map composer for it, as it don't support Bezier path.
This feature half works : I can create automatically Bezier control points,
and edit them manually, and then,
convert all of the lines to Bezier. I've been designing a maptool object for
transparent manipulation, and work is still in progress in this domain.
The exported SVG should also be "importable" and editable in QGIS, so that
user can keep a track of their manipulations on a flow map.

_ Applying some algorithms to flows : Currently, I implemented an algorithm
named FDEB (Force-Directed Edge Bundling, see here :
www.win.tue.nl/~dholten/papers/forcebundles_eurovis.pdf<http://www.win.tue.nl/%7Edholten/papers/forcebundles_eurovis.pdf>
)
whose goal is to apply a bundling to lines, somehow similar to magnetic
fields attraction, in order to spot patterns and axes in dense flow maps.
Even if this is quite long to apply on medium/large shapefiles, it's working
the way it should :)
I'm considering the implementation of another algorithm for "spider" maps,
that can be found and explained here
:http://gis.stackexchange.com/questions/5204/curved-point-to-point-route-maps/5224#5224

A first, experimental, experimental version should be released within some
weeks, and then, I'll ask for your feedbacks :)

Until this, you can of course give me ideas/notices on what should be in the
plugin, and you can consult the sources here, keeping in consideration that
qFlowMapper is still under a lot of development :
https://github.com/RCura/PluginFlux

Thanks to the community for the help given so far,

Robin.
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