[Qgis-developer] MapCanvasItem scaling

[Jorge Tornero]

Hello all,

I'm gathering some ideas to make a plugin (related to fishing gears and
positioning) which would show the position of a vessel and a towed gear.
I'm trying to make a, say so, pointer (like th eone in GPS plugin) or
marker for the ship and its gear.

Currently I've tested QgsMapCanvasItem and it is OK (I'm able to draw the
ship, rotate it depending on the bearing or update positions, for
instance), but I'm stuck with a simple thing: I can't figure out how to
plot it with the correct size depending on the map scale. I will know,
among other measures, the ship length and width in meters (or whatever real
world unit is used... feet, yards)

Of course, providing that the overall size of ship+gear can be in the range
of 1000 to 2000 meters, there is certain scales in with it's not worth to
draw, and it shouldn't be too complicated to implement a "scale switch".

Does anyone know articles/resources about how to cope with this?

Thank you very much for your time, have a nice weekend

Jorge Tornero
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