[Gambas-user] Coordinate system in Gambas Graphics

[Jesus Guardon]

Doriano Blengino wrote:
> 
> simple linear transformation is possible by using draw.translate() and 
> draw.scale(); draw.reset() will reset the transformation matrix. 
> Draw.push() and draw.pop() exist to save and restore the matrix.
> 
> I think this is enough to map simple world 2D coordinates; it is 
> effective and scales everything but text.
> 
> For more complicated things, they should be implemented in software.
> 
> Regards,
> Doriano Blengino
> 

Hi all

Well, I'm totally lost with this subject. What I'm trying to do is to map
the real world coordinates into a picture of a geographical map of Europe,
for plotting parallels, meridians and some other stuff.

Lets say we have a picture of Europe 800x600px and its real coordinates are:
72N  -25W (upper left corner) and -18S  44E (bottom right corner). How do I
translate pixels to coordinates to draw on the map directly using real
coordinates?
I don't understand very well what matrices are, and how to apply with Gambas
syntax.
Any example or explanation on how to accomplish this project are welcome.

This is what I did so far in VB.net, but this is another history...  :-) 
(in Spanish):  http://ea7dfh.es/MapLoc/

Thanks,

Jesus

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