Wednesday, April 17, 2013

SVG - Coordinate Systems

Most ProjectedCRS (Map Projection) have the north direction represented by positive values of the second axis and conversely SVG has a y-down coordinate system

That's why, in order to follow the usual way to represent a map with the north at its top. 
It is recommended for that kind of ProjectedCRS to use the ‘svg:transform’ global attribute with a 'scale(1, -1)'

Most Geographic2dCRS have the latitude as their first axis rather than the longitude, which means that the south-north axis would be represented by the x-axis in SVG instead of the usual y-axis 

it is recommended for that kind of Geographic2dCRS to use the ‘svg:transform’ global attribute with a 'rotate(-90)' value as in the first example (while also adding the 'scale(1, -1)' as for ProjectedCRS). 
3:55 PMtech-mashup