[OpenLayers-Users] createRegularPolygon 'circle' radius units?
Phil Scadden
p.scadden at gns.cri.nz
Thu Sep 6 14:50:12 PDT 2012
I would note that the circle is 1600 wide (as expected) but the scale
distance between roads ~ 2500m. You are running foul of the fact
mercator a terrible projection for this kind of use. ie the ratio of map
distance to true distance gets large as you move towards the poles. On a
good map in mercator, you will see often that varying scale in the legend.
Fixing it. From memory, for spherical mercator scale is h=1/cos(lat), so
instead of 800, you would use 800/cos(lat). You need to be very careful
that the projection you use for a map is "fit for purpose". If distance
is important, then the distance from OL is meters on the projection and
you might want to correct that to true scale.
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