[OpenLayers-Users] How do we use MaxScaleDenominator andMinScaleDenominator

[Tim Schaub]

> WMS 1.3.0 has MinScaleDenominator and MaxScaleDenominator...
> these do not seem to correspond to setting minScale and 
> maxScale on a layer... does anyone know the translation between them?

The WMS spec assumes a pixel size of 0.28mm x 0.28mm in the definition of
MinScaleDenominator and MaxScaleDenominator.

OpenLayer assumes a "sensible default" of 72 dpi (or about 0.353mm pixel
width and height).  Change OpenLayers.DOTS_PER_INCH if you want this to be
different.

If I were you, I'd take the sensible path and boycott anything that relies
on scale (which depends on an agreement of pixel display size between client
and server), and use pixel resolution (map units per pixel) where ever
possible.

Tim


OpenLayers.DOTS_PER_INCH = 90.714; // should give you good behavior if you
have to use WMS 1.3