[OpenLayers-Users] Problems with scaling when Virtual Earth is the base layer?

[Richard Marsden]

I don't know if anyone has seen this, or know of a workaround, but I'm 
finding that if I zoom in too far with a Virtual Earth base layer, then 
the other layers are not plotted.

Eg.

http://www.ecomapcostarica.com/map/map_test_ve.shtml

( I've found problems when trying to switch base layers between 
MapServer WMS and Virtual Earth. It will switch from VE to MPS 
perfectly, but not back again. My solution was to have two pages: one 
for each base layer. The above page is the draft version of the VE page)

The default zoom (also duplicated with the Leaves and Lizards zoom 
option) plots at the maximum zoom that works. What you see is a KML 
layer, on top of a raster image and a 'stream' vector layer (both from 
MapServer WMS). No VE should be visible, but if you pan to the north VE 
should be visible.

In fact we're zoomed in too far and VE shows the "forbidden camera" icon 
indicating that  sufficiently detailed images are unavailable. This is 
to be expected. However if we zoom in one step further (eg. by scrolling 
the mouse wheel one click), then OpenLayers appears to 'hang' with the 
VE layer and does not show the other layers.

This is actually quite limiting for this application, because virtually 
everything of interest will be plotted in the red KML polygon!

So does anyone know of a workaround, eg. is it possible to make the VE 
base layer automatically appear and disappear when zoomed in very far?

As an aside, the working non-VE version which uses public outline SHP 
data instead, can be seen here:

http://www.ecomapcostarica.com/map/index.shtml

We shall be in the field in two weeks time, and hope to update the 
map(s) whilst we're out there.  Yes Wifi has even reached the rainforest!!


Richard
-- 
Richard Marsden
Winwaed Software Technology LLC
http://www.winwaed.com
Tools and Add-ins for MapPoint - http://www.mapping-tools.com