[OpenLayers-Users] Problems with setting maxExtent

[John Roberts]

Dear All

I hope you might be able to help.

I am have just started learning OpenLayers and I finding it a very
interesting product.

However I am having problems setting a maxExtent. I create a map with the
maxExtent defined as below (2500 x 2500 metres).
I then try to set the map to open up at the maxExtent.

However when I use:

1. zoomToExtent(maxBounds) or zoomToMaxExtent(), the view is returned as as
approx 1000 by 700 metres, positioned at what appears the centre of the
maxExtent. The zoom bar is set to 17, so I am unable to zoom out any more.
However I can pan to the rest of the extent.

2. map.setCenter(new OpenLayers.LonLat(-3.75,51.56), 6);: the view is
returned much zoomed in, and when I zoom out to the maximum extent using the
zoom bar, I am returned to the original extent of 1000 by 700 metres!

I suspect that I am missing something simple, but I just cannot see it! Has
anybody got any suggestions?

Thanking you in advance.

John
Manchester, UK

P.S. I attach the relevant bits of the HTML file below

----------------------------------------------------------------------------
----------------------------------------------
/* bounding box of 2500 metres by 2500 metres */
var maxBounds = new OpenLayers.Bounds(277750,185750,280250,188250);


var map = new OpenLayers.Map('map',{maxExtent: maxBounds,maxResolution:
1.40, units: 'meters', projection: "EPSG:27700"});

/* here I create 6 layers based on GeoServer WMS which all have extents
approx equal to the bounds above */

map.addLayers([mmAreaC,mmAreaBW,mmLine,mmITN,mmAdpnt,mmText]);

map.addControl(new OpenLayers.Control.OverviewMap());
map.addControl(new OpenLayers.Control.PanZoomBar());
map.addControl(new OpenLayers.Control.LayerSwitcher());
map.addControl(new OpenLayers.Control.MousePosition());

map.zoomToMaxExtent();
/* map.zoomToExtent(maxBounds); */
/* map.setCenter(new OpenLayers.LonLat(-3.75,51.56), 6); */