[OpenLayers-Users] RE: Google Terrian map does not align with geometry

[JK Chen]

OpenLayers's Google Terrain map can only zoom to 16. If setting the numZoomLevels to any value bigger than 16, then when zooming into those levels, the base map stay unchanged (which is a bug), which in turn causes vector layer to be misaligned, because the vector layer (the polygons) has been zoom in "correctly".

The maps from Google server has 20 levels. But within Openlayers, those levels are not being drawn. And it acts like it is drawing.

JK

From: Nicholas Efremov-Kendall [mailto:n.e.kendall at gmail.com]
Sent: Wednesday, June 15, 2011 3:20 PM
To: JK Chen
Cc: openlayers-users at lists.osgeo.org
Subject: Re: [OpenLayers-Users] RE: Google Terrian map does not align with geometry

rather, the layers can support different zoom levels, maybe there's a conflict there.
On Wed, Jun 15, 2011 at 4:18 PM, Nicholas Efremov-Kendall <n.e.kendall at gmail.com<mailto:n.e.kendall at gmail.com>> wrote:
Hi JK,

The googles layers actually have different zoom levels, sometimes going to hybrid goes to 21, physical goes to 22 and such. Look up the maxzoom for the terrain layer, that might fix your problem.
On Wed, Jun 15, 2011 at 4:05 PM, JK Chen <jk.chen at sdl.usu.edu<mailto:jk.chen at sdl.usu.edu>> wrote:

These misalignments happen at zoom levels greater than or equal to 16. As you might know, Google  Terrain provides 20 zoom levels. Apparently this is a bug within Openlayers.
My current "workaround" is to set the numZoomlevels to 16 for Google Terrain map.

Thanks.

JK
From: openlayers-users-bounces at lists.osgeo.org<mailto:openlayers-users-bounces at lists.osgeo.org> [mailto:openlayers-users-bounces at lists.osgeo.org<mailto:openlayers-users-bounces at lists.osgeo.org>] On Behalf Of JK Chen
Sent: Wednesday, June 15, 2011 1:52 PM
To: openlayers-users at lists.osgeo.org<mailto:openlayers-users at lists.osgeo.org>
Subject: [OpenLayers-Users] Google Terrian map does not align with geometry

Hi,

My application draws many geometries (basically, polygons, each representing captured aerial images). All of my geometries align correctly with Google Street, Satellite, Hybrid maps, but not correctly with Google Terrian map.

While in Google Terrian map, when I zoom in to say zoom levels more than 10, the mis-alignment starts to show up, and another issue also starts showing up, the rectangle of my geometry becomes movable. All of these are simply wrong. These will render the application unreliable which means useless for our users.

Can anyone share some thoughts about these behaviors? How to fix them?

How Reliable is OpenLayers? I'm seeing many un-reliability and inconsistence.

Thanks.

JK

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