GeoWebCache is now built-in to GeoServer 1.7.1 and works with Openlayers tiling but MapBuilder 1.5 (rc1) tiling errors off

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GeoWebCache is now built-in to GeoServer 1.7.1 and works with Openlayers tiling but MapBuilder 1.5 (rc1) tiling errors off

John Mitchell
Hi,

GeoWebCache (a WMS tile-caching program) is now built-in to GeoServer 1.7.1 and works with Openlayers tiling but MapBuilder 1.5 (rc1) tiling errors off when the WMS request is sent to GeoWebCache.

Will upgrading to MapBuilder 1.5 (rc2) or the final version MapBuilder 1.5 (when it comes out) cause MapBuilder to generate tiles like the open layers demo within GeoServer 1.7.1?

The error is listed below:

400: Resolution (2.5111607142858094E-4) is not with 5.0% of the closest grid resolution (1.71661376953125E-4)


Below is the explanation of the error from the GeoWebCache website documentation:

Your bounds in the W direction are offset by more than 5% compared to the underlying grid.

Your bounds in the y direction are offset by more than 5% compared to the underlying grid.

This means tile size is correct (within 5%), but your request if not aligned to the grid that GeoWebCache uses. OpenLayers? can use the extent of the map, layer or some other parameters to automatically calculate this. The key thing is to provide maxExtent: new OpenLayers.Bounds(minx,miny,maxx,maxy) such that the values align to the grid of GWC. Basically this consists of taking the map zoomed all the way out (1 tile in EPSG:900913, 2 tiles in EPSG:4326) and then continuously dividing each tile into 4 equally sized tiles. The edges of these tiles represent the grid at each zoomlevel.


Thanks,

John
--
John J. Mitchell

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Re: GeoWebCache is now built-in to GeoServer 1.7.1 and works with Openlayers tiling but MapBuilder 1.5 (rc1) tiling errors off

Andreas Hocevar-2
Hey John,

I can only share my experiences with TileCache here, which does the
same as GeoWebCache, and this works fine with Mapbuilder 1.5.

Two things you have to take care of:

* You have to add a <resolutions> list in the mappaneol config, and
put in there a comma separated list of the resolutions you get from
GeoWebCache's GetCapabilities.

* The extent of your map must be the same as reported by GeoWebCache's
GetCapabilities, and you have to make sure that
displayOutsideMaxExtent is set to false (or not included) in the
mappaneol config.

Regards,
Andreas.

On Sun, Dec 14, 2008 at 12:23 AM, John Mitchell <[hidden email]> wrote:

> Hi,
>
> GeoWebCache (a WMS tile-caching program) is now built-in to GeoServer 1.7.1
> and works with Openlayers tiling but MapBuilder 1.5 (rc1) tiling errors off
> when the WMS request is sent to GeoWebCache.
>
> Will upgrading to MapBuilder 1.5 (rc2) or the final version MapBuilder 1.5
> (when it comes out) cause MapBuilder to generate tiles like the open layers
> demo within GeoServer 1.7.1?
>
> The error is listed below:
>
> 400: Resolution (2.5111607142858094E-4) is not with 5.0% of the closest grid
> resolution (1.71661376953125E-4)
>
> Below is the explanation of the error from the GeoWebCache website
> documentation:
>
> Your bounds in the W direction are offset by more than 5% compared to the
> underlying grid. ¶
>
> Your bounds in the y direction are offset by more than 5% compared to the
> underlying grid.
>
> This means tile size is correct (within 5%), but your request if not aligned
> to the grid that GeoWebCache uses. OpenLayers? can use the extent of the
> map, layer or some other parameters to automatically calculate this. The key
> thing is to provide maxExtent: new OpenLayers.Bounds(minx,miny,maxx,maxy)
> such that the values align to the grid of GWC. Basically this consists of
> taking the map zoomed all the way out (1 tile in EPSG:900913, 2 tiles in
> EPSG:4326) and then continuously dividing each tile into 4 equally sized
> tiles. The edges of these tiles represent the grid at each zoomlevel.
>
> Thanks,
>
> John
> --
> John J. Mitchell
>
> ------------------------------------------------------------------------------
> SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada.
> The future of the web can't happen without you.  Join us at MIX09 to help
> pave the way to the Next Web now. Learn more and register at
> http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/
> _______________________________________________
> mapbuilder-devel mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/mapbuilder-devel
>
>



--
Andreas Hocevar
OpenGeo - http://opengeo.org/
Expert service straight from the developers.

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Re: GeoWebCache is now built-in to GeoServer 1.7.1 and works with Openlayers tiling but MapBuilder 1.5 (rc1) tiling errors off

John Mitchell
Andreas,

Thanks for the tip!!!

Adding the resolutions to the mappaneol config file now allows me to cache within MapBuilder 1.5.

I now can display over a million features in 1-3 seconds.

Thanks,

John

On Tue, Dec 16, 2008 at 7:37 AM, Andreas Hocevar <[hidden email]> wrote:
Hey John,

I can only share my experiences with TileCache here, which does the
same as GeoWebCache, and this works fine with Mapbuilder 1.5.

Two things you have to take care of:

* You have to add a <resolutions> list in the mappaneol config, and
put in there a comma separated list of the resolutions you get from
GeoWebCache's GetCapabilities.

* The extent of your map must be the same as reported by GeoWebCache's
GetCapabilities, and you have to make sure that
displayOutsideMaxExtent is set to false (or not included) in the
mappaneol config.

Regards,
Andreas.

On Sun, Dec 14, 2008 at 12:23 AM, John Mitchell <[hidden email]> wrote:
> Hi,
>
> GeoWebCache (a WMS tile-caching program) is now built-in to GeoServer 1.7.1
> and works with Openlayers tiling but MapBuilder 1.5 (rc1) tiling errors off
> when the WMS request is sent to GeoWebCache.
>
> Will upgrading to MapBuilder 1.5 (rc2) or the final version MapBuilder 1.5
> (when it comes out) cause MapBuilder to generate tiles like the open layers
> demo within GeoServer 1.7.1?
>
> The error is listed below:
>
> 400: Resolution (2.5111607142858094E-4) is not with 5.0% of the closest grid
> resolution (1.71661376953125E-4)
>
> Below is the explanation of the error from the GeoWebCache website
> documentation:
>
> Your bounds in the W direction are offset by more than 5% compared to the
> underlying grid. ¶
>
> Your bounds in the y direction are offset by more than 5% compared to the
> underlying grid.
>
> This means tile size is correct (within 5%), but your request if not aligned
> to the grid that GeoWebCache uses. OpenLayers? can use the extent of the
> map, layer or some other parameters to automatically calculate this. The key
> thing is to provide maxExtent: new OpenLayers.Bounds(minx,miny,maxx,maxy)
> such that the values align to the grid of GWC. Basically this consists of
> taking the map zoomed all the way out (1 tile in EPSG:900913, 2 tiles in
> EPSG:4326) and then continuously dividing each tile into 4 equally sized
> tiles. The edges of these tiles represent the grid at each zoomlevel.
>
> Thanks,
>
> John
> --
> John J. Mitchell
>
> ------------------------------------------------------------------------------
> SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada.
> The future of the web can't happen without you.  Join us at MIX09 to help
> pave the way to the Next Web now. Learn more and register at
> http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/
> _______________________________________________
> mapbuilder-devel mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/mapbuilder-devel
>
>



--
Andreas Hocevar
OpenGeo - http://opengeo.org/
Expert service straight from the developers.



--
John J. Mitchell

------------------------------------------------------------------------------
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