[OpenLayers-Users] Used gdal2tiles to create several TMS spec maps for Openlayers, but the Overview Map shows the wrong part of the picture!

[Fernando]

>
> Hi Connor,
>
> First of all congratulations for a fantastic and inovative use of
> OpenLayers that I'd never imagine before.
>
> The site that you sent that link doesn't work for me, I can't find the
> OpenLayers use, and try to understand what is the 'inaccurate' thing you
> talking about.
>
NOTE: I saw a javascript error in your master.js line 83:
map.addControl(new OpenLayers.Control.OverviewMap({div:overviewdiv,size:new
OpenLayers.Size(200,100),minRectSize:1,maxRatio:1028,mapOptions:{restrictedExtent:borders,maxResolution:maxres}}));

ERROR: overviewdiv is not defined

Use quotes to the overviewdiv, or they will threat this like a variable,
instead the string of the id declared in the div.



>
> Imagining how that you are using for a non geospatial solution, and how
> the tiles generally works, I guess that the problem is about the
> projection.
> A projection it's a reference to the space, it's used to determine
> Extents, Bounds, Scales and resolutions for the coordinates. The tiles
> depends of this variables to split than according to the zoom level.
> Maybe the most difficult thing it's create a based projection (or SRS) to
> the microscopical spatial, that different from earth maybe is flat and with
> ends, instead of 'round' and continuos.
>
> Keep me updated, because i'm curious about this use and hope for your
> success.
>
> Att,
>
> Fernando G. Norte
> BHte - MG
> cel: +55 31 9119 8814
> -------------------------
> MSN e Gtalk # fnorte at gmail.com
>
>
> Em 22 de março de 2012 00:20, Connor Burke <connor.p.b at gmail.com>escreveu:
>
>>  I'm a student at the Ohio State University medical school, and am
>> working on a histology website. Basically, I've used gdal2tiles.py to tile
>> a few hundred images (several GB each) taken from microscopes - of cells
>> and other tissue - and display them using OpenLayers. It's been quite an
>> exciting project, and already represents an improvement over the current
>> system, which uses Zoomify (a flash based alternative) for the same thing.
>>
>> For those who aren't familiar with gdal2tiles, it breaks images up into
>> 256px tiles and stores them in a folder structure in accordance with TMS
>> specifications. You can set a spatial reference system and map projection
>> if you want, but I just tile them with nothing, as plain raster images. It
>> then generates a little HTML file that uses OpenLayers and a tiny bit of
>> its own Javascript to read the tiles off the server you put them on.
>>
>> Here's the problem - the overview map is inaccurate. It shows the image,
>> but off center - and the extent rectangle that shows where I'm zooming is
>> simply inaccurate. I've spent a while trying to troubleshoot this on my own
>> and am out of ideas.
>>
>> Here's the site -
>> http://histology.osumc.edu/test/tiled1.php
>>
>> (note how you can zoom to the center of the spinal cord, but the overview
>> map shows that we're zooming into the bottom left)
>>
>> Any help would be much appreciated - thanks guys.
>>
>> Connor
>>
>> _______________________________________________
>> Users mailing list
>> Users at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/openlayers-users
>>
>>
>
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