Well it should be quite simple.. something like this probably, but don't blame me if it's wrong.<br>( (maxx-minx)/(units-per-pixel<div id="1ez9" class="ArwC7c ckChnd">*tilewidth) ) * ( (maxy-miny)/(units-per-pixel*tileheight) )<br>
<br>About
image compression you got png and jpeg.. png is best for lines, text
etc. (and transparency) and jpeg is best for photographic imagery. Jpeg
is degrading so you'll have to choose a compression ratio that suits
the purpose, png uses zip-like compression so there is no real reason
to not use highest compression (I think?).You can strip both of these
formats from metadata if you want to make sure the files are as small
as possible (might actually make quite a difference on millions of
tiles).<br><font color="#888888">
<br>/Björn</font></div><br><br><div class="gmail_quote">On Feb 5, 2008 11:21 PM, David R Robison <<a href="mailto:drrobison@openroadsconsulting.com">drrobison@openroadsconsulting.com</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div bgcolor="#ffffff" text="#000000">
Could you give me the formula for calculating the number of tiles?
Also, do you have any tips about format/compression/metadata? TNX David<br>
<br>
Björn Harrtell wrote:
<blockquote type="cite"><div><div></div><div class="Wj3C7c">You can calculate the number of tiles exactly (obviously)
but the problem is the actual tile image sizes will depend on what kind
of map you have... blank/ocean areas and photographic imagery beeing
the most important factors. That's why optimizing the image output
(format/compression/metadata) from your mapserver is quite important.
What you could do is try to determine what the largest tile image would
be and use that multiplied number of tiles as the estimated maximum
size for the cache.<br>
<br>
/Björn<br>
<br>
<div class="gmail_quote">On Feb 5, 2008 10:58 PM, David R Robison <<a href="mailto:drrobison@openroadsconsulting.com" target="_blank">drrobison@openroadsconsulting.com</a>>
wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Is
there a simple formula for estimating the disk space requirements for<br>
the tile cache? Thanks, David<br>
<br>
--<br>
<br>
David R Robison<br>
Open Roads Consulting, Inc.<br>
708 S. Battlefield Blvd., Chesapeake, VA 23322<br>
phone: (757) 546-3401<br>
e-mail: <a href="mailto:drrobison@openroadsconsulting.com" target="_blank">drrobison@openroadsconsulting.com</a><br>
web: <a href="http://openroadsconsulting.com" target="_blank">http://openroadsconsulting.com</a><br>
blog: <a href="http://therobe.blogspot.com" target="_blank">http://therobe.blogspot.com</a><br>
book: <a href="http://www.xulonpress.com/book_detail.php?id=2579" target="_blank">http://www.xulonpress.com/book_detail.php?id=2579</a><br>
<br>
<br>
<br>
<br>
<br>
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</blockquote>
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<br>
</div></div><pre><hr size="4" width="90%"><div class="Ih2E3d">
_______________________________________________
Tilecache mailing list
<a href="mailto:Tilecache@openlayers.org" target="_blank">Tilecache@openlayers.org</a>
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</blockquote>
<br>
<pre cols="72">--
David R Robison
Open Roads Consulting, Inc.
708 S. Battlefield Blvd., Chesapeake, VA 23322
phone: (757) 546-3401
e-mail: <a href="mailto:drrobison@openroadsconsulting.com" target="_blank">drrobison@openroadsconsulting.com</a><div class="Ih2E3d">
web: <a href="http://openroadsconsulting.com" target="_blank">http://openroadsconsulting.com</a>
blog: <a href="http://therobe.blogspot.com" target="_blank">http://therobe.blogspot.com</a>
book: <a href="http://www.xulonpress.com/book_detail.php?id=2579" target="_blank">http://www.xulonpress.com/book_detail.php?id=2579</a>
</div></pre>
</div>
</blockquote></div><br>