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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Chris this is a great idea.&nbsp;
Especially in my line of work/applications where we display thematic maps that don&#8217;t
allow even near complete caches of maps or tiles.&nbsp; Our work in <a
href="http://www.dataplace.org/">http://www.dataplace.org</a> (for fannie mae
foundation &#8211; along with Vinq) has relied on the simple <o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<p class=MsoNormal style='margin-left:.75in;text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'><span style='mso-list:Ignore'>1.<font size=1 face="Times New Roman"><span
style='font:7.0pt "Times New Roman"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></font></span></span></font><![endif]><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>check tile cache<o:p></o:p></span></font></p>

<p class=MsoNormal style='margin-left:.75in;text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'><span style='mso-list:Ignore'>2.<font size=1 face="Times New Roman"><span
style='font:7.0pt "Times New Roman"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></font></span></span></font><![endif]><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>generate complete map (with thematic shading and layers)<o:p></o:p></span></font></p>

<p class=MsoNormal style='margin-left:.75in;text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'><span style='mso-list:Ignore'>3.<font size=1 face="Times New Roman"><span
style='font:7.0pt "Times New Roman"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></font></span></span></font><![endif]><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>slice tiles<o:p></o:p></span></font></p>

<p class=MsoNormal style='margin-left:.75in;text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'><span style='mso-list:Ignore'>4.<font size=1 face="Times New Roman"><span
style='font:7.0pt "Times New Roman"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></font></span></span></font><![endif]><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>cache tiles<o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>approach.&nbsp; Our cache though currently
large enough to have some recurring cache hits, won&#8217;t be able to be large
enough for the future of our app.&nbsp; That is we want to add more indicators
to our system (and thus many more potential maps being generated).&nbsp; As
well we want to add more complicated maps and chart shields as labels.&nbsp; &nbsp;The
universe of maps even with Terabyte drives won&#8217;t be covered by
pre-rendering.<o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>We have been aiming towards a client side
rendering solution to increase our cache hits.&nbsp; I&#8217;m curious, has
anyone tried rendering a map with transparencies created by map server? &nbsp;&nbsp;I.e.
essentially doing what Chris suggested?&nbsp; Are the maps as pretty on Firefox
(given that IE doesn&#8217;t support full alpha-channel usage in PNG&#8217;s)?<o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>As well, has anyone looked at the approach
of actually rendering the layers (placing them on the map) one by one on the
client?&nbsp; I know this delves into fattening the client beyond the abilities
of javascript, but I&#8217;m curious if this has been discussed in the ka-map group.<o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Thanks,<o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Moran Ben-David<o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Placebase (www.place-base.com)<o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

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<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>

<hr size=2 width="100%" align=center tabindex=-1>

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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
ka-map-users-bounces@lists.maptools.org
[mailto:ka-map-users-bounces@lists.maptools.org] <b><span style='font-weight:
bold'>On Behalf Of </span></b>Chris Tweedie<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, May 24, 2005 3:05
AM<br>
<b><span style='font-weight:bold'>To:</span></b>
ka-map-users@lists.maptools.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> [ka-Map-users] Layer
Interaction/Overlays</span></font><o:p></o:p></p>

</div>

<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p>&nbsp;</o:p></span></font></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>To Paul / rest of the devs, what&#8217;s your
thoughts on adding transparency to the tiles and allowing tile/layer overlays?
I see you have commented out the following, so you may be already looking at
this?</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>&nbsp;</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // TODO:
We don't need transparency for now</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
//$oMap-&gt;outputformat-&gt;set(&quot;transparent&quot;, MS_ON );</span></font><span
lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>&nbsp;</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>Im looking at instead of creating the tiled images
based on all layers in the map file, I would add a new config switch to specify
particular layers that you wish to split into separate tiles. Ideally, this
would allow particular layers in the map to be toggled on/off and be moved
hierarchically all on the client side.</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>&nbsp;</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>Advantages:</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal style='margin-left:.5in;text-indent:-.25in'><font size=2
face=Arial><span lang=EN-AU style='font-size:10.0pt;font-family:Arial'>-</span></font><font
size=1><span lang=EN-AU style='font-size:7.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span></font><font size=2 face=Arial><span lang=EN-AU style='font-size:10.0pt;
font-family:Arial'>Complete client side transparency / z-index position using
CSS / DOM / JS</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal style='margin-left:.5in;text-indent:-.25in'><font size=2
face=Arial><span lang=EN-AU style='font-size:10.0pt;font-family:Arial'>-</span></font><font
size=1><span lang=EN-AU style='font-size:7.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span></font><font size=2 face=Arial><span lang=EN-AU style='font-size:10.0pt;
font-family:Arial'>Same benefits with cached tiles but further functionality</span></font><span
lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal style='margin-left:.5in;text-indent:-.25in'><font size=2
face=Arial><span lang=EN-AU style='font-size:10.0pt;font-family:Arial'>-</span></font><font
size=1><span lang=EN-AU style='font-size:7.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span></font><font size=2 face=Arial><span lang=EN-AU style='font-size:10.0pt;
font-family:Arial'>Remove reliance on the server regenerating images to perform
simple layer ordering functions</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal style='margin-left:.5in;text-indent:-.25in'><font size=2
face=Arial><span lang=EN-AU style='font-size:10.0pt;font-family:Arial'>-</span></font><font
size=1><span lang=EN-AU style='font-size:7.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span></font><font size=2 face=Arial><span lang=EN-AU style='font-size:10.0pt;
font-family:Arial'>Will suit the planned cache refresh function seen on
bugzilla. If a layer data source is updated, only related layer images need to
be flushed, not everything.</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>&nbsp;</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>Disadvantages:</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal style='margin-left:.5in;text-indent:-.25in'><font size=2
face=Arial><span lang=EN-AU style='font-size:10.0pt;font-family:Arial'>-</span></font><font
size=1><span lang=EN-AU style='font-size:7.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span></font><font size=2 face=Arial><span lang=EN-AU style='font-size:10.0pt;
font-family:Arial'>Cross browser support issues</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal style='margin-left:.5in;text-indent:-.25in'><font size=2
face=Arial><span lang=EN-AU style='font-size:10.0pt;font-family:Arial'>-</span></font><font
size=1><span lang=EN-AU style='font-size:7.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span></font><font size=2 face=Arial><span lang=EN-AU style='font-size:10.0pt;
font-family:Arial'>Integration with current code would require directory and
tile algorithm change</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal style='margin-left:.5in;text-indent:-.25in'><font size=2
face=Arial><span lang=EN-AU style='font-size:10.0pt;font-family:Arial'>-</span></font><font
size=1><span lang=EN-AU style='font-size:7.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span></font><font size=2 face=Arial><span lang=EN-AU style='font-size:10.0pt;
font-family:Arial'>Annotation clashes due to the images being created
independently. ie. labels and symbols may become illegible</span></font><span
lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal style='margin-left:.5in;text-indent:-.25in'><font size=2
face=Arial><span lang=EN-AU style='font-size:10.0pt;font-family:Arial'>-</span></font><font
size=1><span lang=EN-AU style='font-size:7.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span></font><font size=2 face=Arial><span lang=EN-AU style='font-size:10.0pt;
font-family:Arial'>Increased overhead downloading images</span></font><span
lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>&nbsp;</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>While the download overhead may be significant
depending on the number of images you wish to overlay, typically you&#8217;d
limit the amount of layers available to be moved/turned off. However as the
xmlhttprequest handles concurrent downloading of images, I&#8217;d expect most
users will not notice the increased data as they can continue to zoom/pan.</span></font><span
lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>&nbsp;</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>Thoughts/Opinions? Thought I&#8217;d throw the idea
out there and gauge a response. Afterall, no point reinventing the wheel </span></font><font
size=2 face=Wingdings><span lang=EN-AU style='font-size:10.0pt;font-family:
Wingdings'>J</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>&nbsp;</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=1 color=black face=Arial><span lang=EN-AU
style='font-size:7.5pt;font-family:Arial;color:black'>---------------------------------------------------------------------------</span></font><span
lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><strong><b><font size=2 face=Arial><span lang=EN-AU
style='font-size:10.0pt;font-family:Arial'>Chris Tweedie</span></font></b></strong><span
lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>Technical Officer</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>Shared Land Services</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=1 face=Arial><span lang=EN-AU style='font-size:
7.5pt;font-family:Arial'>Department of Land Information</span></font><span
lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><st1:address w:st="on"><st1:Street w:st="on"><font size=1
  face=Arial><span lang=EN-AU style='font-size:7.5pt;font-family:Arial'>1
  Midland Square</span></font></st1:Street><font size=1 face=Arial><span
 lang=EN-AU style='font-size:7.5pt;font-family:Arial'>, <st1:City w:st="on">Midland</st1:City>,
 <st1:State w:st="on">Western Australia</st1:State></span></font></st1:address><font
size=1 face=Arial><span lang=EN-AU style='font-size:7.5pt;font-family:Arial'>
6056</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><st1:address w:st="on"><st1:Street w:st="on"><font size=1
  face=Arial><span lang=EN-AU style='font-size:7.5pt;font-family:Arial'>PO Box
  2222</span></font></st1:Street><font size=1 face=Arial><span lang=EN-AU
 style='font-size:7.5pt;font-family:Arial'> <st1:City w:st="on">Midland</st1:City></span></font></st1:address><font
size=1 face=Arial><span lang=EN-AU style='font-size:7.5pt;font-family:Arial'>
6936</span></font><span lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=1 face=Arial><span lang=EN-AU style='font-size:
7.5pt;font-family:Arial'>Telephone: (08) 9273 7520 Facsimile (08) 9273 7638</span></font><span
lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=1 face=Arial><span lang=EN-AU style='font-size:
7.5pt;font-family:Arial'>Email: </span></font><font face=Arial><span
lang=EN-AU style='font-family:Arial'><a
href="mailto:chris.tweedie@dli.wa.gov.au"><font size=1><span style='font-size:
7.5pt'>chris.tweedie@dli.wa.gov.au</span></font></a></span></font><span
lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=1 face=Arial><span lang=EN-AU style='font-size:
7.5pt;font-family:Arial'>Website: </span></font><font face=Arial><span
lang=EN-AU style='font-family:Arial'><a href="http://www.dli.wa.gov.au"><font
size=1><span style='font-size:7.5pt'>www.dli.wa.gov.au</span></font></a></span></font><span
lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=1 face=Arial><span lang=EN-AU style='font-size:
7.5pt;font-family:Arial'>---------------------------------------------------------------------------</span></font><span
lang=EN-AU><o:p></o:p></span></p>

<p class=MsoNormal><font size=3 face="Times New Roman"><span lang=EN-AU
style='font-size:12.0pt'>&nbsp;<o:p></o:p></span></font></p>

<p class=MsoNormal><font size=3 face="Times New Roman"><span lang=EN-AU
style='font-size:12.0pt'><br>
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