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<title>[mapguide-internals] RFC required for tile caching changes?</title>
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<DIV>
<DIV>Can you also give an example for tiles with negative indices?</DIV>
<DIV>For example if in the current scheme the tile is -33, -64, what would be
the resulting directory path?</DIV>
<DIV> </DIV>
<DIV>R-2/C-3/-3_-4</DIV>
<DIV> </DIV>
<DIV>What about tile -1,-1</DIV>
<DIV> </DIV>
<DIV>Another suggestion I have -- name the folder part of the path (30 *
tile index div 30) and then the file part would be (tile index mod
30).</DIV>
<DIV> </DIV>
<DIV>So for tile 33,64 the folder would be:</DIV>
<DIV> </DIV>
<DIV>Base Layer Group/30/60/3_4.png</DIV>
<DIV> </DIV>
<DIV>And for tile -33,-64 the folder would be:</DIV>
<DIV> </DIV>
<DIV>Base Layer Group/-30/-60/-3_-4.png</DIV>
<DIV> </DIV>
<DIV>For tile 1,1, the folder would be:</DIV>
<DIV> </DIV>
<DIV>Base Layer Group/0/0/1_1.png</DIV>
<DIV> </DIV>
<DIV>For tile -1,-1 the folder would be:</DIV>
<DIV> </DIV>
<DIV>Base Layer Group/-0/-0/-1_-1.png</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>It's a little weird around 0, but it allows for arbitrary
groupings of tiles in folders (they don't have to be 30x30) since the tile index
can be computed directly from the file path, by adding the folder term to the
file path term.</DIV>
<DIV> </DIV>
<DIV>Also, can you tell us what the problem is with having too many images in
one directory? Is it a file system issue? And how many tiles is the limit, i.e.
why is 30x30 the preferred grouping and not 1000x1000 for example?</DIV>
<DIV> </DIV>
<DIV>Traian</DIV></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV><FONT size=2>-----Original Message----- <BR><B>From:</B>
mapguide-internals-bounces@lists.osgeo.org on behalf of Jason Birch
<BR><B>Sent:</B> Fri 1/12/2007 8:57 PM <BR><B>To:</B> MapGuide Internals Mail
List <BR><B>Cc:</B> <BR><B>Subject:</B> RE: [mapguide-internals] RFC required
for tile caching changes?<BR><BR></FONT></DIV>
<DIV id=idOWAReplyText22625 dir=ltr>
<DIV dir=ltr><FONT face=Arial color=#000000 size=2>Can I forward this to the
"tiling" list for comment?</FONT></DIV>
<DIV dir=ltr><FONT face=Arial color=#000000 size=2></FONT> </DIV></DIV>
<DIV id=idSignature20507 dir=ltr>
<DIV><FONT color=#000000 size=2><FONT size=2>
<DIV></FONT></FONT><BR>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B>
mapguide-internals-bounces@lists.osgeo.org on behalf of Chris
Claydon<BR><B>Sent:</B> Fri 2007-01-12 12:24 PM<BR><B>To:</B> MapGuide
Internals Mail List<BR><B>Subject:</B> RE: [mapguide-internals] RFC required
for tile caching changes?<BR></FONT><BR></DIV></DIV></DIV>
<DIV>
<DIV class=Section1>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">A sample tile
location would be as follows:</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">……\</SPAN></FONT>
<FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Repositories\TileCache\Samples_Sheboygan_Maps_Sheboygan\7\Base
Layer Group\R2\C3\3_4.png</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">The R and C indices
correspond to rows and columns where each row contains 30 tiles vertically and
each column contains 30 tiles horizontally.</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">This indicates
that:</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal style="MARGIN-LEFT: 0.5in; TEXT-INDENT: -0.25in"><FONT
face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><SPAN>1)<FONT
face="Times New Roman" size=1><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></FONT></SPAN></SPAN></FONT><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">We’re at zoom level
7</SPAN></FONT></P>
<P class=MsoNormal style="MARGIN-LEFT: 0.5in; TEXT-INDENT: -0.25in"><FONT
face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><SPAN>2)<FONT
face="Times New Roman" size=1><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></FONT></SPAN></SPAN></FONT><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">We’re in grouped row
2</SPAN></FONT></P>
<P class=MsoNormal style="MARGIN-LEFT: 0.5in; TEXT-INDENT: -0.25in"><FONT
face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><SPAN>3)<FONT
face="Times New Roman" size=1><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></FONT></SPAN></SPAN></FONT><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">We’re in grouped
column 3</SPAN></FONT></P>
<P class=MsoNormal style="MARGIN-LEFT: 0.5in; TEXT-INDENT: -0.25in"><FONT
face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><SPAN>4)<FONT
face="Times New Roman" size=1><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></FONT></SPAN></SPAN></FONT><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">The tile location
within this grouped row/column combination is (3,4).</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">The R and C indices
never take a zero value (to avoid issues with negative values around the
origin), so this tile corresponds to a location of (33, 64) in the old
scheme.</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I took a quick look
at the Tile Map Service Specification, but it doesn’t appear to support the
concept of grouping blocks of tiles into subfolders in its current form. Can
you provide more information on whether this is possible?</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Chris.</SPAN></FONT></P>
<P class=MsoNormal><FONT face="Times New Roman" size=2><SPAN
style="FONT-SIZE: 10pt"></SPAN></FONT> </P></DIV></DIV></BLOCKQUOTE>
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