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<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009>Hi,</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009>Is it necessary to show 2 m data at all in the areas
where 20-50 cm imagery is available? If not you can first make
tileindex shapefiles from 2 m images and 20-50 cm images. Open both
shapefiles with for example OpenJUMP and select and remove those polygons from 2
m shapefiles which are totally covered by you 20-50 cm tiles. Combine the
two layer, save and use the result as a tileindex file for
Mapserver.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009>There may be problems in the areas with overlapping
images. To get the desired image to show on top it may be necessary to
rewrite the shapefile by so that it will be ordered so that the small pixel size
images will be written last in the shapefile. Then they should be drawn on
top of 2 m imagery.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009>If you want the show 2 m images for the whole area when
zoomed far away, prepare still the combined shapefile with covered by -images
removed. Then make two scale dependent layers under the same group.
Read 2 m data when scale is between 200k and 100k and switch then to the
combined layer.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009>There may be better ways, this is the best I have
invented this far for our own use.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009>Take care of creating enough many low-resolution layers
with gdaladdo for far away zooms. Even then if Mapserver must open more
than 20-40 image files for filling the screen I would consider making a separate
overview image by mosaicing the whole area
together with something like 20-50-100 meter pixel size and using that
image in the same image group.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=793171012-16112009>-Jukka Rahkonen-</SPAN></FONT></DIV><BR>
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style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px">
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<FONT face=Tahoma size=2><B>Lähettäjä:</B>
mapserver-users-bounces@lists.osgeo.org
[mailto:mapserver-users-bounces@lists.osgeo.org] <B>Puolesta </B>Liang
Jian<BR><B>Lähetetty:</B> 16. marraskuuta 2009 13:02<BR><B>Vastaanottaja:</B>
mapserver-users@lists.osgeo.org<BR><B>Aihe:</B> [mapserver-users] performance
problem with ortho images<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV><FONT face=Arial size=2>
<DIV><SPAN class=996093710-16112009><FONT face=Arial size=2>Hi
all,</FONT></SPAN></DIV>
<DIV><SPAN class=996093710-16112009><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=996093710-16112009><FONT face=Arial size=2>I have a problem
with mapserver handling ortho images. The situation is we have 2m data cover
the whole country and 20-50cm data cover most cities. We setup mapfiles as 2m
data shows between scale 200k to 500 and 20-50cm data show between
scale 100k to 500. Problem is when requirst data in the city ranges, mapserver
first read data from 20-50cm dataset and then read from 2m dataset which is
unnecessary as the 20-50cm data is enough and the best solution is when there
is no 20-50cm data, 2m data should be used instead. </FONT></SPAN></DIV>
<DIV><SPAN class=996093710-16112009><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=996093710-16112009><FONT face=Arial size=2>Do you have any
idea how to avoid the unnecessary reading? </FONT></SPAN></DIV>
<DIV><SPAN class=996093710-16112009><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=996093710-16112009><FONT face=Arial size=2>Any suggestions
will be welcome!</FONT></SPAN></DIV>
<DIV><SPAN class=996093710-16112009><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=996093710-16112009><FONT face=Arial
size=2>Thanks</FONT></SPAN></DIV>
<DIV><SPAN class=996093710-16112009><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=996093710-16112009><FONT face=Arial
size=2>/Liang</FONT></SPAN></DIV></FONT></DIV><BR>
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