[Mapserver-users] Just call me a newbie . . . multiple Raster LAYERs question {Scanned} {Scanned}

Thu Mar 18 06:36:41 PST 2004

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Bob -
=20
You can use GDAL to create TIFF overviews and produce the same effect
(multiple resolutions stored in one file) without the expense or
overhead of MrSID.  Your performance should be essentially identical to
using the multiple-LAYER approach.
=20
    - Ed
Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242=20

  _____ =20

From: blammo [mailto:bob.basques at ci.stpaul.mn.us]=20
Sent: Thursday, March 18, 2004 9:06 AM
Cc: Mapserver List
Subject: Re: [Mapserver-users] Just call me a newbie . . . multiple
Raster LAYERs question {Scanned} {Scanned}

Siki Zoltan wrote:=20

	Hi,
=09
	On Wed, 17 Mar 2004, Bob Basques wrote:
=09
	 =20

		All,
	=09
		Let's say I have Six different levels of resolution of
Aerial Photo's =20
		all of them having the same coverage extents.
	=09
	=09
		   =20

=09
	It won't work.
	You should create six tile index and six layer and set MINSCALE
and=20
	MAXSCALE for them to turn the best one for a scale. You can add
them to
	the same group, so you can easily turn them on and off through
the group=20
	name.
	 =20

I got it to work as you (and others) described with seperate layers and
using the GROUP option.

	An other solution may be the sid format (may be the ecw to).
	As far as I know ecw is supported in the nightly built version.
	As far as I know MrSid is not supported :(
	These format can contain multi resolution image sources, that
case you can=20
	use the six different resolution tile as one image, that case no
need for=20
	tileindex.
	 =20

In my experience the MRSID option is too slow to render, I believe the
performance is (much) better using the seperate resolutions as LAYERS.

bobb

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<DIV dir=3Dltr align=3Dleft><SPAN class=3D229373514-18032004><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>Bob -</FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D229373514-18032004><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></SPAN> </DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D229373514-18032004><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>You can use GDAL to create TIFF overviews and =
produce the=20
same effect (multiple resolutions stored in one file) without the =
expense or=20
overhead of MrSID.  Your performance should be essentially =
identical to=20
using the multiple-LAYER approach.</FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D229373514-18032004><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></SPAN> </DIV>
<DIV dir=3Dltr align=3Dleft><SPAN =
class=3D229373514-18032004>    <FONT=20
face=3DArial color=3D#0000ff size=3D2>- Ed</FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D229373514-18032004>
<P><FONT size=3D2>Ed McNierney<BR>President and Chief =
Mapmaker<BR>TopoZone.com /=20
Maps a la carte, Inc.<BR>73 Princeton Street, Suite 305<BR>North =
Chelmsford,=20
MA  01863<BR>ed at topozone.com<BR>(978) 251-4242 =
</FONT></P></SPAN></DIV><BR>
<DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr align=3Dleft>
<HR tabIndex=3D-1>
<FONT face=3DTahoma size=3D2><B>From:</B> blammo=20
[mailto:bob.basques at ci.stpaul.mn.us] <BR><B>Sent:</B> Thursday, March =
18, 2004=20
9:06 AM<BR><B>Cc:</B> Mapserver List<BR><B>Subject:</B> Re: =
[Mapserver-users]=20
Just call me a newbie . . . multiple Raster LAYERs question {Scanned}=20
{Scanned}<BR></FONT><BR></DIV>
<DIV></DIV>Siki Zoltan wrote:=20
<BLOCKQUOTE =
cite=3DmidPine.LNX.4.44.0403180848480.20859-100000 at bme-geod.agt.bme.hu=20
type=3D"cite"><PRE wrap=3D"">Hi,

On Wed, 17 Mar 2004, Bob Basques wrote:

  </PRE>
  <BLOCKQUOTE type=3D"cite"><PRE wrap=3D"">All,

Let's say I have Six different levels of resolution of Aerial Photo's =20
all of them having the same coverage extents.

    </PRE></BLOCKQUOTE><PRE wrap=3D""><!---->
It won't work.
You should create six tile index and six layer and set MINSCALE and=20
MAXSCALE for them to turn the best one for a scale. You can add them to
the same group, so you can easily turn them on and off through the group =

name.
  </PRE></BLOCKQUOTE>I got it to work as you (and others) described with =

seperate layers and using the GROUP option.<BR>
<BLOCKQUOTE =
cite=3DmidPine.LNX.4.44.0403180848480.20859-100000 at bme-geod.agt.bme.hu=20
type=3D"cite"><PRE wrap=3D"">An other solution may be the sid format =
(may be the ecw to).
As far as I know ecw is supported in the nightly built version.
As far as I know MrSid is not supported :(
These format can contain multi resolution image sources, that case you =
can=20
use the six different resolution tile as one image, that case no need =
for=20
tileindex.
  </PRE></BLOCKQUOTE>In my experience the MRSID option is too slow to =
render, I=20
believe the performance is (much) better using the seperate resolutions =
as=20
LAYERS.<BR><BR>bobb<BR><BR></BODY></HTML>

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