[Mapserver-users] Performence hit when projecting to lat long ?

[Omry Yadan]

I tried the DLLs you have sent, I didn't see any improvement over my
existing ones (1.6.5.243).

About your suggestions:
1. I think that’s what I'll do, but first I'll send a more complete
description of my problem to the group, maybe someone will have a better
idea.
2. Its probably an option, but when not re-projecting, ECW performed quite
well.
3. What I have at hand is just a sample of the real thing.. it will probably
contain much more tiles than just two.


-----Original Message-----
From: Brent Fraser [mailto:bfraser at geoanalytic.com] 
Sent: â 14 àå÷èåáø 2003 19:15
To: Omry Yadan; mapserver-users at lists.gis.umn.edu
Subject: Re: [Mapserver-users] Performence hit when projecting to lat long?

I've seen this as well.  I was using ECW dlls stamped as version 1.7.0.424
When I switched to a set stamped 1.6.6.32 the memory usage dropped
dramatically.  I'll send you a set in a separate email...

It may not solve much of the speed problem (other than the memory allocation
part).  Most of the time will be spent re-projecting.  If possible you would
want to avoid this by creating source datasets in the target coordinate
system.

If speed is your criteria and you have 10's of gigabytes available, you may
want to:
1. Avoid re-projection
2. Avoid using compressed files
3. Produce a tiled dataset with more tiles that just two.

Brent Fraser
GeoAnalytic Inc.

----- Original Message -----
From: "Omry Yadan" <omry at telmap.com>
To: <mapserver-users at lists.gis.umn.edu>
Sent: Tuesday, October 14, 2003 10:25 AM
Subject: [Mapserver-users] Performence hit when projecting to lat long?


> I tried to display a map in lat/long bounding box using this url:
>
http://omry/cgi-bin/mapserv40.exe?map=/projects/nat/nat.map&REQUEST=GetMap&V
> ERSION=1&bbox=34.9098,32.2125,35.1034,32.3925&width=1000&height=1000
>
> I get the map, but it takes forever (around a minute), in which I see the
> memory footprint of the server goes up over 100mb.
> I suspect the projection to lat long is the problem.
>
> Additional info:
> The data is two tiles in ecw format, total ecw files size if 223mb.
>
> Any insights?
> Suggestions?
>
>
> Thanks.
>
>
> MAP
> NAME "Natanya sample file"
>
> IMAGETYPE JPEG
> SIZE 1000 1000
> #EXTENT 182400.375 679996.265 210002.835 700002.575
> EXTENT 34.9098 32.2125 35.1034 32.3925
>
>
> WEB
> METADATA
> "wms_title"                  "WMS Demo Server"
> "wms_onlineresource"
> "http://omry/cgi-bin/mapserv?map=nat.map&"
> END
> END
>
> PROJECTION
> proj=latlong
> ellps=WGS84
> END
>
>
> LAYER
> PROJECTION
> "init=epsg:2039"
> END
>
> NAME "Natanya arial photo"
> STATUS DEFAULT
> TILEINDEX "ntn.shp"
> TILEITEM "location"
> TYPE RASTER
> END
>
> END # Map File
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