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

[Bob Basques]

Ed McNierney wrote:

> Bob -
>  
> 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.
>
I already have systems for generating the seperate tiles at each Level 
of resolution.

The ranges are fairly extreme for the number of tiles per resolution level.

9000+ tiles at 1/2 foot per pixel
down to
~16 tiles at 16 feet per pixel

I'm not sure how the performance can be increased at the server 
(intranet installation, which typically means optimizing the server vs 
the file transfers) using a combined lookup of some sort.

bobb

>  
>     - 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
>
>
> ------------------------------------------------------------------------
> *From:* blammo [mailto:bob.basques at ci.stpaul.mn.us]
> *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:
>
>>Hi,
>>
>>On Wed, 17 Mar 2004, Bob Basques wrote:
>>
>>  
>>
>>>All,
>>>
>>>Let's say I have Six different levels of resolution of Aerial Photo's  
>>>all of them having the same coverage extents.
>>>
>>>
>>>    
>>>
>>
>>It won't work.
>>You should create six tile index and six layer and set MINSCALE and 
>>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.
>>  
>>
> 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 
>>use the six different resolution tile as one image, that case no need for 
>>tileindex.
>>  
>>
> 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
>