Structuring rasters?

[Ed McNierney]

Jeff -

No problem; thanks for the update.

As an example, a 400-km by 400-km square at 1-meter resolution would be 160
billion pixels.  That's 160 GB of 8-bit data or 480 GB or 24-bit data,
uncompressed.  Storing it as a group of individual images (1,600 10-km by
10-km tiles) with a TILEINDEX will let you serve it as one layer.  Using a
RAID-5 array will help performance, as will using SCSI drives (esp. 15K RPM
drives).  There are some optimizations that will particularly help
scalability (sustain performance under growing user load) that wouldn't be
needed if you have a small number of users.  If you need to view at
zoomed-out levels some extra disk space for pre-built overviews would be
helpful (you never need more than 50% more than the original space for
overviews).

     - Ed

-- 
Ed McNierney
President and Chief Mapmaker
Maps a la carte, Inc. / TopoZone.com
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
Phone: (978) 251-4242
Fax: (978) 251-1396
ed at topozone.com

> From: Jeff Dege <jdege at KORTERRA.COM>
> Reply-To: Jeff Dege <jdege at KORTERRA.COM>
> Date: Fri, 18 May 2007 15:47:02 -0500
> To: <MAPSERVER-USERS at LISTS.UMN.EDU>
> Conversation: [UMN_MAPSERVER-USERS] Structuring rasters?
> Subject: Re: [UMN_MAPSERVER-USERS] Structuring rasters?
> 
>> -----Original Message-----
>> From: Ed McNierney [mailto:ed at topozone.com]
>> Sent: Friday, May 18, 2007 3:15 PM
>> To: Jeff Dege; MAPSERVER-USERS at LISTS.UMN.EDU
>> Subject: Re: [UMN_MAPSERVER-USERS] Structuring rasters?
>> 
>> Jeff -
>> 
>> And how large is that?  I didn't say put it in one TIFF - I
>> asked how much
>> data you have.
> 
> Don't know, yet.  The customer has yet to supply us with it.  The extent
> I know.  I've asked what resolution they're supplying us with, and what
> resolution they think they need, but haven't yet had answers.
>  
>> Please reply to the whole list so this will go in the
>> archives, just like
>> the other replies I've made to inquiries like this <g>.
> 
> This is the only mailing list I've ever subscribed to where a reply went
> to the author, rather than to the list.  I have tried to remember, but I
> expect this won't be the last time I make that mistake.