[OSGeo-Discuss] fastest option of serving huge imagery on web map on the fly

[miblon]

If mapserver is to slow, almost everything else is to slow... I also 
noticed your crosspost on the mapproxy list. mapproxy will even cache to 
more then the 60TB youve estimated, because it will cache every wms 
request instead of square, stitched tiles.

If I where you and caching is an issue, I would invest in a (small) farm 
of fast cgi mapserver servers with for instance a squid proxy in front.
One single machine will always be to slow. You say nothing about the 
hardware. I for instance use i7 950 servers with 12Gb ram and 3Tb 
diskspace for €89 a month.

- Search for the best hardware at acceptable price
- Consider setting up less servers with more diskspace per server and 
concider using cache if you find out that the cost of individual high 
end large disks (with in total enough space to hold 120Tb or so) are 
lower then setting up 4 individual machines with less diskspace barely 
fitting your initial dataset, consider that too.
- Upscale when needed. You say you have 4.7 Tb of imagery, how big is 
the target audience? Will they be viewing the entire image set up to the 
highest detail or will there be a limited "Area of interest"? I would 
say that it is pointless to create a infrastructure capable of holding 
the highest level of detail given the amount of disk space when only a 
hundred users will be active..
- Find an investor

In my opinion, you are on top of imagery that is of invaluable worth to 
your audience. Why would they want to cut on the infrastructure costs?

Sounds a bit like; we want a money-transport truck, but we would not 
want to invest in armoring it and giving it an engine to outrun any bandits.

I think someone needs to do some good presales work here and set up an 
excellent business case.

Good luck!

Kind regards,

Milo van der Linden

karsten vennemann wrote:
> Hi All,
>  
> I am seeking some advice/ alternative ideas about the following 
> project I am working on...
> I have been tasked with researching the best and fastest options 
> serving huge raster datasets on a web map using OpenLayers o the fly 
> (using all Open Source software). We want to serve the US NAIP Aerials 
> in 1m resolution (which are a total of about 4.7 TB of MrSid/Jp2 data) 
> on a interactive  web map as an optional map background. The are using 
> MapServer to serve our other  (vector) data such as roads, rivers etc 
> as WMS  to overlay onto this. Of course there are many ways to go 
> about this but one of the things we determined early on is that 
> MapServer is too slow to serve compressed imagery such as the native 
> MrSid Jp2 imagery on the fly for our needs. Thus, one option would be 
> to spare MapServer from having to decompress the images. We can then 
> also avoid having to convert them to tiff and adding overviews (using 
> gdaladdo for example). This would also "blow up" the total data volume 
> to something about 60 TB ...
> Thus, we are in the process of researching options on how to serve the 
> compressed data as fast as possible "on the fly" and without the need 
> for caching them on disk (that means no TileCache nor GeoWebCache 
> should be used because that also would involve having to set up huge 
> storage spaces ...
> One option I came about was using IIpimage server and this would then 
> involve converting the MrSid all to Jp2 format. One advantage is that 
> OpenLayers 2.9 already has natively the Zoomify layer support so that 
> we can easily add the images coming out of IIPImage Server Zoomify + 
> JPEG2000 server http://help.oldmapsonline.org/jpeg2000/
> I also found that another option is the Djatoka Jpeg 2000 Image Server 
> http://sourceforge.net/apps/mediawiki/djatoka/index.php?title=Main_Page 
> and the J2K Tiler Renderer: 
> http://dltj.org/article/introducing-j2ktilerenderer/.
> None of the above seem to enable output as WMS (correct me if I'm 
> wrong). One draw back is that all of those above are using the Kakadu 
> library which is great but not free for commercial use.
> I also wanted to research how the use of this new proxy server 
> http://mapproxy.org/ could improve our speed in combination with e.g. 
> IIP Image server...
>  
> Anybody has experiences with any of the above or comments ?
> Any input what you think would be the fastest option to serve 
> the compressed US NAIP onto a web map on the fly (without caching 
> tiles on disk) ?
>  
> Cheers
> Karsten
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