[OSGeo-Discuss] OS Spatial environment 'sizing' + Image Management

Tue Feb 19 18:15:03 PST 2008

IMO:

Hi Randy,

Thank you for your informative post. It has given me a lot to follow up on 
and think about.

I can see an immediate need that this type of solution could well be used 
for. I like it.

I suspect that in many larger corporate types of environments, it could 
well be used effectively for 'pilot' and 'pre-production' type tasks. 

For 'production' type environments, there would be issues of integrating 
an external service hosting spatial data with internal services hosting 
corporate aspatial data sources and applications.

with regards to storing imagery in a database:

<rant>       (and not directed at you)

I've also seen a lot of reports suggesting that image management should be 
file based.

My personal preference is to use a database if possible, so that I can 
take advantage of corporate data management facilities, backups, point in 
time restores etc.

I've managed 70 GB orthophoto mosaics in ArcSDE / Oracle before with 
minimal problems. I found performance and response times to be comparable 
with other image web server options on the market that use file based 
solutions for storing data.

Ideally, I'm looking to manage state wide mosaics with a consistant look 
and feel that can be treated as a single 'layer' by client GIS / Remote 
Sensing applications (data integrity issues allowing). 

One potential use is 'best available' data mosaics could undergo regular 
updates as more imagery is flown or captured. A database makes it easier 
to manage and deliver such data.

My definition of 'imagery' goes beyond aerial photographs and includes 
multi or hyper-spectral imagery; various geophysics data sources such as 
aeromagnetics, gravity, radiometrics; radar data etc.

Typically this data is required for digital image analysis purposes using 
a remote sensing application, so the integrity of 'the numbers' that make 
up the image is very important.

Many of today's image based solutions use a (lossy) wavelet compression 
that can corrupt the integrity of 'the numbers' describing the radiometric 
data in the image.

When we consider the big picture issues facing us today, such as Climate 
Change, I think that it is important to protect our definitive image 
libraries from such corruption as they will be invaluable sources of data 
for future multi-temporal analysis.

That said, if the end use is just for a picture, then a wavelet 
compression is a good option. Just protect the source data for future use.

</rant> 

So, does anyone know of a good open source spatial solution for storing 
and accessing (multi and hyperspectral) imagery in a database?    ;-)

WMS 1.3 and WCS are showing promise for serving imagery, including multi 
and hyperspectral data.

Bruce Bannerman

discuss-bounces at lists.osgeo.org wrote on 20/02/2008 10:09:28 AM:

> Hi Ivan,
> 
>    The most common advice I've seen says to leave raster out of the DB.
> Of course footprints and meta data could be there, but you would want to
> point Geoserver coverage to the image/image pyramid url somewhere in the
> directory hierarchy.
> 
> Brent has a nice writeup here:
> http://docs.codehaus.org/display/GEOSDOC/Load+NASA+Blue+Marble+Data
> 
> In an AWS sense my idea is to Java proxy the Geoserver Coverage Data URL 
to
> S3 buckets and park the imagery over on the S3 side to take advantage of
> stability and replication. Performance, though, might not be as good as 
a
> local directory. Maybe a one time cache to a local directory would work
> better.
> 
> Note: Amazon doesn't charge for inside AWS data transfers.
> 
> So in theory:
>   PostGIS holds the footprint geometry + metadata
>   EC2 Geoserver WFS handles footprint queries into an Svg/Xaml client, 
just
> stick it on top of something like JPL BMNG. Once a user picks a coverage
> switch to the Geoserver WMS/WCS service for zooming around in the 
selected
> image pyramid
>   S3 buckets contain the tiffs, pyramids ...
>   EC2 Geoserver handles WMS/WCS service
>   EC2 proxy pulls the imagery from the S3 side as needed
> 
> Sorry I haven't had time to try this so it is just theoretical. Of 
course
> you can go traditional and just keep the coverage imagery files on the 
local
> instance avoiding the S3 proxy idea. The reason I don't like that idea 
is
> the imagery has to be loaded with every instance creation while an S3
> approach would need only one copy.
> 
> 
> randy
> 
> -----Original Message-----
> From: Lucena, Ivan [mailto:ivan.lucena at pmldnet.com] 
> Sent: Tuesday, February 19, 2008 2:59 PM
> To: rkgeorge at cadmaps.com; OSGeo Discussions
> Subject: Re: [OSGeo-Discuss] OS Spatial environment 'sizing'
> 
> Hi Randy, Bruce,
> 
> That is a nice piece of advise Randy. I am sorry to intrude the 
> conversation but I would like to ask how that "heavy raster" 
> manipulation would be treated by PostgreSQL/PostGIS, managed or 
unmanaged?
> 
> Best regards,
> 
> Ivan
> 
> Randy George wrote:
> > Hi Bruce,
> > 
> > 
> > 
> >                 On the "scale relatively quickly" front, you should 
look 
> > at Amazon's EC2/S3 services. I've recently worked with it and find it 
an 
> > attractive platform for scaling http://www.cadmaps.com/gisblog
> > 
> > 
> > 
> > The stack I like is Ubuntu+Java+ Postgresql/PostGIS + Apache2 mod_jk 
> > Tomcat + Geoserver + custom SVG or XAML clients run out of Tomcat
> > 
> > 
> > 
> >                 If you use the larger instances the cost is higher but 

> > it sounds like you plan on some heavy raster services (WMS,WCS) and 
lots 
> > of memory will help.
> > 
> > Small EC2 instance provides $0.10/hr:
> > 
> > 1.7 GB of memory, 1 EC2 Compute Unit (1 virtual core with 1 EC2 
Compute 
> > Unit), 160 GB of instance storage, 32-bit platform
> > 
> > 
> > 
> > Large EC2 instances provide $0.40/hr:
> > 
> > 7.5 GB of memory, 4 EC2 Compute Units (2 virtual cores with 2 EC2 
> > Compute Units each), 850 GB of instance storage, 64-bit platform
> > 
> > 
> > 
> > Extra large EC2 instances $0.80/hr:
> > 
> > 15 GB of memory, 8 EC2 Compute Units (4 virtual cores with 2 EC2 
Compute 
> > Units each), 1690 GB of instance storage, 64-bit platform
> > 
> > 
> > 
> > Note: that the instances do not need to be permanent. Some people 
> > (WeoGeo) have been using a couple of failover small instances and then 

> > starting new large instances for specific requirements. The idea is to 

> > start and stop instances as required rather than having ongoing 
> > infrastructure costs. It only takes a minute or so to start an ec2 
> > instance. If you are running a corporate service there may be parts of 

> > the day with very little use so you just schedule your heavy duty 
> > instances for peak times. If you can connect your raster to S3 buckets 

> > rather than instance storage you have built in replicated backup.
> > 
> > 
> > 
> > I know that Java JAI can easily eat up memory and is core to Geoserver 

> > WMS/WCS so you probably want to look at large memory footprint for any 

> > platform with lots of raster service. I'm partial to Geoserver because 

> > of its Java foundation.  I think I would try to keep the Apache2 
mod_jk 
> > Tomcat Geoserver on a separate server instance from PostGIS. This 
might 
> > avoid problems for instance startup since your database would need to 
be 
> > loaded separately. The instance ami resides in a 10G partition the 
> > balance of data will probably reside on a /mnt partition separate from 

> > ec2-run-instances. You may be able to avoid datadir problems by adding 

> > something like Elastra to the mix. Elastra beta is a wrapper for 
> > PostgreSql that puts the datadir on S3 rather than local to an 
instance. 
> > I suppose they still keep indices(GIST et al) on the local instance.
> > 
> > (I still think it an interesting exercise to see what could be done 
> > connecting PostGIS to AWS SimpleDB services.)
> > 
> > 
> > 
> > So thinking out loud here is a possible architecture-
> > 
> >     Basic permanent setup
> > 
> > put raster in S3 - this may require some customization of Geoserver,
> > 
> > build a datadir in a PostGIS and backup to S3
> > 
> > create a private ami for Postgresql/PostGIS
> > 
> > create a private ami for the load balancer instance
> > 
> > create a private ami with your service stack for both a small and 
large 
> > instance for flexibility,
> > 
> >    Startup services
> > 
> > start a balancer instance
> > 
> > point your DNS CNAME to this balancer instance
> > 
> > start a PostGis instance (you could have more than one if necessary 
but 
> > it would be easier to just scale to a larger instance type if the load 

> > demands it)
> > 
> > have a scripted download from an S3 BU to your PostGIS datadir (I'm 
> > assuming a relatively static data resource)
> > 
> >    Variable services
> > 
> > start service stack instance and connect to PostGIS
> > 
> > update balancer to see new instance - this could be tricky
> > 
> > repeat previous  two steps as needed
> > 
> > at night scale back - cron scaling for a known cycle or use a 
controller 
> > like weoceo to detect and respond to load fluctuation
> > 
> > 
> > 
> > By the way the public AWS ami with the best resources that I have 
found 
> > is Ubuntu 7.10 Gutsy. The debian dependency tools are much easier to 
use 
> > and the resources are plentiful.
> > 
> > 
> > 
> > I've been toying with using an AWS stack adapted for serving some 
larger 
> > Postgis vector sets such as fully connected census demographic data 
and 
> > block polygons here in US. The idea would be to populate the data 
> > directly from the census SF* and TIGER with a background Java bot. 
There 
> > are some potentially novel 3D viewing approaches possible with xaml. 
> > Anyway lots of fun to have access to virtual systems like this.
> > 
> > 
> > 
> > As you can see I'm excited anyway.
> > 
> > 
> > 
> > randy
> > 
> > 
> > 
> > 
> > 
> > *From:* discuss-bounces at lists.osgeo.org 
> > [mailto:discuss-bounces at lists.osgeo.org] *On Behalf Of 
> > *Bruce.Bannerman at dpi.vic.gov.au
> > *Sent:* Monday, February 18, 2008 6:35 PM
> > *To:* OSGeo Discussions
> > *Subject:* [OSGeo-Discuss] OS Spatial environment 'sizing'
> > 
> > 
> > 
> > 
> > IMO:
> > 
> > 
> > Hello everyone,
> > 
> > I'm trying to get a feel for server 'sizing' for a **hypothetical** 
> > Corporate environment to support OS Spatial apps.
> > 
> > 
> > 
> > Assume that:
> > 
> > - this is a dedicated environment to allow the use of OS Spatial 
> > applications to serve Corporate OGC Services.
> > 
> > - the applications of interest are GeoServer, Deegree, GeoNetwork, 
> > MapServer, MapGuide and Postgres/PostGIS.
> > 
> > - the environment may need to scale relatively quickly.
> > 
> > - it will be required to serve in the vicinty of 5 to 10 TB of data 
> > initially (WMS, WFS, WCS).
> > 
> > 
> > 
> > Can anyone shed some light on the following questions please?
> > 
> > - I'm assuming a Linux installation (SLES, Redhat or Debian) or 
possibly 
> > Intel Solaris. Has anyone experienced any issues in these (or other) 
> > environments that they'd like to share?
> > 
> > - Are there any recommendations as to dedicated network bandwidth that 

> > should be allocated?
> > 
> > - Has anyone done any work with load balancing and would like to share 

> > their experiences?
> > 
> > - Of the above OS Spatial products, which ones could co-exist on the 
> > same server (excluding Postgres/PostGIS)?
> > 
> > 
> > Any thoughts are appreciated.
> > 
> > 
> > Bruce Bannerman
> > Australia
> > 
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