Re: [postgis] Development Roadmap

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Re: [postgis] Development Roadmap

Nicolas Ribot-4
Hello everybody,

In the attempt to provide a global solution for delivering
geographic maps and information on the internet, we
have developed a solution based on MapServer to generate
interactive maps in browsers.

This solution uses a lightweight java applet and Javascript
objects on the client to display the map.
The question of storing geographic data in a relationnal-object
database, and using these objects directly to
produce maps was obviously crucial, but not very
straightforward: Existing solutions (Oracle spatial, DB2
spatial cartridge, Esri SDE, etc...) are expensive, difficult
to use, and not very efficient.

We decided to use a SQL92-compliant DB schema to store
geographic objects coordinates in the database, and to
dump data into shapefiles on-the-fly (performance was good
enough for our applications, with small geographic
objects).

After having seen the great potential of PostGis, and tested
very briefly the performance, we have immediatly
decided to use PostGis for the storage of geographic data:
(the test consisted in loading (shp2pgsql), and displaying with
MapServer all the french cities (36646
polygons). The performance was really astonishing, even when
building dynamic spatial query with PostGIS/OpenGIS
operators).

We would like to provide a framework based on OpenSource code
to ease the handling of geographic data and their
use on the internet:

    - An HTML application to display maps, navigate, select
layers, query objects, etc... (done)

    - A DB schema to store MapServer MapFiles in the database.
(done)

    - A tool (php) to parse and load existing mapFiles into the
DB schema, and to dump the schema into a MapFile
(done)

    - A geographic data loader interface to shp2pgsql
(html/php) to populate the DB with existing data from
files (currently shapefile, but later other geographic formats
by adding a conversion tool before shp2pgsql (FME
for ex.))
This interface allows to browse for raster files and registers
them in the Database, in a raster table storing
spatial extent, raster name, acquisition date, description, and
file path to the raster.
(done, very first version...)

    - A layout manager (html/php), allowing to choose which
data will compose the map, and the graphic layout
associated with the data (=> generation of a new mapFile) (NOT
done)

    - An application generator (html/php) to compose the
end-user html page presenting the map. (not done)
    - We would also like to provide, in the future, interfaces
allowing to make geographic queries directly on
the internet.

This project is just beginning: there is no internet demo yet
available.

We also have some experience about OpenGIS Simple Feature
Specifications gained when developping an
OpenGIS-compliant spatial cartridge for DB2 and Oracle (SRText
format, metadata schema, spatial operators).

As requested for PostGIS 0.6, we can also provide Spatial
Reference Text (SRTEXT) for European projections and
UTM zones:
    UTM zone 5 to 60, North and South
    WGS 84 Lat Long
    Lambert conformal conic (french projection),
    Swiss Projection on 1937 and 1903 datums
    Gauss-Kruger zone 1 to 5 on Bessel and Krasovsky ellipsoids
(german projections)

Regards, and congratulations for PostGIS extension !

Nicolas Ribot - [hidden email]
Jerome Gasperi - [hidden email]




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Re: [postgis] Development Roadmap

Paul Ramsey-2
Nicolas,
It sounds like you have big plans! Are these open source projects?

>     - A layout manager (html/php), allowing to choose which
> data will compose the map, and the graphic layout
> associated with the data (=> generation of a new mapFile) (NOT
> done)

DM Solutions should be releasing an opensource web-based Mapserver
configuration tool in the next couple months. You might want to wait and
see how that fits with your plans...

> As requested for PostGIS 0.6, we can also provide Spatial
> Reference Text (SRTEXT) for European projections and
> UTM zones:
>     UTM zone 5 to 60, North and South
>     WGS 84 Lat Long
>     Lambert conformal conic (french projection),
>     Swiss Projection on 1937 and 1903 datums
>     Gauss-Kruger zone 1 to 5 on Bessel and Krasovsky ellipsoids
> (german projections)

Thanks. SRTEXT will become more important now that we're putting the OGC
metadata into the database. Would a srtext.sql file of all the known
SRTEXT forms be useful to people? There is a file which has all the EPSG
projections in SRTEXT already, and we could add others as they become
known/used.

> Regards, and congratulations for PostGIS extension !

Thanks, please keep us up-to-date w/ what you're doing.

Paul

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Re: [postgis] Development Roadmap

Lyndon Zimmermann
In reply to this post by Nicolas Ribot-4
Nicholas,

one element I noted was missing was handling of metadata.  XML appears
to be taking the lead, through the ability to parse and present the
metadata in different ways.  Is this part of your project, and if so,
what standards?

Lyndon Z

Nicolas Ribot wrote:
>
> Hello everybody,
>
> In the attempt to provide a global solution for delivering
> geographic maps and information on the internet, we
> have developed a solution based on MapServer to generate
> interactive maps in browsers.
>

--
Lyndon Zimmermann
BE (Mech Adelaide) Grad Dip Bus Admin (UniSA)

"Bioenergy Atlas for Australia" Co-ordinator
University of Adelaide Agronomy and Farming Systems
C/- GISCA, 4th floor, 10 Pulteney St, Adelaide 5005
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Fax (GISCA) +61-8-8303 3498 email [hidden email]
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Re: [postgis] Development Roadmap

Nicolas Ribot-4
In reply to this post by Paul Ramsey-2


Paul Ramsey wrote:

> Nicolas,
> It sounds like you have big plans! Are these open source projects?

Yes, indeed,  this projects is ambitious. Maybe a little bit too ambitious for 2 developpers...
All these projects will be open source.

>
> DM Solutions should be releasing an opensource web-based Mapserver
> configuration tool in the next couple months. You might want to wait and
> see how that fits with your plans...

Yes. I saw this prototype yesterday. It is very impressive and seems to fits our needs fully.
So we will concentrate our developement on the other tasks.

> Thanks. SRTEXT will become more important now that we're putting the OGC
> metadata into the database. Would a srtext.sql file of all the known
> SRTEXT forms be useful to people? There is a file which has all the EPSG
> projections in SRTEXT already, and we could add others as they become
> known/used.

I think such a srtext.sql file would be useful.

Regards.
Nicolas



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Re: [postgis] Development Roadmap

Nicolas Ribot-4
In reply to this post by Lyndon Zimmermann
> Nicholas,
>
> one element I noted was missing was handling of metadata.  XML appears
> to be taking the lead, through the ability to parse and present the
> metadata in different ways.  Is this part of your project, and if so,
> what standards?
>
> Lyndon Z
>

You're right Lyndon.
For the moment, the tools we plan lack the metada handling.
We will think about XML to present them, and study the existing solutions,
especially OpenGIS Web Map Server to see how they handle metadata.

Nicolas


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