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Re: [udig-devel] Seeking more direction from the uDIG community
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I'm thinking I'm going to take a look at it too :).
Jesse
On 10-Jan-07, at 1:34 PM, Paul Ramsey wrote:
Murray,
Sorry, that rant was more particularly directed at Jesse, who sits
about 12 feet from Kevin, and therefore knows how to find him. :)
Kevin can send you his PostGIS plugin for JUMP, which you can
modify for your needs.
Paul
Murray Richardson wrote:
Ok, thanks.
Who is Kevin and how can I contact him?
Murray
Paul Ramsey wrote:
What you need is a "SQLDataStore" that operates like Kevin's CWB
PostGIS plugin for JUMP. If you don't know what it is, please
ask him to demo it for you, it is the perfect combination of
flexibility and leverage of the GIS infrastructure. The
SQLDataStore would take in a SQL string, and database connection
information and try to run it. If the result set returned
without error, and included a geometry, it would map it. If it
returned an error, it would verbosely report it.
Paul
Jody Garnett wrote:
Question for Cory;
Can we let the PostGisGeoResource resolve to a the JDBC
connection pool? That way Mr Richardson can just start coding
with JDBC (which he appears to be comfortable with).
Jody
Hello Community,
Thanks for previous help you've offered. I could use a bit
more direction if possible to determine whether I should carry
on with uDIG for a small project I am working on. I'm finding
the uDIG development learning curve to be a bit steep so far.
I've spent the last few days looking at uDIG (e.g. plugin
tutorial and all the other online resources) and I am trying to
figure out the simplest way to make use of powerful postgreSQL/
postGIS capabilities. Previously I was concerned with
constructing spatial queries on massive point data sets. These
processes are easy if I use a standard postgreSQL interface
like psql or pgAdmin. It seems like it should be a fairly
simple task to construct plugins within uDIG that make use of
these and other RDBMS capabilities through JDBC (if they don't
already exist somewhere). I read an entry on Cory Horner's
community page about extending uDIG functionality to
incorporate better RDBMS capabilities. I am most definitely
interested in this because I am always faced with problems
where this type of capability would be an asset.
To give you an idea of the type of functionality I am
interested in, considering the following two examples:
(1) I am constantly using GIS and RDBMS capabilities separately
(loosely coupled fashion)for information management in the
field of hydrology. For example - I need to summarize the joint
probability distribution of land-use and soil types to
determine an average (lumped) runoff coefficient for nested
watersheds (since runoff is a function of landuse and
underlying soil properties, among other things). I do this by
exporting the polygon intersection of a soils layer, land-use
layer and watershed layer to a RDBMS. Then I use lookup tables
to determine coefficients for individual landuse-soil
combinations and use an aggregate query to determine the mean
value for each watershed. It is nice to then join the mean
value back to the watershed layer and display this in a map. I
also use the RDBMS to do reporting of the individual
intersected polygons by watershed. This type of analysis and
reporting is standard in flood risk assessment and could be
very easily streamlined with a tool like uDIG and postgreSQL.
(2) Storing and accessing spatial-temporal hydrology data is an
emerging area of interest (consider the ESRI ArcHydro framework
if you're familiar with it) and an interesting direction for
Open Source GIS. For example, I would like to be able to store
decades worth of hourly streamflow data for numerous gauged
weirs within a postgreSQL DB and have this linked to a uDIG
application that allows me to extract the streamflow data by
(e.g.) clicking on a point station and entering a date. The
query result could be just exported to a text file for now.
This capability would open the door to a whole range of
interesting spatial-temporal hydrology applications (e.g.
recession analysis, climate and streamflow data interpolation,
hydrologic model parameterization).
Based on these two particular examples, could someone perhaps
direct me on how to proceed to develop a very simple proof of
concept for enhanced RDBMS capabilities within a GIS
environment? Consider example 1 for instance - can I create a
uDIG operation that is accessed by right-clicking on 3
highlighted layers (like the difference operation that is
available when two layers are selected). For my purposes I
would like these to be postGIS layers. The operation could
then execute the postGIS intersection procedure, the attribute
join and the aggregate function all within the postgreSQL
service, and then map the results back to the watershed layer
for display in uDIG?
I know this is a fairly specific question, but what it boils
down to is, how do I access postGIS spatial operations as well
as general postgreSQL RDBMS functionality and non-spatial
tables within the uDIG environment?
Thanks in advance for any help. This project is for a small
Open Source/Open Access Student Experience program grant I am
working on through University of Toronto that involves
developing a proof-of-concept idea and some educational
tutorials using postgreSQL/postGIS. I would like to eventually
be able to post the results on my own uDIG community page if
things go well. I think this type of work could help open up
uDIG capabilites to the slightly less technical users like
myself (e.g. GIS and basic programming/RDBMS skills experience,
but still need lots of examples and explicit documentation to
follow!).
Look forward to hearing back from someone - hope it's not too
much to ask over a mailing list!
_______________________________________________
User-friendly Desktop Internet GIS (uDig)
http://udig.refractions.net
http://lists.refractions.net/mailman/listinfo/udig-devel
_______________________________________________
User-friendly Desktop Internet GIS (uDig)
http://udig.refractions.net
http://lists.refractions.net/mailman/listinfo/udig-devel
_______________________________________________
User-friendly Desktop Internet GIS (uDig)
http://udig.refractions.net
http://lists.refractions.net/mailman/listinfo/udig-devel
_______________________________________________
User-friendly Desktop Internet GIS (uDig)
http://udig.refractions.net
http://lists.refractions.net/mailman/listinfo/udig-devel