[postgis-devel] trying PostGIS online

Marc Jansen jansen at terrestris.de
Wed Dec 16 06:03:23 PST 2009 

Hi Nicklas,

find my answers inline:


Nicklas Avén wrote:
> Hallo Mark
>  
> Great :-)
>  
> Absolutely, we should try to get something useful out of this together.

Maybe we simply chat when the book is published? What do you think?

>  
> What is producing your maps? Mapserver, geoserver?

I have a background world-WMS served by I-don't-know... it's external, I 
simply use the service. The spatial data from a query is being rendered 
by the browser as vectorgraphics (OpenLayers allows you to display e.g. 
WKT-Strings as vector data, SVG, VML etc.).

>  
> I have one longterm-thought about this (seen from my situation as a 
> novice hacker trying my best :-)) , give me a few lines to explain:
> I think PostGIS gets too samll attention at least in this part of the 
> world. Here I have focused on two reasons I think is obvious.
> 1)   as I wrote in last post, people doesn't at once see the 
> possibility to use spatial sql-queris for analyses, they just use the 
> spatial database for storing. An online testarea to send everybody 
> little curious could maybe help some of that.

Yes, maybe.

> 2)  I think it is a weakness that almost no webhotels can offer a 
> PostGIS functionality (together with mapserver or Geoserver) and I 
> think one problem is to be able to manage your spatial data on a 
> webhotel. Other data you can manage with phppgAdmin in postgresql. Of 
> cource you can manage spatial data to like that but you will easily 
> get a feeling that you don't have control if you can't easily see your 
> data. So I think maybe the webhotels would be more intrested if there 
> were a web user interface to the spatial data.

webhotels are webhosters, right ? :-) I am not an expert in that field, 
bnut would guess that only few of them offer a PostgreSQL-database, and 
even fewer one with PostGIS preinstalled... at least within the minimal 
package that includes a database.

As for the simple preview of stored spatial data from with phppgadmin, I 
am pretty sure I remember a plugin that did that. Not sure what it was 
called though, sorry

>  
> So my plan is to get this tutorial site (not nessesary from my initial 
> approach) running, hoping for people to contribute in the development 
> of the site. That will have a positive effect on PostGIS during this 
> development process and maybe it will give ideas and encourage someone 
> to implement it in for example phppgAdmin.
>  
> It's not illegal to be naive :-)

I don't think you are naive. Publishing your ideas (or solutions to 
problems you happen to stumble upon) is the core of OSS, isn't it? Who 
knows if someone will jump on the train? No one will join you if you 
don't publish... so go on, release early and often!

Regards,
Marc

>  
> /Nicklas
>  
>  
>
> 2009-12-16 Marc Jansen wrote:
>
> Hi Nicklas, Hi list,
> >
> >I love the idea of trying SQLs in a browser and instantly get a spatial
> >result! Actually I have built an OpenLayers [1] client for an upcoming
> >book of mine [2] that does this. Furthermore I wanted to transform that
> >special bit of code (the interactive terminal and the OpenLayers client)
> >into an OpenSource application. Actally I recently submitted a talk to
> >the german conference FOSSGIS [3] -- organized by the local german
> >chapter FOSSGIS [4] of the OSGEO -- that wants to discuss the project
> >and further possible development. The talk is not yet accepted.
> >
> >I took a slightly different appproach (Mainly because the initiual
> >application was being developed for the book):
> >
> > * One opens the address of the application in the browser
> > * You see a world map (an external WMS) in a minimal OpenLayers-Client
> > * below the Map there is a terminal where you can enter more or less
> > any SQL
> > * Upon submission of the form data is sent via AJAX to aserver side
> > script
> > * that script does some checking and finally queries the database
> > and gioves the result back to the client
> > * if the result of the query is a geometry, it gets displayed on
> > the map as a vector geometry instantly
> > * if the result is a meta-infomation (eg ST_Area, etc.) That Info
> > is displayed in the client.
> > * There are some restrictions currently (allowed projections, number
> > of returned records and the like)
> >
> >I have working code for all of the above, but have to wait to publish
> >the details until the book is finally there (that would be February
> >2010, hopefully). All the code in the book will be released under the
> >BSD license.
> >
> >I see a big potential for an application like that (or the one you
> >describe), so please contact me on- or offlist if you see any chance on
> >working together on something like this.
> >
> >Best regards,
> >Marc
> >
> >PS: Please excuse that I start a new thread because I couldn't reply
> >directly to the original email.
> >
> >[1] http://openlayers.org
> >[2] german only:
> >http://www.amazon.de/OpenLayers-Webentwicklung-dynamischen-Karten-Geodaten/dp/3937514929/ref=sr_1_1?ie=UTF8&s=books&qid=1260946463&sr=8-1
> >[3] http://www.fossgis.de/konferenz/wiki/Main_Page
> >[4] http://www.fossgis.de/
> >
> >
> >
> >
> >Original email from Nicklas:
> >Hallo
> >
> >I have had an idea about a site where people can try and test postgis
> >online.
> >Working with spatial data in db-environment I think a lot of people
> >seems like abstract and maybe suspect and
> >their picture of analyse spatial data is often tightly connected to some
> >Arc-products.
> >
> >So, now I have come up with something as a start.
> >
> >The basic idea is that a sql-string generates a view or a table that
> >mapserver produces a transparent gif-image from.
> >The idea of working with transparent images is that you can produce many
> >(three in the application of today) images that will be put on top of
> >each other. The first defines the extent and the others will be showed
> >on top.
> >
> > From this concept I continued and found a way of easily producing
> >tutorials.
> >The idea is that a tutorial (defined by some objects in a html-file)
> >controls 4 objects in the window (see attached picture):
> >* the text in a describing text -holder to the right in the screen
> >* the text in the sql-string text area, so the user can just click a
> >button to see the result, modify it and try again
> >* Background map, One of the maps in the dataabse, shown "as is" in full
> >extent or in extent defined by Map1
> >* An image, it is possible to, instead of the map give the url to an
> >image. Might b convinient for showing something in the tutorial
> >
> > From this tools it should be easy, bith to present all the PostGIS
> >functions and explain new things like Geography-type or wkt-raster.
> >
> >I think it could give many sql-gurus an aha-experiense to see the
> >possibilities of analysing spatial data with sql.
> >
> >I have bought postgisonline.org for the purpose. (Thought it was best
> >buying it before discussing it in public :-)
> >There is also other suggestions but I don't know if that was an option
> >for sure or just maybe . I have no opinion in that question.
> >Does it sound interesting?
> >I would like it all to be open source. Do I haev to but some special
> >text in the files. Do I/we risk anything if I just dump it all to this
> >list?
> >
> >about the attached pictures:
> >* the artistic example is Reginas example in documentation to
> >st_longestline, buffered with 1, 2 respective 5 units on top of eachother
> >* picture.jpeg is the page 2 of a tutorial shoving what it looks like.
> >Not very fancy, but I'm little alergic to heavy fanciness on the web.
> > But should maybe be little more good looking with colors and so on.
> >
> >Regards
> >Nicklas
> >_______________________________________________
> >postgis-devel mailing list
> >postgis-devel at postgis.refractions.net
> >http://postgis.refractions.net/mailman/listinfo/postgis-devel
> >
> >
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  Dipl.-Geogr. Marc Jansen
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