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PRIN 2007

prin2007

Link to general project information:

http://cercauniversita.cineca.it/php5/prin/cerca.php?codice=2007XAN53L

Latest development in GIS context put attention to Web-Gis Applications.
In the latest years the two areas Gis and Web-Gis goes to have a common development, due to the increase of request of remote services and delivered services.
The research is oriented to propose urban and suburban 3D models, so that they could be joint by a so called “Geo-Services”; this implies the placement of this data on geographically distributed servers so that once connected in network, provide services that integrate each other, building so called “Cooperative and Territorial Data Infrastructure”.
At the moment this area is characterised by expensive cost, reduced standardization, absence of computational instruments, lack of unified mechanism to access 3D information.
Actually most of cartographic standardised products are characterised by a bidimensional structure; recently some models of cartographic structure have been proposed, based on universal standards, like GML3 language, recently defined as standard by OGC.
Particularly, GIANT3D model (Geographical Interoperable Advanced Numerical Topological 3-Dimensional Model) developed in the research PRIN 2004 “Strutture evolute della cartografia numerica per i GIS e l’ambiente WEB”(Evolute structure of numerical cartography for Gis and Web Area)- Authors: Ammoscato A., Corsale R., Scianna A. - began as proposal of a National Standard to structurate a 3D Numerical cartography for GIS, in which are assumed the statements of “Commissione Geodetica Italiana” (Italian Geodesic Committee) and “Intesa-Gis”, which model is not “full-3D”.
Actually geographical data could be structured like above-mentioned model through an application of Autocad, with storage of the data into a proprietary database, which allows the export of geographical information together with their attributes in GML3 format.
The research would to inquire into the use of open source database, to store three-dimensional geographical data and answer to queries using internet browsers.

The idea that inspired the proposition of research is to find ways to allocate, in a spatial database implemented through PostgreSQL and PostGis, all geometrical and topological informations of the just implemented model .
So is necessary to get by a proprietary not standard structure (used in previous experiment) to a data structure organised and allocated to a Geo-DB whit standardised modality.
One of the possible results of this research could be providing 3D-Gis information, with high semantic content for browsing,with simplified view and query, trough a Web-Gis Based Platform.

The objectives are summarized in research of ways to store the geometrical-topological full 3D model in the spatial database, the study of methods for querying the spatial database, and the study and implementation of a three-dimensional navigation module that uses the webgis-server mentioned above.
In order to achieve the objective of the allocation of data on PostGIS, is necessary to perform the following steps:
- study on PostGIS functions and potentialities;
- possible implementations of new features to enable the allocation of information, consistent with the GIANT3D model;
- building of a software module that allows you to import data, structured according to the schema files GIANT3D, in PostGIS;
- creation of a software module, similar to the one currently written and tested by the research, that interacts directly with a PostGIS database within the working Autocad;
Once the allocation of spatial data in a open source database has been realized, there is the problem of gaining access to such data by internet; this requires the definition of a Web-GIS structure that allow to query directly on the database, with output in GML3.
We will check the suitability of that language for real-time visualization of three-dimensional data sets on the web, through the use or subsequent development of an Internet browser for GML3. The starting point is a browser already implemented from research group using open source library, able to browse the data stored on local support and structured in GML3 according with the GIANT3D scheme.
The communication between the browser and server data must be based on WFS protocol, a client-server architecture that provides access to data contained in geo-database through a webservice.
The client requests data to webservice, that analyses the request, extracts data from the database as required and sends them to the client in an XML message, structured in GML3 format.


Python function 1

Python function 2

Python function 3

Link to the 3D Web Feature Service application

After the selection of previous link, wait the browser download the java applet, then once the user interface has been dowload:

  • select the window with the label GetObject WFS3D;
  • fill the URL field with the string:

http://147.163.1.55:8090/WFS3D/Service

  • press the OK button at the end of the page;

wait the query returns the answer and after the GML3 answer, click on View button;

Yuo will be redirected to the Browser windows in wich you can navigate a 3D GIANT model made available through WFS 3D.

Double-click on GIANT3DModel to browse geographical objects of the model.

Università degli Studi di Palermo Home page del Consiglio Nazionale delle Ricerche

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Contatti:

email: gislab.geomatica@unipa.it