implementing an ogc (open geospatial …...implementing an ogc (open geospatial consortium) web...

“Implementing an OGC (Open Geospatial Consortium)

Web Processing Service in a WebGIS

Framework to analyze satellite data”

Grazia Caradonna*, Antonio Novelli,

Eufemia Tarantino, Benedetto Figorito, Umberto Fratino

*DICATECH - Politecnico di Bari, e-mail: [email protected]

IssuesDesertification is one of the most alarming processes of environmentaldegradation and it affects more than 25% of the Italian territory;

52% of the Italian territory is under risk of desertification, mainly in theSouthern regions;

Representing and finding maps at different geographical scalesshowing changes of degradation over large areas.

‟Implementing an OGC Web Processing Service in a WebGIS Framework to analyze satellite data”

Grazia Caradonna* , Antonio Novelli, Eufemia Tarantino, Benedetto Figorito, Umberto Fratino

ObjectivesIdentifying remote sensing datasets and methods to control thedesertification progress over large areas;

Creating a geodatabase with selected satellite sensors datasets;

Implementing an INSPIRE compliant WebGIS for disseminatinggeospatial raster and shape data.



The study area • The study area is Apulia and it

is characterized by:

• a landscape that changesconsiderably from season toseason;

• a lot of different vegetationspecies;

• Mediterranean heterogeneousclimate with strong inter-annual variability and amarked annual seasonality.



The datasets

9 Land Cover/Land Use (LULC) maps

from LANDSAT data over the Taranto

area (1986-2011)



NDVI maps from SPOT VGT time

series for the period 1999-2013

over the Apulia region.

Two data sources were used for populating the geodatabase and implementing the WebGIS

Image-processing

Landsat data were freely selected through the USGS EROS

web site (http://glovis.usgs.gov/) choosing the Level 1 terrain

corrected (L1T) format.

Then they were preliminary processed to improve the final

results of classification and subsequently used as input for the

Artificial Neural Network Classifier to obtain LULC maps.



Image-processing

SPOT VGT – NDVI time series data were selected

through the VITO Earth Observation Product Catalogue

(http://www.vito-eodata.be).

S10 VEGETATION Products are ten day global syntheses related

to all spectral bands (SWIR, NIR, RED, BLUE).

The NDVI auxiliary data were geometrically corrected to the

UTM-WGS’84 reference system



WebGIS Implementation

Two WebGIS prototypes were compared preliminary in order to

choose the best FOSS software suites :

1.Mapserver-Pmapper-Apache;

2.Geoserver- Openlayers – GeoEXT – PostgreSQL/PostGIS.





Comparison of two WebGISprototypes

Main differences between MapServer and GeoServer

MAPSERVER GEOSERVER

Based on Common Gateway Interface(CGI) technology

Based on JEE (Java Enterprise Edition)

Released under MIT-style license Released under GNU license

Developed in the 90s Developed in 2001

Written in C Mostly written in Java

Not provided with a Web Administration Interface

Provided with a Web Administration Interface

Not supporting WFS - Transactional Supporting WFS-Transactional

The first WebGIS prototype consists of four different free components:

1. UNM MapServer (version 6.4.1);

2. The WebMapping Framework –Pmapper;

3. Apache 2.2.22 webserver;

4. A browser.



WebGIS Implementation – 1st prototype



WebGIS Implementation – 1st prototype

The second WebGIS prototype consists of five different free components:

1. Geoserver 2.8.1, as an open source server for sharing geospatial data;

2. Openlayers 3.13.1, a pure JavaScript library for displaying map data in most

modern web browsers, with no server-side dependencies;

3. GeoExt 1.0;

4. PostgreSQL with geographical extension PostGIS;

5. A browser.



WebGIS Implementation – 2nd prototype



WebGIS Implementation – 2nd prototype

Validation and Speed Tests



MAPSERVER-

Pmapper

GEOSERVER -

OpenLayers

DATA ARCHIVING FILE SYSTEM (a few layers) POSTGRE SQL

MANAGEMENT OF SLD (STYLE) LOW HIGH

WMS SERVICES VISUALIZATION LOW HIGH

CUSTOMIZABLE INTERFACE MEDIUM HIGH

VECTOR (shapefile), RASTER

DOWNLOAD BASED ON QUERY

RISULTS

HIGH HIGH

USER FRIENDLY HIGH HIGH

VECTOR (shapefile) and RASTER

MANAGEMENT

HIGH

MEDIUM

(needs DB geographic

extension Geo-Json)

WEB PROCESSING SERVICE (WPS) NOT ALLOWED HIGH



Future developments

Implementing fully interactive systems in order to

extract raster information processed on the WEB

(i.e. quantitative interpretation of satellite data or 3D

modelling and query of multi-scale territorial objects),

testing further SW suites (i.e. QGis Server).



Thanks for Your Attention

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