Open geo data - technical issue

Open Geo Data

Some technical aspects

Maurizio Napolitano [email protected]

The gis wikification

paper here http://tinyurl.com/gis-jolie

Spatial is Special?

NO!● Data are data● The Geographical

Information Systems are very well defined

YES!● Maps are the

power● A map is a complex

database but simple to understand

http://justinholman.com/2012/03/20/spatial-is-indeed-special/Spatial is Indeed Special…but GIS Software Skills will Soon be Obsolete

The GIS recipe

● Projections● Data models● Analysis● Rendering

Projections

source: http://xkcd.com/977/

Ex. Cilindric projection

(X,Y)

Datum

http://www.gisetelerilevamento.com/2010/04/superfici-di-riferimento-e-coordinate/

Ex.World Geodetic System 84

geoid

Universal Traverse Mercator

source: USGS

UTM Zone

http://upload.wikimedia.org/wikipedia/commons/e/ed/Utm-zones.jpg

The most used in web devel.● EPSG:4326 - WGS84

– Degree (lat/long)– WGS84

● EPSG:900913 – Google Mercator– Meters – WGS84– World without polos

● Digit version of the word GOOGLE

EPSG?

ex European Petroleum Survey Grouphttp://www.epsg.org/

Resources

http://spatialreference.org

● 4362 EPSG references

● 447 ESRI references

● 2380 IAU2000 references

http://trac.osgeo.org/proj/

Cartographic Projections library

Data Models

Discrete Data

Vectors with attributesPoints

Lines

Polygons

Continuous Data

MatrixEx.

Digital Elevations Models

Solar Power cells

Orthophotos

GEOREFENCED

Example Raster

http://en.wikipedia.org/wiki/Esri_grid

DTM gray

DTM elevation

Example Vector

Points

Lines

Overlay

Query

Network Analysis

Graphs

Solar radiation

Precipitation

Nice … but Open Data?

Yes!Licenses & Formats & Protocols

Our friends

Only if he speaks also about open data

Open Formats● Vectors

– ESRI Shapefile– GML– GeoJSON– KML

● Raster– Ascii Grid– GeoTiff–

Eg. ESRI Shape

● Standard de facto● 3 (4) files with the same name and

different extension

filename.shp → geometry

filename.shx → index

filename.dbf → table

(filename.prj → projection)

Geo Web Services● WMS

– Web Map Service

● WFS

– Web Feature Service

● WCS

– Web Coverage Service

● WPS

– Web Processing Service

● TMS

– Tile Map Service

● CSW

– Catalog Service for the Web

TMS

An Example of Open Geo Data

Service

http://data.wien.gv.at/

Clients

Where are the data?

http://earthexplorer.usgs.gov/http://publicdata.eu

… and more more ...

OpenStreetMapOpen Community Data

~ … but for the maps ...born in 2004

HOW?

People and vehicles of OpenStreetMap(slide by Niccolo Rigacci – http://www.rigacci.org - CC-BY-SA-NC)

WHO

Tools

http://wiki.openstreetmap.org/wiki/Map_Features

Geometries and attributes

Collect the data

Trace the data

with the walking papers

http://walkingpapers.org/print.php?id=d6rzwc3d

Improve the data collected

help thematic maps

http://wheelmap.org

http://www.openstreetmap.org/?lat=44.493944&lon=11.343526&zoom=18&layers=A

Official

http://wiki.openstreetmap.org/wiki/List_of_OSM_based_Services

Tappa “Herning-Herning” – http://www.gazzetta.it/Speciali/Giroditalia/2012/it/tappa.shtml?t=01&lang=it

Giro d'Italia(1/2)

Giro d'Italia (2/2)

Maurizio [email protected]

Blog:http://de.straba.us

Twitternapo

Slideshttp://www.slideshare.net/napo

Thanks!!!