Open geo data - technical issue
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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
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
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
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
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
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!!!