The document discusses different topics related to open location data including file formats, coordinate systems, map projections, and georeferencing. It explains that there are roughly 2000-3000 coordinate systems and around 300 commonly used GIS file formats. The document also provides details on different geographic coordinate systems including WGS84 and transformations between coordinate systems.

1. Shapefiles, WGS84 and other odd terms
Workshop on Open Location Data
Pekka Sarkola

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History
Finland first time on the map by Jacob Ziegler (1532)

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File formats

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Combination
 Roughly 2000 – 3000 coordinate systems
 Around 300 commonly used GIS file formats

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Coordinate systems
Polar Coordinate system
Cartesian coordinate system Geographic coordinate system

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Coordinate systems – no problems...
 What is origin?
 What is direction?
 What is unit of measurement?
 You have choices:
 Thousands of different coordinate systems
 Good ones and bad ones
 Old vs new
 Local vs global

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Geographic Coordinate Systems
 Latitude (leveys), longitude (pituus) and ellipsoid height
 Common datums / geodetic systems
 WGS 84, 72, 64, and 60
 ETRS89
 NAD83 / NAD27 : USA
 OSGB36: GB
 ED50: European Datum
 Hayford International 1924: base of

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Demo

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Map projections: Basic challenge
 Your paper map and your computer screen is flat
 World is not!

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Map projections
 Always distortion of
 Area
 Shape
 Direction
 Bearing
 Distance
 Scale

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Universal Transverse Mercator (UTM)

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Finnish Coordinate Systems
 Kartastokoordinaattijärjestelmä (KKJ)
 Old one, from 1970’s
 Map projection:
 Transverse mercator, 6 zones
 EUREF-FIN
 New, based on ETRS89
 Several map projections
 ETRS-TM35FIN
 ETRS-TM21, 27, 33
 ETRS-GK19-31

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Web mercator

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Georeferencing, geotagging,
 Georeferencing
 ”To georeference something means to define its existence in
physical space”, Wikipedia
 Especially for aerial and satellite imagery
 Geotagging
 Add coordinates to single item, like picture taken with mobile
phone

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Geocoding
• Transform address / place name to coordinates
D2.8.I.5 INSPIRE Data Specification on Addresses – Guidelines

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Questions?