maps4finland 28.8.2012, pekka sarkola
Post on 29-Nov-2014
1.434 Views
Preview:
DESCRIPTION
TRANSCRIPT
Understanding and processing geodata with Quantum GIS
Pekka Sarkola Gispo Oy
Gispo Oy We help customers to take advantage of the FOSS4G
(Free and Open Source So;ware for Geospa=al) so;ware and open data.
We support the development and u=lisa=on of open source so;ware and open data.
GIS in 5 minutes
GIS = Geographic Informa?on System
Data representa?on • Representa?on of real objects • Abstrac?on to – Discrete objects, like house – Con?nuous fields, like rainfall amount or eleva?on
• ”60-‐80% of all informa=on has loca=on” • Can only physical, real objects has loca?on? – Email – Money in bank account
Geographic informa?on data • Raster – Image
• Vector – Point – Polyline – Polygon
+ ANributes: name, id, type…
Collect
Model
Analyse Visualise
Share
What’s not GIS? • CAD – Computer-‐aided Drawning – Be aware about: DXF, DWG, …
• Google Maps – Points-‐on-‐the-‐map
Map projec?ons • Always distor?on of – Area – Shape – Direc?on – Bearing – Distance – Scale
Coordinate systems • You use already defined coordinate systems – …or do your own coordinate system
• Roughly 2000 – 3000 different coordinate systems • Web Nerd Shortcut (WNS): – ”I just use GPS coordinates”
• GIS Expert Answer (GEA): – ”So, you will use WGS84. Like La?tude / Longitude. How do you calculate distance between two points?”
Map Projec?on • WNS: ”I will use Google Web Mercator on my data visualisa?on”
• GEA: ”Right:”
Geodata File formats
Geodata File Formats • WMS: ”I will use SVG/XML/KML in my app…” • GEA: ”As you want, but…” – Size of files: XML is preNy big – Features: KML includes presenta?on – Data inside SVG?
Using Quantum GIS
Why Quantum GIS? • Some?mes you have to: – View, analyze, convert, manipulate or do something else with your geodata
• Quantum GIS is easy to use, free open source sojware for Linux, Mac and Windows plakorms
• More info and download: – hNp://www.qgis.org/
Live-‐demo
Where I can learn more? • Open Knowledge Fes?val, 17.-‐22.9.2012 – Open Geodata Hackathon and all other Open * things – www.okfes?val.org
• Paikka?etomarkkinat, 6.-‐7.11.2012 – Annual GIS event in Finland – www.paikka?etomarkkinat.fi
Or just contact me!
Ques%ons? Thank you!
Presenta?on includes maps from: © Na?onal Land Survey of Finland, data extract 05/2012
posiki
top related