Maps4Finland 28.8.2012, Pekka Sarkola

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Pekka Sarkola (Gispo Oy): Understanding and processing geo data with QGIS

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Maps4Finland 28.8.2012, Pekka Sarkola

  1. 1. Understanding  and  processing   geodata  with  Quantum  GIS   Pekka  Sarkola     Gispo  Oy  
  2. 2. 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.  
  3. 3. GIS  in  5  minutes  GIS  =  Geographic  Informa?on  System  
  4. 4. 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  
  5. 5. Geographic  informa?on  data  •  Raster   –  Image  •  Vector   –  Point   +  ANributes:     –  Polyline   name,  id,  type…   –  Polygon  
  6. 6. Collect  Share   Model   Visualise   Analyse  
  7. 7. What’s  not  GIS?  •  CAD   –  Computer-­‐aided  Drawning   –  Be  aware  about:  DXF,  DWG,  …  •  Google  Maps   –  Points-­‐on-­‐the-­‐map  
  8. 8. Map  projec?ons  •  Always  distor?on  of   –  Area   –  Shape   –  Direc?on   –  Bearing   –  Distance   –  Scale  
  9. 9. 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?”  
  10. 10. Map  Projec?on  •  WNS:  ”I  will  use  Google  Web  Mercator  on  my  data   visualisa?on”  •  GEA:  ”Right:”  
  11. 11. Geodata  File  formats  
  12. 12. 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?  
  13. 13. Using  Quantum  GIS  
  14. 14. 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/  
  15. 15. Live-­‐demo  
  16. 16. 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  
  17. 17. Or  just  contact  me!   Ques%ons?   Thank  you!   posiki  Presenta?on  includes  maps  from:    ©  Na?onal  Land  Survey  of  Finland,  data  extract  05/2012  

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