From Geographic Information to GIS
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From Geographic Information to GIS

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From Geographic Information to GIS From Geographic Information to GIS Presentation Transcript

  • From Geographic Information to GISGetting the Map into the computerPart I: Data Collection Arnaud Vandecasteele Memorial Univ. of Newfoundland, Canada 3/02/2013
  • OutlineIntroduction 1 - Data Collection 2 – Conversion process 3 – Data Storage 4 – Data AnalysisConclusion 2/36 Introduction
  • ObjectivesMethods to acquire GIS data, particularly via the GPSMethods to create new GIS dataProcesses to edit existing GIS dataTypes and sources of error potentially associated with GIS data 3/36 Introduction
  • GeoSpatial Revolution 4/36 Introduction
  • From physical reality to computer How to represent reality ? Fonseca et al., 2002 5/36 Introduction
  • From physical reality to computer REAL WORLD Source: http://www.uvm.edu/~gis/ 1 2 3 4 5 6 7 8 9 1012345678910 GRID RASTER VECTOR 6/36 Introduction
  • Data Collection Process Data Conversion Data DataCollection Process Storage Analysis .Gpx 7/36 Data Collection Conversion Process Data Storage Data Analysis
  • Geodata collectingTwo main types of data capture: ● Primary data sources (direct measurement) collected in digital format specifically for use in GIS (e.g., GPX, Satellites Images) ● Secondary sources (indirect derivation) need to be converted into a suitable digital for use in a GIS project (e.g., CSV, Excel, etc.) 8/36Data Collection Conversion Process Data Storage Data Analysis
  • ● Primary data sources (direct measurement) collected in digital format specifically for use in GIS (e.g., GPX, Satellites Image) Raster Data Capture Vector Data Capture (Remote Sensing)You are not directly measuring GPS, LiDAR the object, but is reflectance 9/36Data Collection Conversion Process Data Storage Data Analysis
  • Geodata collecting - GPS ● Primary data sources (direct measurement) collected in digital format specifically for use in GIS (e.g., GPS, Satellites Image) Example of a GPX file<?xml version="1.0" encoding="UTF-8"?><gpx version="1.0"> <name>Example gpx</name> <wpt lat="46.57638889" lon="8.89263889"> <ele>2372</ele>Example of <name>Example Points</name>A waypoint </wpt> <trk><name>Example gpx</name><number>1</number><trkseg> <trkpt lat="46.57608" lon="8.89241"><ele>2376</ele><time>2007-10-14T10:09:57Z</time></trkpt> <trkpt lat="46.57619" lon="8.89252"><ele>2375</ele><time>2007-10-14T10:10:52Z</time></trkpt>Example of <trkpt lat="46.57641" lon="8.89266"><ele>2372</ele><time>2007-10-14T10:12:39Z</time></trkpt> a track </trkseg></trk></gpx> 10/36 Data Collection Conversion Process Data Storage Data Analysis
  • What is GPS The Global Positioning System (GPS) is a constellation of satellites that is used to calculate your position. 11/36Data Collection Conversion Process Data Storage Data Analysis
  • How GPS works ? 1 20130203-1045-3001 1 Each satellite continuouslybroadcasts timing information 12/36 Data Collection Conversion Process Data Storage Data Analysis
  • How GPS works ? 1 20130203-1045-3001 1 Each satellite continuouslybroadcasts timing information 2 20130203-1045-3148 2 A GPS receiver measuresdistance using the travel timeof radio signals 13/36 Data Collection Conversion Process Data Storage Data Analysis
  • How GPS works ? 1 Each satellite continuouslybroadcasts timing information 3 2 A GPS receiver measuresdistance using the travel timeof radio signals 3 We are somewhere on the circlewhere these two spheres intersect 14/36 Data Collection Conversion Process Data Storage Data Analysis
  • How GPS works ? Trilateration (Triangulation) 1 Each satellite continuouslybroadcasts timing information 2 A GPS receiver measuresdistance using the travel time 4of radio signals 3 We are somewhere on the circlewhere these two spheres intersect 4 The receiver calculates the distanceto each satellite and trilateratesits own position 15/36 Data Collection Conversion Process Data Storage Data Analysis
  • Are GPS perfect ?Accuracy – sources of errors ● Ionospheric effects ± 5 meters ● Tropospheric effects ± 0.5 meter ● Ephemeris errors ± 2.5 meters ● Satellite clock errors ± 2 meters ● Multipath distortion ± 1 meter ● Numerical errors ± 1 meter 16/36 Data Collection Conversion Process Data Storage Data Analysis
  • Geodata conversion Data Conversion Data DataCollection Process Storage Analysis .Gpx 17/36 Data Collection Conversion Process Data Storage Data Analysis
  • Geodata conversion process<?xml version="1.0" encoding="UTF-8"?><gpx version="1.0"> <name>Example gpx</name> .Gpx <wpt lat="46.57638889" lon="8.89263889"> <ele>2372</ele> <name>Example Points</name> </wpt> <trk><name>Example gpx</name><number>1</number><trkseg> <trkpt lat="46.57608" lon="8.89241"><ele>2376</ele><time>2007-10-14T10:09:57Z</time></trkpt> <trkpt lat="46.57619" lon="8.89252"><ele>2375</ele><time>2007-10-14T10:10:52Z</time></trkpt> <trkpt lat="46.57641" lon="8.89266"><ele>2372</ele><time>2007-10-14T10:12:39Z</time></trkpt> </trkseg></trk></gpx> Point Line (track) .Gis 18/36 Data Collection Conversion Process Data Storage Data Analysis
  • Geodata conversion process GPSBabel @ http://www.gpsbabel.org Converts data between popular GPS Extensive data manipulation abilities Multi-platform (e.g., Windows, Mac, Linux) User Interface 19/36Data Collection Conversion Process Data Storage Data Analysis
  • Geodata Storage Data Conversion Data DataCollection Process Storage Analysis .Gpx 20/36 Data Collection Conversion Process Data Storage Data Analysis
  • Geodata storingProprietary Systems Oracle Spatial, Microsoft SQL ServerOpen Source PostgreSQL/Gis, MySQL, SQLiteService Based Google BigTable, Amazon SimpleDB 21/36 Data Collection Conversion Process Data Storage Data Analysis
  • Geodata storing PostGis @ http://postgis.refractions.net/ Project started in 2001 Based on Postgresql Many GeoFunctions (e.g., Buffer, Intersects) Geometric, Geographic and Raster data MySql Spatial @ http://dev.mysql.com/ Integrated into MySQL since 4.1 Geometric data (plan) No projection Few spatial function SpatialLite @ http://www.gaia-gis.it/spatialite/ Based on SQL Lite Minimal weight (250 ko) Many GeoFunctions (e.g., Buffer, Intersects) User Interface 22/36Data Collection Conversion Process Data Storage Data Analysis
  • How GeoData are storing ?GPX <trk><name>Example gpx</name><number>1</number><trkseg> <trkpt lat="46.57608" lon="8.89241"><ele>2376</ele><time>2007-10-14T10:09:57Z</time></trkpt> <trkpt lat="46.57619" lon="8.89252"><ele>2375</ele><time>2007-10-14T10:10:52Z</time></trkpt> <trkpt lat="46.57641" lon="8.89266"><ele>2372</ele><time>2007-10-14T10:12:39Z</time></trkpt> </trkseg></trk> WKT WKB Well Know Text Well Know Binaryele time geom_wkt ele time geom_wkb1 2007-10- LINESTRING(46.5760 1 2007-10- 010200002031BF0D0 14T10:09:57Z 8 8.89241,46.57619 14T10:09:57Z 00900000085EB5140 8.89252,46.57641 E...1F6285CDFAED56 8.89266) 7C185EB5118DF664 E41 23/36 Data Collection Conversion Process Data Storage Data Analysis
  • Data Conversion Data DataCollection Process Storage Analysis .Gpx 24/36 Data Collection Conversion Process Data Storage Data Analysis
  • Geodata visualisation - desktop QGIS @ http://www.qgis.org/ArcGis@ http://www.esri.com 25/36Data Collection Conversion Process Data Storage Data Analysis
  • Geodata visualisation - internet OpenLayers @ http://www.openlayers.org/ArcGis@ http://www.arcgis.com 26/36 Data Collection Conversion Process Data Storage Data Analysis
  • Quality insurancePositional accuracyDefined as the closeness of locational information to the true positionAttribute accuracyDefined as the closeness of attribute values to their true valueLogical consistencyRefers to the internal consistency of the data structure,particularly applies to topological consistencyCompletenessConcerns the degree to which the data exhausts the universe of possible itemsLineageA record of the data sources and of the operations which created the database 27/36 Conclusion
  • OSGEO-Live Looking for software? OSGEO-Live http://live.osgeo.org/ 28/36 Conclusion
  • To go further Geographic Information Systems and Science Paul A. Longley, Mike Goodchild, David J. Maguire, David W. Rhind 2010 A primer of GISFundamental Geographic and cartographic concepts Francis Harvey 2008 29/36 Conclusion
  • Have Fun with Geography Lets GeoPlay 30/36 Conclusion
  • GeocachingCan I Geo Play ?Geocaching (http://www.geocaching.com/)Outdoor recreational activity in which the participantsuse a GPS to hide and seek containers,called "geocaches" or "caches", anywhere in the world 31/36 Conclusion
  • Geocaching 32/36 Conclusion
  • OpenStreetMapCan I Geo Play ?OpenStreetMap (http://www.openstreetmap.org/)Outdoor recreational activity in which the participantscreate free geographic data for the world. 33/36
  • OpenStreetMapOpenStreetMap @ http://www.openstreetmap.org/ 34/36 Conclusion
  • Have Fun with GeographyActivity 1 - Find the Geocache located at : Nad 83 → Lat 47°34.334, Lon -52°43.858Activity 2 - Record OpenStreetMap GeoData Thanks to the weather 35/36
  • EquipmentGPS Mobile App Walking Paper 36/36