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Beginner’s GIS

Beginner’s GIS. Biodiversity Informatics Training Workshop June 2012. Outline. What is GIS GIS & Map Fundamentals Spatial Data Types Data Formats Software DEMO/Exercises. What is GIS?. GIS = G eographic I nformation S ystem(s)

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Beginner’s GIS

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  1. Beginner’s GIS Biodiversity Informatics Training Workshop June 2012

  2. Outline • What is GIS • GIS & Map Fundamentals • Spatial Data Types • Data Formats • Software • DEMO/Exercises

  3. What is GIS? GIS = Geographic Information System(s) GIS is a collection of computer hardware, software, and geographic data for capturing, managing, analyzing, and displaying all forms of geographically referenced information. Environmental Systems Research Institute (ESRI), 2007

  4. What is GIS? An “image” with attribute information

  5. What is GIS? Tool to make complex patterns simple

  6. What is GIS? Environment for integrating diverse data

  7. Overview of spatial data Raster and vector data collide

  8. Overview of spatial data

  9. Vector data Points, lines, and polygons

  10. Vector data • Shapefiles are common vector format of GIS data • Shapefiles consist of 3 main components: • *.shp – main file stores geometry • *.shx – index of geometry • *.dbf – database of attributes

  11. Vector data • Shapefiles may also have: • *.prj – plain text file of projection • *.sbn and *.sbx – spatial index of features • *.atx – index of attributes • *.shp.xml – metadata

  12. Raster Data Resolution e.g. 4 x 4 km

  13. In practice, resolution and extent tend to be inversely related Extent Resolution General data issue: spatial scale Spatial scale has two elements: resolution and extent Decrease in resolution Increase in extent

  14. Raster Data Resolution= cell size

  15. 15 KM pixel

  16. 7.5 km per pixel

  17. 4.5 km per pixel

  18. 1 km per pixel

  19. Raster Data Raster data - interpolation

  20. Raster Data Raster data - interpolation Inverse distance weighting Kriging Polynomials Or Spline

  21. Raster Data Raster data - interpolation Polynomials Or Spline Inverse distance weighting Kriging • Uses a mathematical function to create a minimize overall surface curvature • Sample points pass through surface • Best for variables like T • Statistical method that fits a function to a radius of points, assuming a spatial correlation in distance or directionality • Interpolated surface do not pass through sample sites • Many different types • Using linear-weighted set of samples (greater the distance, the less influence on output raster value) • Good for dense sampling

  22. Raster Data Raster data - interpolation

  23. Environmental Data: conversion to raster Weather station records (vector point data) WorldClim Method: Hijmans et al. 2005 Interpolated raster climate surfaces (grid)

  24. Gridded Climate Models are not just for climatologists any more…

  25. Prism vs. Worldclim

  26. Prism vs. Worldclim

  27. Raster Data Raster data - remote sensing

  28. Raster Data Raster data - remote sensing Ned Horning, Center for Biodiversity and Conservation, AMNH

  29. Raster Data Raster data - remote sensing Passive: Natural EM radiation e.g. Infrared, Aerial light photography Active: Sensor EM radiation e.g. RADAR, LIDAR

  30. Raster Data Common formats: • ESRI ASCII (.asc) • ESRI Grid • Geotiffs (.tif) • Any raster file can be used as a GIS grid Also: • MrSID • netCDF • BIL

  31. Raster Data What’s in an ESRI grid? • dblbnd.adf • hdr.adf • sta.adf • vat.adf • w001001.adf –> actual raster data • w001001x.adf • prj.adf (opt)

  32. Vector v. Raster Tradeoffs between the 2 types of data

  33. Vector v. Raster Tradeoffs between the 2 types of data

  34. Software

  35. ArcGIS • Commercial software, but ESRI Conservation Program grants support non-profits with free licenses • ArcGIS is a suite of applications: ArcMap, ArcCatalog, ArcTools • Lots of extensions and interacts well with python and R stats with an extension • Includes, web server, web services, online GIS, and freeware (ArcExplorer)

  36. DIVA-GIS • Free, not open source • Designed for niche modeling: Bioclim, Domain

  37. uantum GIS • Open source, • Functionality from plugins in C+ or python • Access to GRASS and R routines

  38. Some GIS Software Resources • DIVA-GIS • http://www.diva-gis.org/ • Quantum GIS • http://qgis.org/ • Free Geography Tools • http://freegeographytools.com/ • GISLounge • http://gislounge.com/ • FreeGIS.org • http://freegis.org/

  39. Some GIS Data Resources • Climate Data: • http://www.worldclim.org/ • http://www.prism.oregonstate.edu • Global Land Cover Facility • http://www.landcover.org/ • EarthExplorer (US DEM, LC) • http://edcsns17.cr.usgs.gov/NewEarthExplorer/ • USGS Seamless Viewer • http://seamless.usgs.gov/ • Global Administrative Boundaries • http://www.gadm.org

  40. Scale / Environmental Variable Dependencies Pearson and Dawson 2003 Global Ecology and Biogeography

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