Topic 03 - Geographic representations & data models.pdf

GEOG 482 Topic 03 GEOG 482 2 Review some key concepts in GIS: Geographic phenomena & their representation GEOG 482 3 represent Source: Burroughs & McDonnell (2015) Principles of GIS, 3rd Ed. Oxford. GEOG 482 4 Real World Conceptual Model Data Model GEOG 482 5 Image source: ESRI (http://desktop.arcgi...

GEOG 482 Topic 03 GEOG 482 2 Review some key concepts in GIS: Geographic phenomena & their representation GEOG 482 3 represent Source: Burroughs & McDonnell (2015) Principles of GIS, 3rd Ed. Oxford. GEOG 482 4 Real World Conceptual Model Data Model GEOG 482 5 Image source: ESRI (http://desktop.arcgis.com/en/arcmap/latest/extensions/3d-analyst/discrete-and-continuous-data-in-3d-analyst.htm) GEOG 482 6 Source: E Pluribus Anthony, transferred to Wikimedia Commons by Kaveh (log), optimized by Andrew pmk. GEOG 482 7 GEOG 482 8 GEOG 482 9 GEOG 482 10 Image source: http://www.unesco.org/ GEOG 482 11 Review some key concepts in GIS: Geographic phenomena & their representation GEOG 482 12 discrete object Source: saylordotorg.github.io GEOG 482 13 arc ending point starting point nodes vertices polygons linear features https://xmswiki.com/wiki/GMS:Feature_Objects GEOG 482 14 qualitative properties spatial relationships qualitative Source: https://www.esri.com/news/arcnews/summer02articles/arcgis-brings-topology.html GEOG 482 15 Adjacency GEOG 482 Containment Source: Burroughs & McDonnell (2015) Principles of GIS, 3rd Ed. Oxford. Connectivity 16 GEOG 482 17 Image: Course Textbook (Chang, 2019) Figure 3.8 GEOG 482 18 GEOG 482 Image: Course Textbook (Chang, 2019) Figure 3.11 19 GEOG 482 20 GEOG 482 21 object-relational model GEOG 482 22 Image source: ESRI (http://desktop.arcgis.com/en/arcmap/latest/manage-data/raster-and-images/discrete-and-continuous-data.htm) GEOG 482 23 tesselation continuous field GEOG 482 24 continuous field Modified from Fig 3.8; Longley et al. (2005) GEOG 482 Mixed conifer Oak savannah Douglas fir Grassland 25 GEOG 482 26 GEOG 482 Image source: http://www.catalonia.org/cartografia/Clase_03/Raster_Vector.html 27 - example of standard cell-by-cell encoding GEOG 482 Image: Course Textbook (Chang, 2019) Figure 4.8 28 Binary run-length encoding: Quadtree encoding: Images: Course Textbook (Chang, 2019) Figures 4.9 & 4.10 GEOG 482 29 GEOG 482 30 Vector Raster Data Volume Usually smaller, but depends on density of vertices Usually larger, but depends on pixel size Spatial Resolution Variable, but precision usually not constrained Fixed; precision achieved with large data volumes Data Structures Generally complex, handle multiple attributes Simple by comparison, only one attribute per dataset Typical Data Sources Social data, environmental data Remote sensing images, digital elevation models Common Applications Urban, economic, administrative Resource management, environmental, remote sensing Review some key concepts in GIS: Geographic phenomena & their representation Vector and raster data models GEOG 482 32 the central concept https://izismile.com/2015/08/26/spectacular_night_time_images _of_planet_earth_25_pics.html GEOG 482 33 Viking 1 – 1976 Mars Global Surveyor – 1998 MGS – 2001 Perspective view using elevation data from laser altimeter GEOG 482 34 size extent representative fraction scale GEOG 482 broad-scale fine- 35 level of detail accurate change shrink or grow GEOG 482 Image: https://gis-university.com/qgis-tutorial-for-beginners-1-qgis-orientation/ 36 GEOG 482 37 grain size Image Source: https://www.jbarisk.com/news-blogs/dem-spatial-resolution-what-doesthis-mean-for-flood-modellers/ GEOG 482 38 Coloseum, Rome (1 m) GEOG 482 Colosseum, Rome (8 m) Images: fas.org/irp/imint/docs/rst/Sect6/Sect6_12.html 39 Image: Heywood et al. 2009. An Intro. to Geog. Info. Systems, 3rd Ed. Pearson. GEOG 482 40 © G.J. Hay, 2004 GEOG 482 41 Changing Scales 4 4x4 cells 9x9 cells narrow extent GEOG 482 Source: Gergel SE & Turner MG. 2002. Learning Landscape Ecology. Springer. 20x20 cells broad extent 42 Changing Scales GEOG 482 100 cells 400 cells coarse resolution fine (double) resolution Source: Gergel SE & Turner MG. 2002. Learning Landscape Ecology. Springer. 43 Changing Scales 100 cells fine resolution, narrow extent GEOG 482 Source: Gergel SE & Turner MG. 2002. Learning Landscape Ecology. Springer. 100 cells coarse resolution, broad extent 44 GEOG 482 45 GEOG 482 46 Field 2018; Pg. 273 Source:https://socratic.org/questions/how-would-you-create-a-sketchillustrating-the-difference-between-the-terms-accur. GEOG 482 47