1. Faculty of Engineering Technology Building and Construction Sciences 1 EA141 Module 7 Geographic Information Systems GIS

2. 2 7.1 Information Systems collection of raw data processed to produce useful information Steps observation collection processing (analysis) results decisions e.g. test marks

3. 3 7.2 Geographic Information Systems geographic data = location (x,y,z,t) of: people places things all info in a GIS must be geographically refererenced temporal referencing much more difficult! processing = spatial analysis

4. 4 7.2 GIS vs. IS e.g. where to locate a new donut shop? I.S. … how many donut shops there are in Hamilton G.I.S. … draw me a map showing location of all donut shops in Hamilton GIS uses "spatial analysis" to produce a "smart map" most things we do in GIS could be done with paper maps (dumb maps)… but GIS makes it a lot easier time = $$$ … GIS makes new analyses feasible

5. 5 7.3 GIS and Surveying GIS  new data acquisition GIS relies on accurate data Surveying = new data acquisition other fields of Geomatics also contribute: GPS photogrammetry remote sensing

6. 6 7.4 What's it made of? GIS = hardware (computer, printer, etc.) software (MapInfo, ArcInfo, ArcView) data approx. $$cost$$ breakdown: hardware 10-20% software 10-20% data 60-80%  data acquisition  data entry  data scrubbing

7. 7 7.5 Spatial Data all natural or man-made features lines or symbols on maps images on photos "spatial object" = digital representation of real- world "entity" dimensionality… 0-D = (x,y,z) = "point data" 1-D = set of point data = "line data" 2-D = closed sets of lines = "area data" 3-D = "volume data"

8. 8 7.5 Spatial Data - Dimensionality 0-D = (x,y,z) = "point data" = position only e.g. manhole traffic light well donut shop 1-D = set of point data = "line data" e.g. roads sewers property lines stream

9. 9 7.5 Spatial Data - Dimensionality 2-D = closed sets of lines = "area data" e.g., building footprint park wooded area land zoned "commercial" 3-D = "volume data" e.g., gravel quarry cut/fill area oil/gas deposit

10. 10 7.5 NON-Spatial Data a.k.a. "attribute data" = any other characteristics that pertain to an entity e.g. ownership soil type age of structure material e.g. water well spatial data = point data = 0-D = location non-spatial data = owner's name, drill date, depth, etc.

11. 11 7.6 Data Models what data needs to be included in the GIS? depends on end-uses depends on budget $$$ two types of data models Raster (dumb) = 0-D Vector (smart) = 1-D to 3-D

12. 12 7.7 Topology branch of math describing relationships between spatial objects topological relation may be: connectivity (connected to another object)  directionality (before or after another object) adjacency (beside another object) nestedness (inside another object)

13. 13 7.8 Analysis - Buffering common analytical function of GISs area around an object think of AutoCAD "OFFSET" command point buffer = area around a point line buffer = area left & right of a line polygon buffer = area around area

14. 14 7.8 Other Analyses adjacency e.g. find neighbouring properties connectivity e.g. find connected watermains, streets to evaluate emergency preparedness overlay MOST COMMON ANALYSIS e.g. show all properties:  with no vegetation  slope < 5%  on clay soil  < 15 min from a donut shop

15. 15 7.9 GIS & GPS GPS gives current location of mobile things GIS knows locations of fixed features GIS + GPS tells me: what route will minimize time application to emergency vehicles, police best route from where I am to a donut shop when visiting a new city "the only limit is our imagination"…