Introduction To Geographic Information Systems (gis)

Introduction to Geographic Information Systems (GIS)

Definitions ❧ “…a system of hardware, software, and procedures designed to support the capture, management, manipulation, analysis, modeling, and display of spatially referenced data for solving complex planning & management problems” (Rhind, 1989)

Definitions ❧ “…a computer system capable of assembling, storing, amnipulating, and displaying geographically referenced information…” (USGS, 1997) ❧ “…a set of computer-based systems for managing geographic data and using those data to solve spatial problems” (Lo & Yeung, 2002)

Definitions ❧ a computer system that allows the analysis and display of data with a spatial component (Phillips, 2002)

Definitions ❧ data: collection of facts/figures ❧ information: data in useful form ❧ knowledge: what you have ❧ intelligence: what you use

Information System ❧ allows the transformation of data into information via: ● ● ● ●

structuring formatting conversion modeling

❧ GIS: transforms data with a spatial component

Geographic Data ❧ spatial data ❧ referenced to “geographic space” ●

coordinate system • grid • other

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projection source • land survey • GPS • aerial imagery

❧ represented at a “geographic scale”

Geographic Information Science ❧ approach to using GISystems ❧ what to do & how to do it

GIS History ❧ Table, page 6 ❧ 1960’s & 1970’s - mainframe computers ❧ 1980’s to mid 1990’s - mainframe & minicomputers ❧ mid 1990’s to present - PCs & workstations

GIS data ❧ types ● ● ●

geodetic control network: surface location topographic base: point elevation graphical overlays: thematic data

❧ representation ● ● ●

vector: point, lines, polygons raster: grid cells surface

❧ metadata ● ●

information about the data key when sharing data

Point objects ❧ Locate by ordinal or ratio classification ● ●

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Implies quantitative attribute table Implies the selection of natural or arbitrary “break points” Use descriptive statistics to define boundaries • Mean, range, quartiles • Choose boundaries of significance

❧ E.G. Housing Value ● ●

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May have actual value recorded Divide into classes based on “affordability” or arbitrarily divide <$50,000; 51-100,000; 101,000-150,000, etc.

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Atlanta Banks Highway Routes Atlanta City Boundary County Boundaries

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Atlanta Banks by Deposits 87000 - 26825000 # 26825001 - 78484000 78484001 - 198631000 # # 198631001 - 495078000 # 495078001 - 2455763000 Highway Routes Atlanta City Boundary County Boundaries

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ZIP COUNT 30303 30305 30306 30308 30309 30310 30311 30312 30313 30314 30315 30316 30318 30319 30324 30326 30327 30331 30336 30342 30354

19 15 2 5 13 5 5 1 1 1 3 2 9 1 9 5 5 3 2 8 2

SUM_DEPOSIT 7234647000.0000 727136000.0000 56777000.0000 133581000.0000 352739000.0000 94454000.0000 55251000.0000 6401000.0000 37488000.0000 22904000.0000 78293000.0000 25640000.0000 176093000.0000 2769000.0000 305719000.0000 138933000.0000 219641000.0000 23082000.0000 51181000.0000 253185000.0000 52969000.0000

Use Summarize by Zones to Create "Density" Measure

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Atlanta Banks by Deposits Highway Routes Total Deposits by Zip 2769000 - 37488000 37488000 - 138933000 138933000 - 352739000 352739000 - 727136000 727136000 - 7234647000 Atlanta City Boundary

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Contiguity (after DeMers)

Contiguous region

Fragmented region

Perforated region

GIS technology ❧ hardware ●

organization • intranet: servers & client computer stations • PCs • internet

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considerations • processing power • file size (very large) • data access

GIS technology ❧ software ● ●

proprietary open standard

❧ companies ●

ESRI • ArcInfo & ArcView • ArcGIS

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Intergraph MapInfo

Application of GIS ❧ table - p 12 ❧ academic ❧ business ❧ government ❧ industry ❧ military

Users of GIS ❧ Specialist: includes programmers, designers, developers ❧ General Users: planners, scientists, administrators (us) ❧ Viewers: everyone (our “clients”)