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## What is a ...

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**What is a ...**G I S Geographic Information System**Abstraction**Printed Maps Real World**Abstraction**Representation Printed Maps Real World**Abstraction**Representation Printed Maps Real World Conversion Digital Model**Abstraction**Representation Printed Maps Real World Conversion Presentation Digital Model**Abstraction**Representation Printed Maps Real World Conversion Analysis Presentation Digital Model**Abstraction**Representation Printed Maps Real World Conversion Analysis Presentation Action Digital Model**Abstraction**Representation Printed Maps Real World Conversion Analysis Presentation Action Digital Model**Descriptive Data**Chris Buhi 1757 Millbrook Ln 28226 Y 2 Christian Carlson 1761 Millbrook Ln 28226 Y 1 Chris McGuire 1765 Millbrook Ln 28226 Y 2 Dale Loberger 1776 Millbrook Ln 28226 N 6 Donna Buccini 1780 Millbrook Ln 28226 Y 2 Doug Ruppel 1537 Sandberry Dr 28226 Y 1 Gary Waters 1541 Sandberry Dr 28226 Y 3 Holly Williams 1200 Yamasee Dr 28210 Y 4 Jim Wojcik 980 Harrowfield Rd 28226 N 1 Jo-Ann Brown 1812 Millbrook Ln 28226 N 2 Joe Rubisch 1090 Overhill Dr 28112 Y 4 Larry Young 1108 Kings Canyon Dr 28226 Y 3 Lee Ross 1605 Bosham Ln 28226 Y 2 Marcia Austin 1429 Quail Wood Dr 28226 Y 2 Mary Jo Fraley 1432 Quail Wood Dr 28226 Y 1 Mike Dyer 1430 Quail Wood Dr 28226 Y 3 Mike Rhoades 1332 Cameron Forest Dr 28173 Y 3 Mike Sweeney 1327 Red Hickory Ln 28173 Y 2 Paul Gallimore 1429 Buckeye Ct 28173 Y 2**Geographic Information**N 6 Donna Buccini 1780 Millbrook Ln Y 2 .ancaster Jo-Ann Bro 1812 Millbr Y 2 Millbrook Lane Christian Carlson 1761 Millbrook Ln Y 1 Chris McGuire 1765 Millbrook Ln Y**Spatial Representations**.ancaster POINTS POLYGON LINES Millbrook Lane ANNOTATION NODES**Geographic Representations**POLYGON:a closed area formed by one or more lines (eg. parcels, soil types, political boundaries, city limits, and census tracts) LINE: a feature defined by connecting a series of coordinates or through a geometric description (eg. streams, street centerlines, parcel surveys, water lines, and gas mains)**Geographic Representations**POINT: a feature defined by a single coordinate (eg. maintenance hole covers, well locations, light poles, eagle nests, survey monuments) NODES: features located at the intersection of two lines (eg. street intersections, pipe joins) ANNOTATION: a text string placed on a map as a graphic description (eg. street names, and parcel or index numbers)**Geographic**Representations Point Line Polygon Anno Node**Geographic**Representations Vector Point Line Polygon Anno Node Each of these geographic representations can be grouped into a category of VECTOR data**Geographic**Representations Vector Point Line Polygon Anno Node Point Attribute Table Line Attribute Table Polygon Attribute Table Node Attribute Table Text Attribute Table These features are then linked to user-defined attribute tables**Spatial Relationships(Topology)**Area Definition Connectivity Adjacency**Arc-Node Topology**2732 12 432 433 107 435 434 24 477 125 33 438 37 480 2641 41 478 2642**Arc-Node Topology**FNODE#TNODE#LPOLY#RPOLY#LENGTHPARCEL# 39 37 0 2641 540.12 477 48 37 2641 2642 297.45 478 39 48 2641 2651 140.33 479 37 41 0 2642 153.56 480 2732 12 432 433 107 435 434 24 477 125 33 438 37 480 2641 41 478 2642**Polygon-Arc Topology**FNODE#TNODE#LPOLY#RPOLY#LENGTHPARCEL# 39 37 0 2641 540.12 477 48 37 2641 2642 297.45 478 39 48 2641 2651 140.33 479 37 41 0 2642 153.56 480 2732 12 432 433 107 435 434 24 477 PARCEL#ARC LIST 2641 477, 478, 479 2642 478, 480, 481, 482 125 33 438 37 480 2641 41 478 2642**Regions & Routes**Regions**Regions & Routes**Regions**Regions & Routes**Regions**Regions & Routes**Regions Route Systems**Regions & Routes**Regions Route Systems**Geographic Representations**REGIONS: an extension of the polygon feature which can define overlapping and discontinuos areas (eg. barrier islands, chemical applications, and trade area studies) ROUTES: an extension of line features which permits dynamic definition of linear, or point, features as a segment of a line or spanning across multiple lines (eg. street pavement conditions, stream quality, and sewer pipeline breaks)**Table Relationships**AREAPERIMPARCEL#PARCEL-ID PIN -8654365 96432.5 10 0 65567.54 75343.2 2 2641 536274 43576.22 46512.9 3 2642 541280 46533.71 50264.2 4 2643 539291 2732 12 432 433 107 435 434 24 477 PINOWNER ADDRESS 536274 Christian Carlson 1761 Mi 541280 Chris Mguire 1765 Mi 539291 Dale Loberger 1767 Mi 125 33 438 37 480 2641 41 478 2642**Why Vector?**• maintains very accurate graphic representations of map features • maintains polygon data as a single attribute record • maintains discrete features for points, lines, polygons, nodes, and annotation • permits the combination of data layers while maintaining accurate graphic representation**Discrete Raster Representations**ORIGINAL VECTOR CELLS**ValueCountPavementCost**0 175 1 29 Y 125 Discrete Raster Representations**Continuous Raster Representations**ORIGINAL SAMPLE POINTS CELLS**NO TABLE ASSOCIATED WITH**CONTINUOUS GRID DATA Continuous Raster Representations**Geographic Representations**CELLS: a representation of geographic data based on rows and columns (eg. continuous surface data such as elevation or temperature, and categorical representations derived from vector data) PIXELS: a group of independent points with a color value but no other associated data (eg. scanned documents, orthophotography, satellite images)**Geographic**Representations Vector Cell Pixel Point Line Polygon Anno Node Point Attribute Table Line Attribute Table Polygon Attribute Table Node Attribute Table Text Attribute Table**Geographic**Representations Raster Vector Cell Pixel Point Line Polygon Anno Node Point Attribute Table Line Attribute Table Polygon Attribute Table Node Attribute Table Text Attribute Table A regular structure of rows and columns form RASTER data**Geographic**Representations Raster Vector Cell Pixel Point Line Polygon Anno Node Point Attribute Table Line Attribute Table Polygon Attribute Table Node Attribute Table Text Attribute Table Continuous Discrete Value Attribute Table Attributes can be associated with categorical cell groupings**Why Raster?**• permits the display of images • allows fast data layer combinations (raster overlays are accomplished through map algebra statements) • better suited for analysis of continous data or the interaction of discrete data with continous surfaces (examples include weighted distance models, hydrological models, and neighborhood analysis)**Why GIS?**Geometric Analysis Network Analysis GIS Data Model Cartographic Output Raster Analysis Modeling Interfaces Visualization**Geometric Analysis**Buffer: create an equidistant polygon around geographic features using a constant or attribute value Overlay: create a new data set by combining two or more data sets Query: perform graphic or tablular selection Proximity: determine distance between features of distinct data sets**Raster Analysis**Neighborhood Analysis: examine the effect of proximity of cells to their neighbors Surface Paths: calculate optimal path across a surface of “movement” costs Hydrological Functions: calculate flow across surfaces and determine watersheds, delineate and order streams, or model subsurface flow**Network Analysis**Optimal Path: calculate optimal path through a linear network modeling costs and present written directions Nearest Facility: locate nearest facility to a defined address or point Linear Allocations: determine “service areas” by allocating lines to facilities Routing Solutions: solve linear transportation problems such as best order routing (“traveling salesman”)**Cartographic Output**Thematic Shading: shade polygons based on attributes using vector or raster fill patterns including transparent backgrounds Automatic Text: intelligent text labeling and text overposting Hybrid Display and Plot: presentation of vector and raster data**Visualization**3D Display: display data in three dimensional space with control over user viewpoint Surface Drape: drape raster or vector data over a 3D surface View Calculation: determine line-of-sight or viewshed from any vantage point and elevation**Modeling Interfaces**Third Party Applications: access to the largest offering of third party applications for any GIS software**... a working definition**A computer system consisting of hardware and software that utilizes relational database technology and a topological data structure to allow the integration of raster and vector spatial data with tabular information for display, edit, query, analysis, combination, creation, maintenance, and management of geographic data sets in an environment that is customizable to meet the application needs of the users forming a powerful network of information that facilitates the sharing of data for better decision-making.**Functionality**Investment Professional GIS Desktop GIS Desktop Mapping Consumer Maps Bundled Maps