Working with Geographic Information

Systems

Nicholas Tancredi PUB 310 Summer

2014

What is GIS?“A geographic information system is a computer system for recording, managing, analyzing, and displaying geographic data” (O’Sullivan, Rassel, & Taliaferro, 2011).

GIS uses attribute data, which are nonspatial data that provide additional information about the geographic data.

GIS uses two types of data: Raster and Vector. “Raster data use individual cells to create an image. This data is used in satellite images, digital photography, and aerial views of land. Vector data use points, lines, and polygons to create images. Vector data display streets and roads, and vector polygons display areas with boundaries such as cities, counties, and other jurisdictions. Program managers in the public sector use vector data most often” (O’Sullivan, Rassel, & Taliaferro, 2011).

Selecting, Creating, and Using GIS DataCreating spatial data for GIS is a labor intensive process

and very expensive as well. This can present a problem for nonprofit and other nongovernmental organizations. However, organizations such as the U.S. Bureau of Census, as well as other geodata centers make their products available for free over the Internet or by compact disc.

“GIS data are useful in identifying property information. Local land use and zoning ordinances require that changes to property be recorded with the register of deeds” (O’Sullivan, Rassel, & Taliaferro, 2011).

One of the choices that one has when using GIS is to decide what area one can examine. “Data displays for a large area blur specific details while too much specificity may cause you to miss important characteristics” (O’Sullivan, Rassel, & Taliaferro, 2011). An example would be looking at data that is confined to one small area, one may not see similar activity in a neighboring area. Social conditions might not stop at an artificial boundary such as a neighborhood, city, or county limit.

Management, Ethical, & Issues Associated with GIS

Desktop GIS have the capability to design maps easily to show relationships; however, one should understand the shortcomings of maps. All maps represent their author’s point of view.

“Maps are imperfect because they are two-dimensional representations of the three-dimensional spherical earth (O’Sullivan, Rassel, & Taliaferro, 2011).

The transition from earth to map is called a projection, in which mapping utilizes many projections, all of which seek in some way to create a balance between preserving shape and distance.

Generalization is another issue with GIS as well. “Generalizing map data means to smooth or leave out certain levels of detail: too much detail and the map may be difficult to read and therefore not useful” (O’Sullivan, Rassel, & Taliaferro, 2011). Although, if one were to include little detail, important characteristics may be deleted. Generalizing is a choice that the individual need to make based on what they think is important.

GIS Mapping FunctionsHaving the ability to create and use maps is the backbone of a GIS. Program managers have a huge platform of possibilities relating to GIS implementation at their fingertips. When discussing GIS in the context of research, managers can use data about spatial attributes as independent variables to look at relationships to program outcomes as dependent variables.

Maps of earthquake shaking hazards are used to create and update building codes in the U.S.

Source: http://www.esri.com/what-is-gis/overview#overview_panel

Pin Mapping“Pin mapping is the electronic version of sticking pins into a map and looking for visual patterns in relation to their geographic locations” (O’Sullivan, Rassel, & Taliaferro, 2011).

An example of what a pin map was designed after is shown on the right. This particular pin map illustrates where the heaviest crime rates are in the US. This pin map is closely related to Hot Spot Mapping, which will be discussed in the next slide.

Source: http://irevolution.net/2009/03/16/crime-mapping-analytics/

A digital GIS pin mapSource: http://www.caliper.com/maptitude/gis_software/default.htm

Hot Spot Mapping“Hot spots are incidents or points of activity that have been smoothed to create density areas. The points could represent crimes, incidents of disease, fatal automobile accidents, or any other activity that has a specific address” (O’Sullivan, Rassel, & Taliaferro, 2011).

Crime hot spots generated from vandalism data for Lincoln, Nebraska, that have not been normalized. Hot spots are shown in bright red and located in downtown Lincoln, an area with a large population. Cold spots, or areas of low crime, are shown in dark blue and are located in suburban areas.Source: http://www.esri.com/news/arcuser/0405/ss_crimestats1of2.html

Analysis of the spatial dispersion of crimes by police beat in Redlands, California, shows that crimes in the western portion of the city follow major transportation networks in the area.

Source: http://www.esri.com/news/arcuser/0405/ss_crimestats2of2.html

Density Mapping“Density mapping is used for mapping activity that is continuous in a geographic area” (O’Sullivan, Rassel, & Taliaferro, 2011).

Performing density analysis with ArcGIS Spatial Analyst.

Source: http://www.esri.com/software/arcgis/extensions/spatialanalyst/key-features/density

The density function distributes a measured quantity of an input point layer throughout a landscape to produce a continuous surface.

Available density mapping tools include Kernel Density Line Density Point Density

Using GIS Functions: Examples of applicationsGIS functions permit program managers to design maps to study important social

and economic characteristics of their service areas, as well as put together the maps in different ways. “Managers can use GIS information along with knowledge of program goals and objectives to plan, manage, and evaluate programs” (O’Sullivan, Rassel, & Taliaferro, 2011).

Map and model potential hazards, determine their potential impacts, visualize critical vulnerabilities, and plan for special events.

Source: http://solutions.arcgis.com/emergency-management/

Planning for Emergencies

GIS & Computer Aided Design (CAD)

© N.TANCREDIPHOTOGRAPHY, 2013

With specialized tools, you can incorporate CAD data into ArcGIS for your analysis and continue to access and deliver your data in a CAD format.

With ArcGIS for AutoCAD, you can view live GIS maps and display symbology of all underlying GIS data structures in CAD. Include GIS basemaps and analysis results in your CAD designs.

Define the coordinate system within AutoCAD to automatically project maps on the fly without transforming CAD drawings or converting GIS data.

Source: http://www.esri.com/industries/civil_engineering/business/cad_integration

Arc News: Building Smart from the Ground Uphttp://www.esri.com/news/arcnews/fall11articles/building-smart-from-the-ground-up.html

Links and SourcesThe following are sources and links that explain more about the benefits of GIS technology:

O'Sullivan, E., Rassel, G. R., & Taliaferro, J. D. (2011). Practical Research Methods for Nonprofit and Public Administrators. Glenview, Illinois, USA: Pearson Education, Inc.

http://www.esri.com/library/brochures/pdfs/crime-analysis.pdf A PDF from ESRI that explains in greater detail the benefits of using GIS in law enforcement.

http://www.esri.com/industries/public-safety/emergency-disaster-management Links to PDF files from ESRI that explains in greater detail the benefits of using GIS in emergency management.

http://www.esri.com/industries/public-safety/emergency-disaster-management/brochure-flyer-whitepaper The following are links to white papers from ESRI which cover a range of emergency management topics.

http://www.esri.com/industries/public-safety/emergency-disaster-management/demos Videos relating to GIS use for public safety and emergency management.

http://www.connectedworldmag.com/latestNews.aspx?id=NEWS130501061151003&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Esri-News+%28ESRI.com+-+News%29 Social media meets emergency management