Frequently Asked Questions
What is a Geographic Information System?
A Geographic Information System (GIS) uses computers and software to
map and analyze places and events on the earth's surface. GIS allows a
person to view, understand, question, interpret and visualize data in
ways that are not possible by simply reading a report or examining
figures found in the rows and columns of a spreadsheet.
Nearly all county government information has a geographic component to
it. Examples of this include a property's address, a manhole location,
a street, and a city's jurisdictional boundary. GIS consolidates and
integrates all this diverse information so it can be managed more
effectively and efficiently.
What can GIS do?
Interpret and Visualize Data – identify relationships, patterns, or trends
Model scenarios - test various hypotheses and see outcomes visually
Integrate Systems – bring together disparate data and technology
Facilitate and Improve Decision-Making – include geography
A GIS can be particularly effective as a decision-making tool in such areas as:
- Economic development analysis
- Management of the environment and natural resources
- Infrastructure management - transportation, water and sewer
- Property records management
- Comprehensive planning and zoning
- Public Safety - fire and police
A GIS can help answer spatial analysis questions:
Where is a particular feature? (facility, hydrant, parcel, street, etc.)
What features are
within x-number of feet or miles of this other feature?
How many linear miles of roads will be resurfaced?
What is the
shortest route between this location and another? What is the fastest route? Where is the
nearest police or fire unit that can respond?
How is Cobb County's GIS Organized?
The GIS is organized as a balanced, distributed system, with both
county departments and a central GIS core group working together to
ensure the effectiveness of GIS.
The majority of spatial database development, maintenance, analyses,
and mapping take place within the departments. The county departments
have the flexibility to organize their departmental GIS units to meet
their mission goals and fulfill their commitments to the countywide GIS.
What is a Digital Orthophoto?
Most digital orthophoto imagery is captured from aerial photography.
Scanned images are rectified to remove distortion so the images are at
a consistent map scale. Three types of distortion are removed.
Distortion caused by the camera angle and distortion caused by the
camera lens. A digital terrain model is used to remove distortion
caused by a landscape's terrain. A typical orthophoto project consists
of hundreds of photographs that have been rectified and mosaicked
together. Mosaicking involves balancing adjacent photographs'
radiometry, which refers to an image's color, brightness and contrast.
