Geographic Information System
GIS is a system that includes computer software and hardware, spatial data or geographic information, people, and procedures to solve problems or provide solutions.
- The computer software and hardware are the tools used to create your product.
- The data is the materials from which you craft your product.
- The people are your workers, they require skills derived from experience and training.
- The procedures are the steps and processes used to create your product from your materials.
- Often customized applications, scripts or batch routines ease the use of the GIS to perform specific or repetitive operations to create your product.
Any GIS which lacks one of these components is a desk lacking one of its legs. Hardware and software are idle without both data and trained operators. Operators can not work or will produce questionable products without specific and tested procedures. The product of a GIS can be either a hardcopy paper map, or an online data query system, or the answer to a specific spatial question.
A GIS is generally capable of collecting, editing, storing, checking, integrating, manipulating, analyzing and displaying data related to positions on the Earth's surface. Typically, a Geographical Information System (sometimes referred to as an LIS or Land Information System) is used for handling maps of some type and the tabular data associated to the features in the map. These might be represented as several different layers where each layer holds data about a particular kind of feature. Each feature is linked to a position on the graphical image of a map, which is "geo-referenced" or geographically referenced.
GIS features fall into one of the following broad classes, which may be called by various names:
- Lines, Arcs, Segments
- Polygons, Areas, Regions
- Annotation, Text
What can a GIS do?
GIS uses fall into four classes:
- Basic: archive or file for accessing up-to-date and reliable information on the various elements in the system.
- Planning: accessing data for planning at all levels of detail, from conceptual planning to detailed design.
- Management: decision-making at all levels.
- Aggregation of information.
What type of problems can it solve:
- Locate site for a new store or public building.
- Track the movement of vehicles over time.
- Record and access property records.
- Plan bus, delivery, or rubbish pickup routes.
- Manage utility and industrial facilities.
- Study the range and growth of plant and wildlife communities.
These are only examples of the problems which can be studied or managed with GIS. Any task which involves location or spatial data can be handled within a GIS environment. This doesn't mean however that all spatial related questions are best solved inside a GIS. Efficiency of scale helps determine when a GIS approach is best applied. The investment in creating a GIS is useful in managing the data for municipalities or large landowners.
Data is another factor determining what type of problem you can study with a GIS. Where does it come from and what do you know about it? These two questions are linked with what level of questions your data can be expected to answer. The quality, source and scale of your data are all important to its application.
What differentiates a GIS from other computer based mapping systems? The primary difference is the data linkages that exist within a GIS. The user has the capability of linking almost unlimited amount of data to features within the GIS. The user is able to examine spatial features based on their data and visa versa.
A spatially intelligent GIS is also capable of locating features based on the location related to other features and their spatial distribution. These capabilities make GIS the leading method for cartographic composition.
CADD systems can create spatially correct maps but have fewer abilities to links data to the map information.
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