GIS, Geographic Information System, allows you to associate information to a map. In which fields can it be used and what kind of technology is behind it
When we use an app or visit a website with information shown on a map, for example our navigation system, or simply search for a restaurant in a certain area, we are using a simple technology based on a century old idea: GIS.
GIS stands for Geographic Information System.
A system or GIS, can locate objects in space, therefore on a map, that are stored in a database and gathered on the basis of similar characteristics, managing them as geo-referenced thematic informative layers.
These are IT / geographic systems mainly designed for:
- territory management
- urban and infrastructural planning
- the study of the territory transformation over time
- the implementation of Civil Protection plans
- the creation of thematic maps (hydrographic, seismic, demographic, traffic, etc.)
- statistics, demographics
- the study of the archaeological-cultural / environmental / construction heritage
- GPS applications
These systems thus allow an accurate planning of the territory and the interventions to be carried out on it, house by house, street after street, in an extremely detailed and complex way.
GIS, its historical background
To fully understand what GIS is, let’s put what we know today aside for one moment. Its origin goes back to 1854, when in London’s Soho district a deadly epidemic struck the population.
A doctor named John Snow, began a study where he identified and localized contagious cases on a map of London, connecting the geographic distribution with the number of people infected.
Monitoring the course of the outbreak throughout time, Dr. Snow understood that certain areas represented the source of the disease.: that’s when the idea of geo-referencing a determined characteristic was born, therefore coming to a conclusion on how to operate. This is one of the first real applications of GIS.
By definition, GIS is a system that puts geographic information in relation with other information contained in a database system (demographic, environmental, urbanistic, etc..).
One of the first definitions of GIS in the digital era was introduced in 1986 by Peter A. Burrough, professor at Oxford University (UK):
“GIS consists in a series of software instruments made to acquire, store, extract, elaborate and visualize spatial data in the real world”
The elements that characterize GIS
GIS is integrated in software that connects typical database operations to geographically oriented analysis, connecting alphanumerical information to spatial information, obtaining precise georeferenced data.
Geographic information (maps, photos, etc..) play an important role in the decisional process, being easily and immediately comprehensible, even to non-technical people.
A GIS system is composed of the following elements:
- Software tools (GIS software, network, database)
- Hardware devices (computer, printers, plotter, GPS)
- Data (information, images, etc.)
- Methods (spatial analysis procedures, etc.)
- Human resources (analysts, users)
These systems allow the interaction of different IT-based systems:
- DBMS – database management system
- Image processing – raster images processing system
- Statistical software –statistical analysis systems
Data and procedures for their acquisition
Data are the fundamental component of a territorial informative system. They are distinguished in:
- Digital geographic data (vectors, raster, tables, database) can be integrated with other kind of informative resources (mixed-data system)
- Analogic data, usable through digitalization like: historical cartography on paper, photographs, etc
There are two types of data:
- Spatial data (geometrical, topological)
- Non-spatial data (thematic, attributes)
These data, can be shown as map diagrams (cartographs) or simple tables and can refer to a portion of a given territory and based on different applications.
On these cartographs, every symbol, every line, every color or layer has a meaning and all the gathered data is stored in a database.
Because of these peculiarities, GIS is different from other IT systems, proving to cover countless possibilities for its use in correlation to geographic components.
The applicative procedure and the work methods of a GIS system is developed in the following phases:
- Data acquisition
- Return of information
- Data update
- Data processing
- Creation of simulation models
- Representation model elaboration
There are different levels of GIS complexity:
- Level 1, consisting of a database that works on a single layer with simple data analysis and querying
- Level 2, organized on more layers with more complex analytic data querying
- Level 3, working on a more sophisticated data modeling technique, mainly as a decisional support system
Click on the link below to watch a short video on how GIS works.