Topic 8

Geographic Information is information concerning places on the Earth’s surface, and the knowledge about where something is and – in reverse - about what is at a given location.

Geographic Information can be very detailed (i.e., information about the location of all buildings in a city; information about individual trees in a forest) or very coarse (climate of a large region; population density of an entire country).

In to-date world, also geographical elements can be organized and managed digitally, that means data are geographic, therefore holding a position on (or above or under) the Earth.

Geospatial technologies were developed to acquire, manage, display, represent, analyse geographical data – and also for making maps, these including dynamic ones.

In particular three main geospatial technologies are used for managing Geographic Information:

GNSS (Global Navigation Satellite System). GPS (Global Positioning System) is one of the examples. GNSS use satellites to determine the position of a receiver on (or above) the Earth.  Such position can be expressed as geographical coordinates and represented as a point on a (also digital) map.

Remote Sensing. It deals with acquiring (digital) data from a remote location, or data taken without being in direct contact. Also a picture of you taken by your classmate deals with soma date taken without being in direct contact you. In Remote Sensing, sensors (cameras, using visible light, ultraviolet, radar signals, laser, etc.) are mounted on vehicles like satellites, airplanes, helicopters, UAV, etc. to acquire data of the Earth’s surface (or of features above the Earth’s surface as the atmosphere). These data are in the form of satellite images, where each pixel holds a geographical coordinate and a value that can be mapped.

GIS (Geographical Information Systems) is an information system that allows: collecting, modelling, handling; retrieving; analyzing geographically referred (georeferenced) data.

Two views of a GIS: “A GIS is a set of tools to collect, store, retrieve, transform, display spatial data from the real world for particular purposes” (Burrough e McDonnell, 1998)

“A GIS is a database in which the most of data has a spatial index, and on which procedures can be executed to answer requests and queries on spatial entities in the database.” (Smith et al., 1987)

 Geographical data can be raster (as those from Remote sensing: digital images) and vector (points, lines and polygons: the restaurants, the streets and lakes/municipalities in your google maps / blackberry maps / bing maps / apple maps, etc.). Data can be organized in layers (as transparencies with different objects drawn on them and put one on top of each other on an overhead projector).

The evolution of geospatial technologies

Geospatial technologies has evolved and are to-date available on standard pc and laptops in the form of traditional GIS software packages or available in other forms: Virtual Globes (like Google Earth), Web mapping applications (like the recent Google Maps Engine) or apps for smartphones and tablets (like Viewranger or other geocaching / training applications as Runtastic, Endomondo,  etc.).

Geospatial technologies evolved also thanks to the widespread use of mobile devices and the Internet. So also ‘geography goes social’ as people produce and share data and information with a geographic component! Facebook, Twitter, Foursquare , Google use social (geographical) data to target advertising and for users’ profiling. The geospatial market seems having overcome the videogames market and covering 1/3 of airline industry value.

In the Web 2.0 logic (A Web 2.0 site may allow users to interact and collaborate with each other in a social mediadialogue as creators of user-generated content in a virtual community, in contrast to websites where people are limited to the passive viewing of content. Examples of Web 2.0 include social networking sites, blogs, wikis, folksonomies, video sharing sites, hosted services, web applications, and mashups. From Wikipedia: http://en.wikipedia.org/wiki/Web_2.0) Users can also produce their geographical data thanks to GPS-fitted portable devices and manage them in GIS packages or also on Web mapping applications (on-line GIS) or virtual globes.