What is a map?
A map is two-dimensional representation of geographical features and it
represents the reality around. However, even three-dimensional features, such
as topography, can be incorporated in a map using ad hoc symbols. Geographical features can be both physical objects,
such as buildings and streets, group of homogenous objects such as cities,
woods and imaginary objects, such a geographical borders.
What is the most important entity in a GIS?
The ability to form a connection between geometrical data (maps) and the
attribute data (a table). The programme does this using a “link”.
What is the difference between “spatial data”
and “none spatial data”?
Spatial data, such as buildings, roads…, can be defined with a specific
position (i.e. x, y and z coordinates). Non-spatial data on the other hand do
not have a defined position and no specific spatial delimitation and thus do
not have specific coordinates. Examples of non-spatial date are precipitation,
temperature, air pollution levels…
What kind of different geometrical objects are
there in a GIS?
There are three kinds of geometrical objects: point objects, lines and
Which are the four most important functions a
GIS must be able to handle?
programme must be able to handle data input, data storage, data structuring and
data output, as means of communication with the user and as basic action to
build up analysis and interpretation-.
Describe the concept of spatial information.
Spatial information means the connection of any kind of data with
geographical coordinates, as example the presence of trees in a given location,
temperature at a particular location and so on. Given this spatial information
does not need to be static, and can describe also phenomena occurring over
space and time, as example a car moving along a road, or pollution level varying
over time in certain area.
Describe some sort of an analysis which you can
do with a GIS.
An example of analysis that can be implemented with GIS is the research
of the connection between income, weight and proximity of grocery store selling
Or the distribution of soil pollutants in relation to the
presence/proximity/traffic volume of roads. With GIS it is possible to estimate
and model also future impaction of particular action: for example, we could
estimate the amount of forest loss upon road construction. Therefore GIS can be
a useful tool for decision makers and policy implementation.
Describe briefly how the “linking” in a GIS
To be able to connect different objects that belong to each other a link
has to be established. A link is a unique identifier, a specific alphanumeric combination,
assigned to objects belonging to the same group. A real life example could for
instance the assignment of social security numbers. Each of this number is
connect to a person and to several “objects” like medical records, bank
account, gym membership… and even if there would be two person with the same
name the use of a social security make impossible to mix them up. In GIS this means
that certain specific area (geometric data) are connected to information such
as population density, pollution levels, income… and this connection is made
possible by the fact that the same unique identifier is associated -linked-
with each one of this geometric data and their specific attributes.
Describe the cycle of the GIS handling.
of data (data are transferred in a database)
management (data from different sources can be combined, as for instance data
resulting from sampling and data obtained by other databases)
of results need to be communicated to the decision maker/final users as part of
the information needed to make decision
result in changes in the real world
these changes data needs to be collected…