Awareness of the Geography
of Northern Ireland is important not only for visitors but for residents alike. The Ordnance Survey
of Northern Ireland regards itself not only as a service but as an educational resource in promoting
an understanding of our spatial environment. It is our intention to supplement this section in the near
future with extra resources of benefit to students, teachers and indeed the general public. In the meantime
please find a brief introduction to maps in the form of definitions.
Maps
– an overview
A map is a visual representation of a given location
or
geographic area. It may be shown in many different ways, from a traditional paper maps to computerised
digital maps. A map can be practical, directing travelers from one point to another, or explaining the
world by attaching specific types of information to geography.
Direction
and scale are important elements of a map. A north arrow tends to indicate orientation. Distance
on
a map can be determined by the scale, which is shown by one or more ruled lines that mark off miles
or other lengths of measure.
Grid of latitude -
Most maps have a grid of latitude, which
measures distance in degrees north and south of the equator, and longitude, which measures distance
in degrees east and west of a prime meridian.
Map Elements
- Most maps
share a number of basic features. They assume a certain projection and scale, present location in terms
of coordinates, and have a legend.
Projection – We
need to remember that
maps are flat even though the earth is curved. As a result maps are distortions of how the Earth really
looks. For small areas, distortion is insignificant because small areas look flat. For large areas,
however, the distortion can be significant. The way a representation of the globe is depicted on a flat
surface is called the map's projection
Scale -
The size of a map
in relation to the physical area it represents is its scale, which is usually stated as a ratio or a
fraction. The larger the denominator and the smaller the fraction, the more of the Earth is represented
on a single map. Therefore, large-scale maps show a relatively small area and small-scale maps show
a large area.
Legend - Maps use sets of symbols to
indicate real objects.
For example icons can represent buildings and colours can represent elevation. The legend is a block
of text or a window in which the symbols used on the map are explained in more detail.
As
this section of the site is in its infancy with regard to development, any recommendations would be
welcomed (use 'feedback' link at the top of the page)
and we will do our utmost to respond to these communications.
