Learn about the evolution of GIS, the types of map features you'll find in our data, and how you can display your information on screen.
The evolution of GIS
The story of GIS begins in the world of maps. A map is a simplified visual representation of real things from the real world. Maps can model the world in more than one way:A topographic map shows physical surface features; for example, roads, rivers and buildings. A contour map shows lines which connect points where a certain property has the same value; for example height above sea level and isobars showing air pressure. A chorochromatic map shows areas sharing a common feature; for example, political maps and agricultural crop types.
GIS applications combine two types of software. Graphics and computer-aided-design (CAD) technology influences how map geometry works. Database technology informs the management of attribute information.
A GIS professional understands both software disciplines, as well as geographic principles.
Data sources - map data
The human eye can interpret a large amount of information from a map. GIS records it in electronic form.
On any map, shapes and symbols illustrate real-world features, or what we call them. There are four categories of map feature:
Point (for example, a cross symbol represents a church).
Line (for example, a yellow line for a road).
Polygon shape (for example, a blue shape for a lake).
Text (for example, the name of a building, town or range of hills).
The most common form of GIS data reflects topography – the physical structure of the land surface. Topography includes the relief of an area (the shape of its surface) and the position of features, both natural and man-made.
As well as topographical data, other sources of information can link to a GIS.
Hedges highlighted on OS MasterMap Imagery Layer
The image above shows how a layer of environmental information can be overlaid on a map backdrop.
Even aerial and satellite imagery can be loaded into a GIS and viewed along with other data for the same area. The most powerful GIS applications use data from a range of sources.
Ordnance Survey data and GIS
We offer many different GIS products, from road atlas mapping images to street-level data. Our most advanced products need to be stored in a database. They let you look up information about every point and line on your map.
Not all data in a GIS looks like a map. For example, AddressBase products by themselves on screen are a sea of dots, so you need to display a map beneath them.
The power of our address products lies in how they match postcodes in your data. In AddressBase, we tie each postcode to a National Grid reference. When you create a link between a database containing addresses and your GIS, you can display your addresses as pins on a map. This lets you spot hidden patterns or plot the shortest route between them.