Basics Theory of Global Positioning Systems Technology (GPS)

Back to the basic – by popular demand

Mapping is any activity carried out with the intent of collecting credible and accurate data on an object e.g. Building, roads, human genome or phenomenon e.g. buying patterns, smuggling and illegal immigration. To go a step further, spatial mapping is when the geographical coordinates of the object or phenomenon is also taken. In other words, the GPS coordinates!!!!

So what are geographic coordinates ooh!!

Geographic coordinates are the X and Y of any object position on the face of the earth pronto!! X stands for the longitude, Y for the Latitude. The X and Y tells us the unique position of an object on the face of the earth.

How do we now get the X and Y coordinates when mapping? Namely on the field and in the laboratory or on the Workstation even your mobile device!!First Choice? Lets take field mapping first

We deploy a technology called Global Positioning System Technology, GPS for short. The technology works through what we know as GPS Enabled devices. These are common now as almost all telecommunication devices, cars, trains even wristwatches are now GPS Enabled!!!

How do we use these devices?

When we use these devices to map a road for example, we use certain functions that exist in the devices. These functions assist us to get a real life representation of how the road looks. Really, a road doesn’t look like a lamp post, neither does it look like a building!!!

Note: not all GPS Enabled devices have Mapping capability but all have the ability to register the basic X and Y of a location. Devices designed with the objective of mapping are usually labelled as so. For example- Handheld GPS devices, Rugged GPS Enabled Notebooks amongst others.

So what does the GPS technology map? The GPS Enabled devices map what we call features. Features are of three main kinds- Points, Area and Lines.

Second Choice: How do we now get the X and Y coordinates when mapping? When one cannot go out? Mapping can also be an indoor activity lol One cannot map human genome in the garden anyway!!! Lol

Today, we are all familiar with dynamic or internet based maps, satellite imagery and aerial photographs. In a GIS Laboratory or Workstation and with the right tools for analysis and interpretation, certain X and Y coordinates of recognizable locations on the earth surface can be extracted. Note that these remotely sensed datasets must be themselves georeferenced.

Even simpler is your handy google maps engine. Here by simply clicking geocoded locations on the face of the earth, their X and Y coordinates can be extracted For example putting in a search for lagos will generate a marker on the google map engine that contains the X and Y coordinates of Lagos!!!!!!

Go to presentation page on menu bar and click links on presentations titled 'GPS Data' and 'Coordinates&Projections'for greater details