By Marcus Boit
A map is a graphic representation of a portion of the earth’s surface drawn to scale. It uses colours, symbols and labels to represent features on the ground. The ideal representation is realised if every feature of the area being mapped is shown in its true shape.
A map provides information on the existence, the location and the distance between ground features, such as buildings and natural features like water bodies. It also indicates variations in terrain, heights of the features and the extent of vegetation cover.
Therefore, to ensure structures are properly located, a map must be drawn and those involved in the planning and allocation of spaces must be skilled to read the maps and apply them accurately.
A Global Positioning System (GPS), on the other hand, is a gadget that can be used to navigate properties in an area of interest. A simple one is the hand-held GPS while a complex one could be Doppler GPS. The later is more accurate and is based on satellite ranging. Anyone can acquire the hand-held GPS for their personal uses such as locating a place or a building.
Satellite imagery
Topographic maps entail more complex features and have more details. With the scale, one can measure the size of properties on the map since it directly relates to what exists on the ground. It may be categorised as obsolete because it is not real time and things change with time.
And although a recent aerial photograph can show changes that have taken place since the map was made, ground features are difficult to identify or interpret in a photograph.
However, the advent of satellite imagery on the Internet has brought in more knowledge and usability of data in locating and measuring properties.
Although many people are not aware of their existence and use, Google maps, open street maps and Yahoo maps are readily available on the Internet.
Google maps
I recently used Google maps to locate land whose boundaries I was to verify. My client had given me the roads leading to the plot and using Google maps, I clicked on the starting point (where I was at that moment) and where I wanted to go (the location of the property). The directions were clear and precise.
These Internet maps have the capability of overlaying with the recently acquired satellite images and one can visualise the characteristics of features such as the size and shape of a particular land or plot. One can also see the shapes and heights of buildings and road lengths.
Google maps can also be used to locate tourist destinations, hotels and places to check in for coffee or tea and recreation areas among other places.
One of the major advantages of satellite images over simple photographs is that one can zoom in and view details of places.
So, next time you are stuck and can’t find your way to a certain location in a city or town, especially abroad, just Google!
However, not all data of places in Kenya and other developing countries is available on the Internet and when it is there, the details are often scanty.
The satellite images in some of the developed countries are so real time and advanced that one can view moving objects such as trains on the Interned.
With the embracing of modern technology in Kenya and the upcoming development of techno and mega cities, Kenya needs to adopt the use of satellite image technology. It will not only help in the quick location of places and buildings, but will also guide in planning the placing of important facilities.
The writer is a geographic information systems expert and lecturer at Jomo Kenyatta University of Agriculture and Technology.
