One of the oldest and most difficult problems that human beings have always had since their presence on earth is figuring out their exact position.
Written by Maurizio Foderà
At a first glance it may seem like a simple problem to solve, in fact, if we imagine our position in respect to other fixed features on earth, we immediately can find a sense of comfort thinking we have no problem. But if, for example, we are in the middle of nowhere or surrounded by unknown objects, with some similarities but not easily recognizable as a reference point, how can we solve this problem? Do we look for direction as our ancestors did in the past, using the sun or the stars? Or do we use well know ground control points which have been used by surveyors such as myself for many years?
In either case the solution to the problem is not easily accessible to everyone and you really must be equipped with the proper skill set and tools to effectively deal with each situation.
Someone may say, “today we have GPS!” Correct! And it is a great invention but do we know what it is, and what’s behind it? Do we have a clear idea about latitude and longitude coordinates, what are those numbers that identify our position on the ground in a given “reference system”?
As first post in this blog, where the main reader is the Geomapper for Development, I would like, above all, to define a path to be shared with you all.
The path that I want to define will not be just a technical one, although we will walk through technical aspects. Mainly I want to share a vision with everyone. The vision will include topics that may be useful in our GeoMappers activities, which will be helpful to us during our worldly travels whereby our projects for development will come to fruition.
Will I succeed? I hope so but I would also like to have your participation on this endeavour. I encourage your feedback, which will not only be insightful but will also provide me with the motivation to look for additional topics focused primarily on our areas of interest and not just leisurely readings.
With this article, we will begin to clear up useful issues that may arise in future articles.
“Where is it? Where are we?” I believe that these are the questions we have to answer when we want to map any feature or location: a well, a house, a tree, a road, etc.
“Where is the well?” “Where am I in respect to the well?”
To answer these questions, we need a reference system, an X-Y or North-East system, that allows us to frame these present objects on the ground and that we want to represent on a map. Thus we need a coordinate system that allows us to define our position and the position of the object that we want to map related to an origin and to a system of axes.
Everything may sound simple and easy going, we only need to build a reference system and the problem is solved!
Everything would be simple except that there are so many reference and coordinate systems whereby one page would not be enough: An example of the available reference systems can be found on this page Spatial Reference.
Using the Well as an example, a single point being surveyed, may have different identifying coordinates, in relation to the reference system I’m assuming at that given time.
After obtaining the point coordinates, we have another question in addition to the first one: “What it is the reference system of these coordinates?”
We will answer this question in the next article as because we need to first face the issue of the earth being an irregular shape, which has over centuries produced different references and coordinate systems.
Photo credits: Dischro Creative News