Reverse geocoding. Easily done! Right?


My input information comes primarily in the form of latitude/longitude coordinates. I need to assign a street address to each of my lat./lon. combinations. What do I need to know?


Reverse geocoding is a difficult task. The reason is that a parcel of land (upon which a house may lie) may be anywhere from an acre or more in size to a tenth of an acre and the house may be located anywhere on that parcel. The geocoordinates can also be anywhere within that parcel (at best) or approximately near it. With that in mind it should be understood that a single point (a set of geo coordinates) will, at best, only approximate an address.

I would compare it to translating from one language to another. The most efficient method is an exact word for word translation. But that doesn't work idioms or colloquial expressions. Let's start with this common phrase, "cool your jets", meaning to relax, don't worry.

Use Google Translate to convert that into spanish and you get "enfriar sus reactores", which quite literally means to chill your engines but has no meaning other than the literal wording. It sounds like a manufacturing process to me. Now, if we Google Translate that exact spanish phrase "enfriar sus reactores" back into english (remember this is the same process but in reverse so it should give the same thing we started with) we get "cool its reactors". That doesn't mean a thing to me.

This is not to say that reverse geocoding is impossible or that your results will be useless. Far from it! This illustration simply shows that you must consider the accuracy of your input as well as variances introduced in translation.

If I were jumping off a platform five stories up, into a bucket of water, reverse geocoding may not be the best approach for my planning.