how can I get from… to…?

Some doubts related to the meaning of diagrams reference elements and their geographical range variable seemed to emerge from the workshops (Barcelona–London). In order to clarify these concepts I will explain their differences and importance with an example of a recent personal experience:

I have just returned from a four-day break in south Spain. As it was my first time in Murcia, I found myself a bit lost and hard to find the correct route to get to the main square, Plaza Circular, from the bus station. So, I decided to ask a policeman from the station how to get there. He explained me the route and gave me some guidelines and references, however, after walked a couple of blocks I preferred to ensure whether I was in the correct direction or not. This time, I asked another random person from the street. As the previous one, she kindly explained me how to arrive to the main square using more or less the same particular words and expressions than the previous man, instead, for example, to common words like street names or a quantity of blocks. Both of them were referring to local directions and coordinates: a hairdresser’s name, a telephone store name, a square, another shop, traffic lights, sidewalks…
Fortunately, this woman noticed that, even though we were both speaking the same language, I wasn’t completely sure about her explanation. So, she took an A4 paper and a pen and drew a quick map of the zone, including all the local references that she considered key and useful to get my destination.

Explanation drew by a local person to go from the bus station to the main square, showing key referential elements: hairdresser, shops, traffic lights, gardens. (Murcia, Spain)

Although, I arrived to the main square, some days after that, I stopped in the tourist office to ask for a tourist map. When I looked for the bus-station-main-square route, I wasn’t surprise at all to find completely different references in that map: street names, blocks, parkings. That is to say, international references.

Map given by the Tourist office. (Murcia, Spain)

Tourists maps are created for tourists and they have to be understood for the more quantity of tourists as possible. They have to employ an international and conventional language, although, they would be harder to read for local people.

Local is defined as something that is understood by a restricted audience from a particular place, country, city… As an example, this means that foreign people would barely understand the references given by both the woman and policeman or would think that this information was meaningless.

Reference elements depict those key devices that enable readers/users to navigate into a diagram. References elements do not have to be always geographic elements. In this case, they are urban-rural references.
Geographical range variable refers to the audience’s degrees of comprehension of those reference elements.