martes, febrero 08, 2011

Cuando un Mapa nó es un Mapa ?



GIS News, Articles, Maps, Data, Tools

Sunday, February 6th 2011
When is a Map Not a Map?
By Adena Schutzberg

Summary: The term "map" has a very broad definition, especially for those who study geography. But, what one thing can you remove from a map to make it something other than a map? Executive Editor Adena Schutzberg found out one morning when her vision of a map was in complete opposition to one found on a friend's GPS-enabled running watch.

Topology of a GIS "Map".

Recently, while out running with a group, Victor described how he'd spent some time the previous day watching a YouTube video about his GPS watch.

He's had a Garmin Forerunner 405 for a few years now, and had finally gotten around to exploring the functionality that's supposed to help guide you back to your starting point. My older model of the Garmin also has this functionality and I, too, had never bothered to learn about it.

Our conversation went something like this:

Victor: It has a map.
Me: A map? Of just the U.S.?
Peter: No, an etch-a-sketch map.
Me: With streets on it?
Victor: Yes.
Me: How detailed?
Victor: Well, when you zoom in you just see lines.
Me: Are there street names?
Victor: No.
Me: Then it's not a map.
Victor: Yes, there's a map!

We ran another half-mile or so until I parsed the very accurate description of the maps created on the Forerunner. And, the key word was "etch-a-sketch." When another runner, Peter, referred to "etch-a-sketch," I didn't really think of the old red-bordered drawing tool with two knobs, but rather the most line-like, worst maps I could picture. I conjured up a map made of TIGER data, which of course has some smarts and covers the U.S. I was thinking of the basemap onto which a route would be drawn. Victor and Peter were thinking of the map that mattered to them, the map of the route, but without a basemap. That would indeed look like an "etch-a-sketch" map, a bunch of lines with no basemap, and thus, no context.

What I could not imagine, in 2011, of course, was that any electronic device would not have a basemap. The Garmin Forerunners, at least the ones we were using, do not have a basemap. The map is indeed, just an "etch-a-sketch" line with no basemap, no coordinate references and amazingly, no real-time, "you are here" symbol. When Victor noted it had streets on it, I finally understood that he meant it draws the streets that you run down.

Victor noted that the device provided an arrow that pointed to your starting point and provided a "crow flies" distance to it. He suggested you could use that information, along with the "etch-a-sketch" map, to navigate back to the start of the run. I really didn't like that idea at all. I far prefer to use landmarks to navigate my way back.

Now, while it's interesting that in 2011 the Garmin sports devices we carry do not include any sort of maps, it's far more interesting to me that my understanding of a map required a basemap and Victor's did not. I studied cartography and have a master's degree in geography. Victor studied astronomy and is always making fun of his lack of a sense of direction. Victor uses his iPhone's navigation quite a bit. "I'm using the blue dot to get to ..." he's been known to write on Facebook. I have yet to use Google Maps on my Android device.

When I began studying geography I really liked the broad definition of a map: "A map is a representation of a structure and a structure is a set of elements and the relationships between them." When I learned that in my "Human Habitat" course in college the professor drew a benzene ring (the 6 carbon atoms linked together in a circle) and asked me (knowing I was majoring in chemistry) if that was a map. I said it was. We were in agreement.

Spin forward nearly 30 years, and I have 20 years of experience using GIS. Now my understanding of a map is very different. Perhaps 98% of the maps I've seen or created in my career in geospatial technology were some version of "dots on a map," that is, data of interest (points, lines or polygons) overlaid on a basemap. Sure, some of those data came from analyses, but the end results were plunked down on a basemap. That's still, I'd argue, the killer geographic visualization product. If it were not, why would Google, Bing, Yahoo, MapQuest, OSM, Esri and others offer up such lovely basemaps onto which to plunk down our data?

Today, the dominant graphic most people have in their head when asked to picture a map is, I suspect, of data on top of one of these basemaps. I'm not sure if that's for the best or not, but I do appreciate that at least some people, Victor for one, have no qualms about a map not being placed on a basemap. That said, I fully expect Garmin to add basemaps of some kind to the Forerunner devices in the near future.


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