8 Misbeliefs About Making Map Data

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All of you who are GIS professionals know this isn’t true, but there are some people think that simply marking up a Google map is an appropriate way to create accurate boundary data. Even within the mapping industry, a few commercial providers of map data eschew the "GIS culture" and say that traditional mapping techniques actually hinder the production of data. We believe they are wrong, and here is why:

Misbelief #1: I Can Just Draw on Top of Google Maps, Right?

Unfortunately for those who are comfortable with this method, this is likely illegal. Not because Google would come after you, but because Navteq or Tele Atlas (their major data suppliers) would. If you use their streets to create a product, that's a derivative product and you owe them licensing fees.

Misbelief #2: Nobody Cares About Topological Correctness

Topological correctness simply means that the map data passes a series of fundamental GIS quality tests for usability. The problem with a lot of public map data is that there are fundamental errors: self-intersects, overlaps, slivers, small gaps, etc. Even if high-end GIS systems are used to create data, there's a high potential for such errors. If GIS practices aren’t in place, then you can be sure these problems will be compounded.

Misbelief #3: Map Data Should Be Free

Like many other areas in life, you get what you pay for with map data. There are free map data resources out there, but most of them are not thoroughly vetted before release. The primary exception to this is data created by paid government employees. Although, often the government is looking for different things from their data than a commercial user.

Misbelief #4: Anyone Can Create Map Data

neighborhood map

Because they are not experienced in GIS data creation, many amateur data compilers do not even recognize the pitfalls associated with their operating methodologies. GIS professionals are trained to create high quality data, and have the tools and processes at their fingertips to ensure a quality product.

Misbelief #5: GIS Thinking Just Restricts Your Creativity

I'm not sure why you would want your data company to be "creative" - maybe "innovative", but really you just want the results to be of value. And high-value map data requires highly engineered data creation processes. The most "creative" thing you want, as a user of map data, is a company that finds innovative ways to get you what you need, not to come up with new paradigms that are hard if not impossible to integrate.

Misbelief #6: Make it Once and You're Done

Data changes over time. Sure, county boundaries are pretty stable, but ZIP Code boundaries shift all the time. And carrier route boundaries are spastically changing. Even city boundaries and neighborhood boundaries evolve faster than you might think. So, if you do make data, you need to be committed to keeping it current and accurate.

Misbelief #7: Offshoring is the Way to Get Great Map Data

In our time-starved country, outsourcing to a foreign country with a lower cost structure seems very attractive. And I'm not saying that pure data businesses shouldn't consider some element of offshoring. But how can a foreign team accurately describe something as fuzzy and local as neighborhood boundaries in the US? And for more complicated datasets, the amount of time you'd spend managing and QCing your offshore team's work would be tremendous - far more expensive than licensing great data from the start.

Misbelief #8: You Don't Need to Be a Mapping Company to Make Good Data

Ok, this is actually true. If you have enough money and talent, you could build your own data. But even though Google, Microsoft, Mapquest, Nokia, TomTom, etc. could do it, they don't. Many of them have attempted it, and then realized the time and expertise involved. The latter two are buying companies that do nothing other than map data. Other company’s, like Zillow, have tried in their spare time, but realized the undertaking was too great. They’ve either aborted the mission, or, in Zillow’s case, released the data to the world and asked the public to fix it.

What do you think?