As we prepare to launch a parish-wide geographic information systems department, it's important to think about data standards. How good is good enough?
This is a question all entities using GIS struggle with.
One of the purposes of a GIS is to gather information that will be used to make decisions. It's important to keep this in mind. The principle of "garbage-in, garbage-out" holds true for geographic data the same as for any other variety of database.
Every department will likely have different standards of accuracy that will be adequate for their decision-making processes. Some departments will choose to follow national standards for their areas of expertise.
For instance, the National Emergency Number Association (NENA) has published standards as a guide for designers and manufacturers of emergency call processing systems. These standards were issued in 2007, and will likely be updated in the near future. These standards are very specific to the needs of emergency response.
The problem is, very detailed data is very expensive to create. Therefore, there is a trade-off between the costs and benefits of acquiring the most expensive data. Cost-sharing in an enterprise GIS might be one way of accomplishing the goal of detailed data which can be used in multiple departments.
Since this post, I have met with Jack Gardner, GIS Manager for Terrebonne Parish. In Terrebonne, they use street data created by a contractor who digitized the streets from high-resolution aerial photography. Since theirs is a consolidated governmental entity, they were able to implement a workflow that ensures new streets have the same accuracy as the original data.
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