Saturday, December 30, 2006

Math for Maps - Experimental Chapter Of The Free GIS Book

I have started working on a chapter for the Free GIS Book that is being hosted at the OSGeo. I'm doing this in an effort to become more involved as a member of the organization, and I thought this would be a small way that I could help. The goal of the chapter is to explain some of the math mapping professionals encounter every day. I hope this chapter fills what I think is a void in current educational material for mapping professionals.
You can find the introduction to the chapter that I have prepared, and the table of contents here:

I encourage other GIS professionals to participate in the writing of the Free GIS Book. I also welcome any suggestions, constructive criticism, and corrections that you can point out to me as you read the material I've developed for the chapter. I hope to add new material every Sunday morning. (This is the only time its quiet at my house.) Tomorrow morning I hope to actually start on the first part of the chapter, which will be dealing with some of the math behind measurments.

The Sunburned Surveyor

Posted on 6:51 AM | Categories:

The Quarter Million Dollar Shapefile...In Florida?

I received a couple of comments on the post about the $250,000 parcels data in Santa Clara County, and I wanted to follow up with a post of my own. One of the commenter's who works with parcel data in Florida pointed out that there was a law suit and court decision, as well as an attorney general opinion, regarding this very same issue in his state. (You can read this commenter's blog at In both cases the data was made available to the public, and in the first case the court found that the government agency could not impose licensing restrictions of any type on "public records".

Here is a link to to the court decision and attorney general opinion:,%202004/2D03-3346.pdf!OpenDocument

I would like to express my agreement with something the commenter wrote: "Hopefully this case set a precedent for Florida. It just takes time and enough people to raise a concern over the issue for most government entities (county, city, towns, etc.) to change their attitude as far as GIS data being considered public records."

I wonder if the OSGeo would be willing and in a position to champion this cause across the United States and other parts of the world. Private companies that work with public GIS data often decide to suffer under the licensing restrictions and fees imposed by a government agency rather than risk angering a potential client by pushing the "free access to public records" issue. A neutral third party like the OSGeo would provide an appropriate champion for this issue. Public data plays a critical role in GIS in the United States, and as a community we want to make sure free and unencumbered access to that data continues.

I also received some information about a United States Federal policy of creating free or low cost access to geospatial data created and maintained by the United States Federal Government. I'd like to talk about that some more in a future post.

The Sunburned Surveyor
Posted on 6:38 AM | Categories: