Submitted by John McCombs on November 28, 2011
What is a Change Matrix? No, it’s not something from the movie involving Neo or computers using humans as their energy source. Although at first glance it can be just as confusing. A change matrix is a table, similar to a spreadsheet that quantifies the amount of change that occurs between two dates of land cover. It can be used to analyze the multitude of potential land cover change...
Submitted by Nate Herold on November 21, 2011
I wrote a few weeks ago about resolution and stressed the equally important (and often under appreciated) concept of Minimum Mapping Unit (MMU). And, that if you have a significantly large MMU, it almost doesn’t matter what the input resolution of the imagery was. I’m going to build on that previous discussion a bit and make a slightly finer distinction between level of spatial detail (represented by those two previously covered concepts) and mapping accuracy.
Submitted by John McCombs on November 14, 2011
What is the difference between land cover and land use?
Submitted by Kirk Waters on November 7, 2011
Every so often I get a question from someone that makes me realize I haven’t done a good enough job of describing what’s going on in the lidar distribution system of Digital Coast and why we do certain things that might appear crazy. The most recent one involved a data set that is about five years old and a user was trying to fill some gaps in their copies of the original data. When they downloaded the data from Digital Coast, they were showing just over half a foot vertical difference from the originals, though the points were horizontally right on.
Submitted by Nate Herold on October 28, 2011
As a producer of moderate resolution land cover data, I am often asked questions about the spatial resolution of our data. I have gotten used to the fact that 30 meter pixels of our C-CAP data are not always seen as ultra-sexy and the reaction that they “are not good enough.” And they aren’t in some instances, but then again, sometimes they are (and sometimes it doesn’t matter, as they are the only/best thing available). What I tell people, though, is that the resolution itself isn’t enough to determine whether these p
Submitted by Kirk Waters on October 24, 2011
Over the last year we’ve been working on mapping the possible inundation that sea level rise would bring to the coastal community. We quickly ran into a serious question. What amount of rise can we map given the accuracy of the elevation? This ought to be an easy question. Surely there are mapping standards we could follow. Alas, there are multiple mapping standards and what you pick depends on what you think you’re doing and the assumptions you make about that process. I’m going to look at a few options for looking at the problem and maybe a different way to think about mapping standards.
Submitted by Kirk Waters on October 17, 2011
The staff at Coastal Services Center get a lot of technical questions and provide a lot of answers, but those answers don’t generally get published even if they might be common issues. Sounds like material for a big page of frequently asked questions. However, a big FAQ doesn’t allow other people to add comments, clarifications, or new ideas. In addition, there are times when we’d like to put some ideas out there for the community to chew on without requiring or implying the corporate seal of approval.