FAQ: Why isn't my area of interest included in the ivp?

2007-02-06T07:28:00.000-08:00

When we first started developing the processing software for the ivp, we had to make some decisions about the geographical extent we would process. As this dataset was conceived of as pertaining to those interested in forests, we used a variety of forest maps (e.g. the MODIS landcover and continuous fields products) to create a 1000m resolution mask of forested areas. We then tallied, on a 1 x 1 degree grid, the percent of 1000m pixels that were considered forest. When more than 10% of the 1 x 1 degree grid cell was forest, we flagged that cell as one that we would process. These 1-degree cells were then used to create a 5 x 5 degree grid (the basic unit of data distribution), where the presence of a single forested 1-degree cell was considered enough to flag that 5-degree cell as forest. These were then aggregated to cells that were approximately 20 x 20 degrees, which were used for our data requests to NASA. This largest scale of aggregation remains as a secondary scale for data distribution.

We recognize that, while these rules selected the vast majority of global forests, there are some forested areas that have not been processed. For instance in eastern China, there exist patches of forest which were not large enough to pass the "10% of 1-degree cell" criteria and were therefore excluded. We expect that other areas were missed as well.

The bottom line is that we only need to know what areas you need to have included in the dataset and we should be able to add then relatively quickly. Updates to the database will be shortest for those 5-degree grid cells that fall within the 20-degree subsets. Otherwise, we will need to make a new data request from NASA and that will take additional time.

Please post requests for adding additional areas to the ivp dataset as responses to this thread.

Welcome to ivpdiscuss

2007-02-06T06:48:00.000-08:00

This blog is dedicated to discussion of the use of the icesat vegetation product (referred to herein as the "ivp"), produced by Colorado State University's Center for Ecological Applications of Lidar, directed by Michael Lefsky.

In the interest of advancing the use of this data as quickly as possible, I have decided to use this blog to openly discuss problems, suggestions, FAQs and advances in using the icesat vegetation product. I urge everyone to be as open with their research as you feel comfortable with.

The main topics of discussion will be posted in the next few weeks, as the first iteration of the data and associated utilities are released.