Since the data is still being reviewed and has not undergone a strict peer-review process, this information should only be used as a reference, and not absolute fact.
As with any land use change analysis, much of the results are completely dependent on how the land use categories were defined. Without understanding how each land use group was defined, and arrived at, the data risks serious misinterpretation.
Thus, please read through the provided background and methodology (or contact us!) before using and/or interpreting any of the summary numbers provided in this section or the available data..
A few key points to consider and remember:
1. The smallest area mapped in this project was 10 acres
2. Classification consistency was tested, and received a high level of accuracy; however, classification accuracy was only tested on a minimal number of points and a relatively small area.
3. Please use at your own discretion.
4. If you are going to download the data, please read through the metadata.
5. The data includes a buffer into federal lands and water; for any queries or summary statistics, you will need to exclude all areas outside of the study area.
Please contact us with any questions, suggestions, and/or comments. We would like to continue to ensure that this data is as accurate as possible. If you discover any errors, please be in touch.
Example of using data
Let's say that we wanted to know the sum of all areas (in thousands of acres) that were classified in one of the three forest-related land uses in 1988 and what general land uses (forest, agriculture/mixed rural, developed) those areas were classified in 2004, by county.
Using the table provided in the data section below [Table], we could write and run the following query in SQL:
SELECT [Table].County, [Table].LU_1988_GROUP, [Table].LU_2004_GROUP, Round(Sum([Table].[Acres])/1000) AS [Acres (000s)]
Or, if we preferred to use the graphical user interface in Microsoft Access, we could design a query to look like the one below (click on the graphic to display a larger version of the query in a new window).
Once we ran the query, we would produce the following table:
And, we could total the areas that remained in forest land use and the areas that changed to other land uses. As the table below shows, using the land use data from this project, we estimate that approximately 8,483,000 acres of non-federal land in western Washington were in forest land use in 1988; in 2004, 7,070,000 acres remained in forest land, while 796,000 acres changed to agricultural/mixed rural land uses, and 401,000 changed to more developed land uses. The remaining area (62,000 + 154,000) were classified as changing to water or other unclassified uses (clouds, haze, etc.).
And, we might even be able to make a simple pie-chart.
Four datasets were produced for this project: one land use dataset for each of the 1988, 1996 and 2004 study periods, and a land use change dataset that quantifies the change over the same period. We are also providing a text file to facilitate data summaries that is the combined data from all three datasets for those that do not have access to a GIS. More information, as well as direct links to download the data, is provided in the table below.