The "data" sheet contains the county x variable matrix, while the "metadata" sheet contains the variable definitions and sources. For a complete description of sources and the content of variables you should consult the Data Dictionary on the EcoTrends-Socioeconomic Catalog (http://coweeta.ecology.uga.edu/trends/catalog_trends_base2.php) since the data collection procedure and sources used where the same. Nichole Rosamilia compiled all the data for the airshed as well as EcoTrends in case you have any particular questions that are not addressed in the data catalog or below. A few points to note on the attached data: 1) '-9999' indicates a null value - prior to a given county coming into existence there is no data so it is recorded as null; periodically, and typically for no recorded reason, no data will be recorded or available for a given county so again it is recorded as null. 2) the units of measure on certain variables, e.g., CWAGE (commercial establishments), changes over time from dollars, to thousands of dollars, to millions of dollars. Nichole left the data as it appears in the original rather than modify it on entry. For the on-line version we run the data through a script to standardize the units of measure, but that happens later in our data processing. The approximate airshed for the VCR/LTER was based on translation (of the oxidized nitrogen airshed for Shenandoah National Park created by R. Dennis of the Atmospheric Sciences Modeling Division of ARL, NOAA and NERL USEPA). The original Shenandoah National Park airshed was digitized from a printed copy, then the centroid of the airshed polygon was moved to from the park to the Virginia Coast Reserve. This was then intersected with ESRI counties data to generate the list of needed counties. A copy of the shapefile and a PDF is included in the "vcrairshed.zip" file in the data directory.