Correct county areas with sidebars for Virginia

Historically, Forest Inventory and Analysis (FIA) has processed field inventory data at the county level and county estimates of land area were constrained to equal those reported by the Census Bureau. Currently, the Southern Research Station FIA unit processes field inventory data at the survey unit level (groups of counties with similar ecological characteristics). In short, the estimation unit has changed from an individual county to groups of counties. However, changing the estimation unit to a survey unit does not constrain the total area of each county when expansion factors are used. Here we provide a method to constrain published FIA estimates of total area at the county level to equal those of the Census Bureau. To accomplish this, we derive an expansion factor formula. Virginia serves as a case example of the techniques because of its unique geo-political boundaries.