This Annual NLCD Reference Data Product includes the collection of an independent dataset of 8,360 30-meter by 30-meter samples across the Conterminous United States (CONUS). The Annual NLCD Collection 1 sample design was developed as a two-phase collection by a team of image interpreters as follows: an initial base sample containing 5,000 sample plots chosen purely by simple random selection, following by another collection of 3,360 sample plots (some of which were selected similarly, while others were targeted at particular map-defined strata) upon completion of the map. This approach results in a final stratified reference sample of size 8,360. The Annual NLCD CONUS Reference Data Product collected variables related to primary and alternate land cover and land use, change processes, and other ancillary variables annually across CONUS from 1984–2023. This product contains Annual National Land Cover Dataset (NLCD) CONUS Reference plot location data, annual land cover, land use, and change process variables for each reference data plot, information on the 'strata' and phase of collection each plot is associated with, and the strata map and overall strata counts for calculating inclusion probabilities of the stratified samples. The Annual NLCD Reference Data Product was utilized for evaluation and validation of the Annual NLCD CONUS Collection 1.0 land cover and land cover change products.
