Development MV Temporal Change

The Nature Conservancy (TNC) completed a detailed vegetation mapping of Martha's Vineyard in circa 2000 (mostly based on aerial photos and field observations from various years in the 1990s). Their classification included a [Community] attribute containing a 'Developed' category. Per their attributes of [Attribute] and [Typedesc] one can see that this category included: Residential, Commercial, Industrial, and Institutional Development; along with Junkyards, Sand & Gravel Operations, and Paved Roads. The Martha's Vineyard Commission's (MVC) vegetation dataset (publ Oct. 2025 rev. 1/8/2025) was based on interpretation of aerial photos acquired in 2021 and local expert review/QC of the data. For this analysis, 'Developed' included the [Final Level] categories of Manicured Grasses (MG), Impervious (I), Roads Surfaced (RS), and Roads Unsurfaced (RU). In the [Level 1 Code] attribute T represents Terrestrial and D represents Developed. In the complete vegetation dataset, the Manicured Grasses are assigned to the broader category of Terrestrial. The attribute [Community Code] is included, but for this particular subset of categories, the [Community code] is identical to the [Final Level] value. The acreage of each polygon is provided in the attribute [Acres_dbl]. The [Change Summary] attribute provides a synopsis indicating the type of change that has occurred: Present Only 2021 (hence this represents NEW Development) Present in 2000 and 2021 (hence NO NEW Development; Unchanged) Present Only 2000 (One may opt to ignore this category or investigate it further. The MVC is choosing to ignore this category at this time given the aerial photo resolution and polygon delineation techniques utilized when this circa 2000 dataset was developed - leading these areas, perhaps, to an inadvertent classification of 'developed' - &/or the analyst's definition of 'developed' may have been broader than that applied in the latter 2021 vegetation analysis.) NOTE: Since the MVC's 2021 dataset is under constant review and maintenance, this temporal analysis is subject to change. For use in ArcPro: A layer legend file for use with this dataset -- this might save you some time and aggravation.