Losing Ground 6, Annual Land Cover Products for Massachusetts.

This dataset consists of a set of annual land cover products for 1985-2017 produced using the CCDC algorithm as part of Mass Audubon's Losing Ground 6 analysis. 

The sixth edition of Mass Audubon’s Losing Ground series of reports builds on the methods first employed in Losing Ground 5. Following LG5 analysis, the Continuous Change Detection and Classification (CCDC) algorithm, a harmonic modeling approach, was used to identify land cover changes and characterizes the spectral-temporal properties of stable land cover “segments” based on dense time series of all high-quality Landsat observations (Zhu et al. 2012; Zhu and Woodcock 2014). However, the LG6 analysis improves on the training data and land cover labeling system used in LG5. For LG6, we developed a modified version of the MassGIS 2005 Land Use/Land Cover polygons and legend in an effort to provide greater thematic detail as well as increase the ecological relevancy of the mapped results. Integrating the CCDC approach and our detailed land cover training dataset, we produced a 30-year time series of land cover maps for the Massachusetts Mainland and Islands as well as offshore waters. The original maps generated by the CCDC algorithms were then manually post-processed to improve spatial accuracy of change detection results, and final results including post-processing steps are available here.

The Losing Ground 6 Classification includes the following land cover classes adapted from the 2005 MassGIS Land Use and 1m Impervious surface datasets:

> Man-made Built -- Greater than 25% constructed surfaces such as buildings, roads, parking lots, brick, asphalt, concrete 

> Man-made Bare -- Areas of man-made compacted soil or material such as mining or unpaved parking lots

> Natural Barren -- Natural occurring barren areas (i.e. rocky shores, sand, bare soil)

> Forest -- Pixels dominated by closed-canopy forest in leaf-on imagery, as well as mixed-cover pixels spanning forest edges that do not meet criteria for Built. 

> Forested Wetland -- Persistently vegetated wetlands dominated by tree cover; often found adjacent to rivers and in low-lying areas; Reference MassDEP Wetlands 

> Plantation -- Planted tree crops, includes orchards and tree farms

> Cultural grassland -- Dominated by herbaceous cover, includes pastures, fields, and row crops

> Irrigated herbaceous -- Heavily managed grass cover, includes golf courses and (non-synthetic) athletic fields

> Successional/transitional forest -- Forest recovering after stand-replacing disturbance; Predominantly (> 25%) shrub cover, and some immature trees not large or dense enough to be classified as forest. It also includes areas that are more permanently shrubby, such as heath areas, wild blueberries or mountain laurel.

> Managed shrubland -- Woody vegetation maintained in a mid-successional state, e.g. powerline corridors; includes "self-managed" stable shrublands, e.g. coastal shrub/heathland (e.g. scrub oak)

> Open water -- Dominated by open-water conditions, little to no seasonal vegetation cover

> Non-forested wetland -- Persistently or seasonally vegetated wetlands with little to no tree cover; Includes freshwater emergent and shrub swamp wetland types; Reference MassDEP Wetlands

> Saltwater wetland -- Coastal wetlands, often herbaceous-dominated marsh and may show signs of ditching; Reference MassDEP Wetlands

> Active cranberry bog -- active and recently active cranberry bogs; notable red color and geometric patch shapes

A more complete description of training sources, class labels and codes, and definitions is available here.

Please contact Dr. Valerie Pasquarella (valpasq@bu.edu) with any questions regarding these data and potential use cases.