Historical Time-series Classification of Habitat for 1957, 1980 and 2015 in the Nisqually River Delta, Washington

We produced time-series classifications of habitat, photosynthetic pathway functional types and species in the Nisqually River Delta for the years 1957, 1980, and 2015. Using an object-oriented approach in eCognition 9 software, we performed a hierarchical classification on historical and current imagery to identify change within the watershed and wetland ecosystems. Imagery used to created these maps included panchromatic aerial photographs from 1957, a 3-band color infrared aerial photograph from 1980, and for the 2015 classification we used an 8-band multispectral satellite image and a 4-band color infrared image from 2014. Data pre-processing included image georeferencing, atmospheric correction, and image mosaicking. For all classifications, our rule-set approach utilized hierarchical processing that alternated between image segmentation and threshold-based classification. Image segmentation was performed using the multi-resolution segmentation tool which uses weighted spectral, brightness, and textural features to create image objects. Scale parameters were determined through trial and error to find appropriate object sizes based on hierarchical level and class type. Habitat maps were created for each time period, while dominant species and photosynthetic functional type maps were limited to the 1980 and 2015 years due to insufficient spectral information. Dominant species classes for 1980 were based on a plant associations in a 1975 vegetation map by Burg et al. 1980, while the 2015 species classes were determined by 2015 species field observations. For the photosynthetic functional type classes, salt grass was assign to the C4 class, while other emergent marsh species were C3. Change maps were made between each time period to quantify change for emergent marsh vegetation, forest, and photosynthetic functional types.

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  "010:12"
]

[
  "geospatial"
]