Biscayne Shipwrecks - Analyze Week

   In this week's lab, analysis was conducted on the benthic and bathymetric data from last week. Buffers and clipping was used to determine what type of benthic features could be found within 300 meters of the Heritage Trail shipwreck sites. The benthic and bathymetric data was further analyzed through reclassification in order to determine areas that could be potentially dangerous for ships to travel through. Finally, this reclassified data was ran through a weighted overlay analysis, combining both inputs together to create an output that displays potential areas for shipwreck locations.

300 meter buffer displaying benthic features around each site

Reclassified data

Weighted Overlay Model output

Supervised Classification

In this lab, a supervised classification of current land use in Germantown, Maryland was conducted using ERDAS Imagine. AOI signatures were selected by hand using the polygon tool and recorded in the Signature Editor dialog box. All signatures were analyzed through the Mean Plot tool to determine which bands provided the greatest difference between signatures. The bands 3, 4, and 5 provided the greatest difference in signatures and was set as the band combination to reflect the data best. The signatures were then run through the Supervised Classification tool, with an additional Distance File output to show if any signature features are likely to have the wrong classification (symbolized as bright spots). The Distance File is used as a reference for correcting any wrongly classified signatures. Lastly, the supervised image is recoded by consolidating the signatures to eight classes. Those classes are agriculture, deciduous forest, fallow field, grasses, mixed forest, roads, urban/residential, and water. The final output map was created through ArcMap.

Modeling Biscayne Shipwrecks - Prepare Week

   This week, we gathered data on shipwrecks in the Biscayne National Park. This data will be used to generate a weighted overlay model. Data gathered includes a historical nautical chart from 1892, a current ENC, and bathymetric data for the Biscayne Bay. The historical chart was downloaded from the NOAA's Historical Map and Chart Collection and georeferenced to the location. The bathymetric data was downloaded from the NOAA's National Geophysical Data Center and symbolized to reflect depth in meters (shallow in red, deep in blue).

Unsupervised Classification

   In this lab, an unsupervised classification was performed on an aerial image of the UWF campus, in ERDAS Imagine, using the Unsupervised Classification tool in the Raster tab. Afterward, the results of the unsupervised classification was further reclassified by condensing the original output of fifty color categories into just five color categories. These five categories are grass, trees, shadows, roads/buildings, and mixed surfaces. Mixed surfaces is classified as pixels that can be found across multiple surface types and can not be pinpointed to just one category.

   The total area of the campus is 232.26 hectares. Of that total, 142.735 ha (61%) was classified as permeable while 89.5237 ha (39%) was classified as impermeable. Permeable surfaces consisted of the categories grass, trees, and shadows. While some shadows covered impermeable surfaces, the majority covered permeable surfaces. Impermeable surfaces consisted of roads/buildings and mixed. While some mixed surfaces covered permeable areas, the majority covered impermeable surfaces.