Flood Risk and Vulnerability Analysis Project - Atlantic Climate ...

surrounding areas were also evaluated during the accuracy assessment to determine the
probable ground class.
4. See Recommendations section for improved training and verification data and processes
3.3.4.2 Accuracy Assessment Procedures
A grid of 100,000 points was distributed randomly throughout the study area. One hundred
(100) points per class were randomly selected and assessed for true on-the-ground land cover
using the 2.5 meter pan-sharpened imagery. Points falling on pixel edges, and points where
interpretation of true land cover was obscured were excluded.
3.3.4.3 Interpretation
Figure 3-4. Pan-sharpened natural color, multi-spectral, and classified
land cover example. Classified land cover is based on 10m resolution,
multi-spectral imagery (center) while the 2.5m natural color imagery (left)
was used to assess classification accuracy.
Figure 3-5 is referred to as a “standard error” or “confusion matrix” in a traditional accuracy
assessment based on land cover at the location of each point. Data columns represent actual
ground classes manually determined using 2.5 m pan-sharpened imagery. For example, 113
points were manually determined (by visually looking at the 2.5m pan-sharpened imagery) to be
located on forest. Rows represent the classified land cover at the location of each point. For
example, 103 points fell on land cover classified as forest. The values along the diagonals (in
green) represent agreement between the ground truth and classified values. Percent correct for
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