C-CAP Land Cover, United States Virgin Islands, St Thomas, 2007

Date that the source FGDC record was last modified.

Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using 'fgdc_to_inport_xml.pl' script. Contact Tyler Christensen (NOS) for details.

Partial upload of Positional Accuracy fields only.

Partial upload to move data access links to Distribution Info.

NOAA OCM | Source Geospatial Form: remote-sensing image | Type of Source Media: DVD/CD-ROM

This dataset was created by Sanborn (www.sanborn.com).

This version of the classification is the High Resolution Land Cover (2007-era) for the Island of St Thomas, United States Virgin Islands.

This section outlines the classification procedure for St Thomas, United States Virgin Islands High Resolution C-CAP. ADS40 imagery and the 2003-era C-CAP classification were used in producing this land cover product. The mapping approach utilized a boundary summary and refinement procedure developed by Sanborn to leverage the 2003-era classification. A calibration visit was conducted and training data was collected for classification. Non impervious features were mapped using a 0.5 acre minimum mapping unit (MMU).

Pre-processing steps:

The ADS40 was provided to Sanborn as a geo-referenced product. Sanborn perfomed a quality control on the imagery to check for pixel dropouts and other image issues. Individual image tiles were

combined to create a single mosaic for the entire island. In conjunction with the ADS40 mosaic, Sanborn used Quickbird collected from 2002-2005 and LiDAR collected in 2007 for the island.

Field-Collected Data:

Training data was collected in the field between May 31th and June 5th, 2009. Land cover observations were recorded by analysts. The referenced dataset went through a QA/QC procedure to ensure it met accuracy standards.

Classification:

Segmentation - Image segmentation was completed at multiple scales using the multispectral (2.4 m) imagery in order to group like spectral and textural objects within the imagery. For consistency, the associated impervious data set was incorporated into the segmentation layer as a boundary delimiter. Segments can share boundaries of an impervious surface,

but can never overlap an impervious surface.

Automated Classification - Logical rulesets and thresholding based on the spectral properties of the imagery, and ancillary data, and the early date classification were used to generate a mask of potential change. The change

mask was incorporated into the early date classification to create the 2007 classification.

Automated Classification Refinement - Models are built to refine or reclassify land cover areas by utilizing the wealth of attribute information linked to each segment within Definiens.

Classification Edits - As with any automated or semi-automated land cover classification there are often inconsistencies in the land cover map. The final step before map finalization was to remove inaccuracies through manual segment labeling as interpreted by an analyst.

Map Finalization - Sanborn used independent reviewer's comments to further refine the land cover map.

Attributes for this product are as follows:

0 Background

1 Unclassified

2 Impervious

3

4

5 Developed, Open Space

6 Cultivated Crops

7 Pasture/Hay

8 Grassland/Herbaceous

9 Deciduous Forest

10 Evergreen Forest

11 Mixed Forest

12 Scrub/Shrub

13 Palustrine Forested Wetland

14 Palustrine Scrub/Shrub Wetland

15 Palustrine Emergent Wetland

16 Estuarine Forested Wetland

17 Estuarine Scrub/Shrub Wetland

18 Estuarine Emergent Wetland

19 Unconsolidated Shore

20 Bare Land

21 Open Water

22 Palustrine Aquatic Bed

23 Estuarine Aquatic Bed

24 Tundra

25 Snow/Ice

Metadata imported