C-CAP Land Cover Change, Commonwealth of the Northern Mariana Islands (CNMI), Anatahan, 2005 - 2016

Date that the source FGDC record was last modified.

Converted from FGDC Content Standard 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 NOAA's Ocean Service, Office for Coastal Management (OCM).

This dataset contains the classifications of 2005 imagery and 2016 imagery. It is used for change analysis between these years. The attributes include a from-to change description category. There are 481 classes corresponding to the 481 possible from-to change combinations. In this section of the metadata, the 2005 classification procedure is described, then the 2016 change detection classification procedure is described. Finally in the post-processing section, the process of combining the maps to generate a spatial matrix of change is discussed.The 2005 dataset was created by Sanborn (www.sanborn.com).

This version of the classification is the High Resolution Land Cover (2005-era) for the Island of Anatahan, CNMI.

This section outlines the classification procedure for the Island of Anatahan, CNMI High Resolution C-CAP. This island has no man-made impervious surfaces, thus an impervious layer was not created. The mapping approach utilized a boundary summary and refinement procedure developed by Sanborn to leverage previous United States Forest Service mapping efforts to create the high resolution land cover data set. 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 Quickbird mosaic utilized for this project was provided from Digital Globe as an orthorectifed, georeferenced product and was consistent with the quoted 1:12000 spatial accuracy.

Field-Collected Data:

Training data was collected in the field between March 14th and 27th, 2008. 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, Image segments are classified using a decision tree classifier in See5 software and an iterative nearest neighbor classifier in Definiens software. Nearest neighbor training data is collected through analyst interpretation or ancillary data sets and used to calibrate the classification algorithm.

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 Acquatic Bed

For the 2016 land cover, areas of change were identified in the 2016 imagery and the changes were added to the 2005 land cover to create the 2016 land cover.

Post-Processing Steps:

A GIS matrix algorithm was run with 2005 and 2016 datasets as inputs. The algorithm generates

a from-to file where each combination is uniquely labeled from 1 to 481.