This dataset was created by Sanborn Mapping Company. This version of the classification is the late-date (2000-era). The study area is the Coastal zone 66 Region. An early-date (1995-era) classification is also available for the same area.
Summary:
This section outlines the classification procedure for the zone 66 C-CAP Late Date map. The three dates of imagery were first reviewed for image quality and shifts between image dates. Training points were used as the dependent variable in a CART (Classification Analysis by Regression Tree) approach. Derivative data layers (NDVI, Tasseled Cap) were calculated from the TM data and were used as additional independent variables in the analysis. There were 3 major versions of the map prior to a draft map: 1) the provisional map, 2) automated (incl. draft and final) and 3) final edited. The provisional map was developed prior to field work to give an idea of potential areas to sample. This rough map represented the first output from the CART classification routine. Ancillary data (DEMs, etc) and spectral data were used in this and all other CARTmodels. The final automated map had additional points from the field and photo interpretation added. Points were continually added until the best possible model was developed. This represented a fully automated product. This product was then altered by hand edits to refine the classification. In addition, a percent impervious data layer developed from TM data using high resolution imagery, was imbedded into the classification to define the developed classes. This produced the final-with-edits version which is the final version of the classification and is the one described here.
Pre-processing steps:
Each Landsat TM scene was geo-referenced by USGS (United States Geological Survey) EROS Data Center. The Sanborn staff reviewed the spectral and spatial quality of the imagery. Areas that were greater than 1-2 pixels off were sent back to USGS for reprocessing. The data was geo-referenced to Albers Conical Equal Area, with a
spheroid of GRS 1980, and Datum of NAD83. The data units is in meters. The zone 66 TM data was delivered in the form of USGS zone mosaics. The data included three dates of TM- leaf-on, leaf-off, and spring. For each date of TM, spectral and tasseled cap data were received.
Field-Collected Data:
The goals of the field data collection were to sample the diversity of the landscape, within the classes, and among
image dates. Classes that would be more difficult to collect from air photos were targeted for field data collection. To meet these goals, Sanborn stratified the image into spectral clusters and located the field sites throughout the study area based on these. In addition to these pre-arranged sites, Sanborn collected points while driving between locations. Due to limited time and accessibility, not all polygons were assessed in the field. Those that we did not visit on the ground were labeled with digital orthophotographs or Ikonos data if it was available. Both training and validation points were collected together. See the accuracy assessment section to see how the points were split into training and validation points. Sanborn used laptop computers and GPS (Global Positioning System) to correctly locate field points on the TM imagery. Software downloaded from the Minnesota's Department of Natural Resources (DNR) was used to connect the Garmin GPS to the laptop computer and ESRI's ArcView software.
Sanborn's programmer developed an ArcMap application that allowed entry of location and field notes with a click of the mouse. These data were stored in a shapefile. Items that were collected were:
Land Cover characterization
Special conditions and remarks
Photograph Number
Date/time location
The data and equipment used for the fieldwork are as follows:
Ancillary datasets:
TIGER 2000
NLCD - mosaicked into zones
State road map and Delorme state atlas www.delorme.com
Hardware: with ArcView/ArcGIS and data
GARMIN GPS modules and external antennae, redundant data
cables
Cameras devices (Floppy Drives, CD Burners, external HDD)
Extra batteries (lap-top and GPS)
Mobile phones
System backup CD's with data and software
Compass notebooks with instructions and road maps with
pre-determined routes Wetland and Vegetation Field Guides
Imagery:
Image data for each zone
Initial classifications
Classification:
After the field points for training were collected, they were combined with photo-interpreted points and used as
the dependent variable in a CART classification approach. Many layers tested as independent layers. They included three dates of spectral and tasseled cap imagery, DEM, slope, aspect, texture, band indices (NDVI, Moisture, NDVI-Green, shape indices fractal dimension, compactness, convexity, and form). Statistical analyses and visual inspection of the output was used to eliminate data that was redundant or not useful in the classification. Additional training points were added to help reduce some of the confusion between classes. The rough classification was created at the end of this process using only the CART discrete decision-tree software. A provisional classification was produced by applying spatial models using ancillary data to the rough classification. The final automated map was then edited using hand editing techniques while using high resolution imagery as reference data. Independently of this process, impervious data layers for Zone 66 were created. This layer was developed from Regression Tree and used impervious classifications from IKONOS imagery to predict pixel level percent impervious at the TM pixel level. The continuous percent impervious data was thresholded to produce the developed categories and imbedded into the final map.
Attributes for this product are as follows:
0 Background
1 Unclassified (Cloud, Shadow, etc)
2 High Intensity Developed
3 Medium Intensity Developed
4 Low Intensity Developed
5 Open Spaces Developed
6 Cultivated Land
7 Pasture/Hay
8 Grassland
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 Water
22 Palustrine Aquatic Bed
23 Estuarine Aquatic Bed
24 Tundra (N/A)
25 Snow/Ice (N/A)
Ancillary Datasets:
Non-TM image datasets used are DEM (Digital Elevation Model), slope, aspect, positional index, NWI, NLCD,
TIGER2000, field-collected points, photo-interpreted points, zone 66 GAP reclassified by NOAA (Gap Analysis
Program),Census data (housing and population density), Ecoregions.
QA/QC Process:
There were several QA/QC steps involved in the creation of this product. First, there was an internal QA/QC. This was done by viewing the classification frame-by-frame along with the TM imagery, the classification, and high
resolution reference imagery. NOAA staff completed a similar review and provided both general and point comments.