State of Hawaii, Office of Planning, 20071130, Impervious Surfaces, Island of Kauai: NOAA's Ocean Service, Coastal Services Center (CSC), Charleston, SC.Online Links:
This is a Raster data set. It contains the following raster data types:
Planar coordinates are encoded using Row and Column
Abscissae (x-coordinates) are specified to the nearest 2.400000
Ordinates (y-coordinates) are specified to the nearest 2.400000
Planar coordinates are specified in meters
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is Geodetic Reference System 80.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257224.
| Value | Definition |
|---|---|
| 0 Pervious | Features which allow infiltration from precipitation. |
| 1 Impervious | Anthropogenic features such as buildings, parking lots and roads developed from asphalt, concrete or other constructed surfaces which do not allow infiltration from precipitation. |
Sanborn 455 E. Eisenhower Parkway, Suite 270 Ann Arbor, Michigan 48108
808 587 2895 (voice)
808 587 2899 (FAX)
jdelos_santos@dbedt.hawaii.gov
To create a baseline inventory of impervious surfaces which can be utilized by state and local resource managers to assess the impacts precipitation events on water quality and flooding.
www.sanborn.com., Sanborn., 20070515, Island of Kauai Impervious Surfaces Map.: State of Hawaii, Office of Planning, Honolulu, HI.Online Links:
Person who carried out this activity:
808 587 2895 (voice)
808 587 2899 (FAX)
jdelos_santos@dbedt.hawaii.gov
Treating the map as a binary or single class scheme, impervious/pervious, allows for a simpler sampling technique than a traditional thematic land cover assessment. For this product, Sanborn developed an efficient procedure to assess accuracy of the impervious classification. The desired accuracy is at least 85% for the impervious/pervious map of Kauai. The approach described here tested the map for an accuracy of 90% for a MMU of 0.06 acre. Since Sanborn was working with a two-case situation they only needed to know whether the classification was right or wrong, a binomial distribution was used to calculate the sample size. Using that assumption, Sanborn used Ginevan (1979) who illustrated a sampling method using stratified random points that satisfies three criteria: 1. The scheme should have a low probability of accepting a map of low accuracy. 2. It should have a high probability of accepting a map of high accuracy. 3. It should require a minimum number of ground truth samples. Using the look-up table given in the paper that presents the required sample size for a given minimum error and a desired level of confidence, Sanborn determined the specific number of points that are required to meet the accuracy specification. To validate a map to determine if it meets a thematic accuracy of 90%, with a 95% confidence level (a 95% confidence interval means the chance of 1 in 20 of rejecting a map that is actually correct), the minimum number of sites required was 298; with the map being rejected if more than 21 are misclassified. In order to compensate for the rarity of impervious surfaces over a large portion of the Kauai landscape, the approach was to create 3 strata layers in order to limit the selection process to areas of likely impervious, and produce a map that accurately assesses the usefulness of the map to the user. Strata 1: Impervious Features This strata layer is based on the actual classification of impervious features. Strata 2: Distance buffer from impervious map The presence of impervious surfaces are correlated with other impervious features, and are likely to occur near other impervious features. A distance map based on a buffer of 250 m will be used to sample from. Strata 3: Remaining un-sampled area. Each of the strata was sampled to build an assessment database that exceeds the required minimum of 298 assessment points. The goal for the division of accuracy assessment points was an approximate 50:50 (impervious:pervious) stratification. The break down is as follows. Table 1: Sampling breakdown based on strata layer. Strata Layer Percentage of Total Samples Target Number of Samples Impervious Classification 30 >149 Distance From Impervious feature Mask 25 >75 Remaining Un-sampled Area 25 >74 Areas of impervious or where impervious surfaces are expected were biased in the sampling structure. Once the samples are collected, labeling and quality control procedures were completed on the samples to create a final accuracy database. The result was a simplified confusion matrix where only two classes are categorized. An overall accuracy statement can be made by summing the correct accuracy locations and deriving a percentage relative to the total number of accuracy points. References Congalton, R.G., Kass Green 1999. Assessing the accuracy of remotely sensed data: principles and practices. CRC/Lewis Press, Boca Raton, FL. (In Press) Congalton, R. G. and R. D. Macleod. 1998. A quantitative comparison of change-detection algorithms for monitoring eelgrass from remotely sensed data. Photogrammetric Engineering and Remote Sensing. Vol. 64, No. 3, March 1998, pp. 207-216. Ginevan, M.E. 1979. Testing land-use map accuracy: another look. Photogrammetric Engineering and Remote Sensing, 45(10): 1371-1377.
Accuracy dependant on source data
Not applicable
Data set is complete.
Tests for logical consistency indicate that all row and column positions in the selected latitude/longitude window contain data. Conversion and integration with vector files indicates that all positions are consistent with earth coordinates covering the same area. Attribute files are logically consistent.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Use_Constraints:
- Although every effort has been made to ensure the accuracy of information, errors and conditions originating from physical sources used to develop the State of Hawaii GIS database may be reflected in the data supplied. The user must be aware of data conditions and bear responsibility for the appropriate use of the information with respect to possible errors, original map scale, collection methodology, currency of data, and other conditions specific to certain data. The GIS data or cartographic digital files are not a legal representation of any of the features which they depict. No warranty expressed or implied is made by State of Hawaii GIS program regarding the accuracy or utility of this information.
(843)740-1210 (voice)
(843)740-1224 (FAX)
clearinghouse@noaa.gov
Downloadable Data
Users must assume responsibility to determine the usability of these data.
| Data format: | ERDAS Imagine image file (.img) Size: 30 |
|---|---|
| Network links: |
<ftp://ftp.csc.noaa.gov/pub/crs/ccap/high_res/HI/hi_kauai_2005_ccap_hr_impervious.zip> |
| Media you can order: |
CD-ROM
(format ISO 9660)
Note: ISO 9660 format allows the CD-ROM to be read by most computer operating systems.
|
808 587 2895 (voice)
808 587 2899 (FAX)
jdelos_santos@dbedt.hawaii.gov