Contours 5Ft NOAA IFSAR

	CCH GIS Data Dictionary
	Contours 5Ft NOAA IFSAR - island wide contours at 5 Ft intervals which were derived from the Interferometric Synthetic Aperture Radar (ifSAR) 5 meter post spacing digital terrain model obtained from NOAA. Verticle accuracy stated to be within 1.68 meters.

Metadata

ATTRIBUTES:

COLUMN NAME	DESCRIPTION	SAMPLE
Contour	elevation in ft	55

NOTES:

The base data from which these contours are derived were collected from Oct 16, 2005 to Oct 23, 2005.
Processing:
used Smooth Line, ArcTool command (PAEK, 20 feet), remove jagged appearance
used Simplify Line, ArcTool command (.5 Feet), improve performance

Note from NOAA on the IfSAR DTM source data used to create these contours: The fundamental vertical accuracy for the IfSAR-derived Digital Terrain Model (bare earth approximation) is 1.68 meters at the 95 percent confidence level. This means that points tested in open terrain (n=165) have a combined vertical RMSE of 0.86 meter (which meets our contract specification of 1 meter or less). The horizontal accuracy wasn't assessed (it usually isn't for LIDAR or IfSAR), but a low vertical RMSE usually means that the horizontal accuracy is good and we specified an accuracy of 5 meters or less in the SOW.

The important consideration with the fundamental vertical accuracy statement is that it represents only those points in open, flat terrain. The definition of "open" in this case includes areas that have an unobscured view of the sky in all directions above 10 degrees elevation, and do not have any multi-path or interference sources nearby.

The City and County of Honolulu encourages GIS data users to verify the suitability of the data before use. Please report any discrepancies or errors found to gis@honolulu.gov.

REFERENCES:

Information regarding the base data (DTM) that these contours were derived from:

IFSAR - interferometric synthetic aperture radar

View NOAA's digital surface model metadata record that these contours were generated from.

Visit the NOAA Pacific Coastal Services Center “Digital Coast” site or go directly to their Digital Access Viewer to download data for a chosen region.

Noaa: Data Notes and Considerations

Intermap: 3D Digital Elevation Model Product Sheet

Intermap's Nextmap Program: DTM v1.0 and v1.5 product sheet

COVERAGE:

Contours 5Ft NOAA IFSAR
Coverage is island wide.

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CCH GIS Data Dictionary

Contours 5Ft NOAA IFSAR - island wide contours at 5 Ft intervals which were derived from the Interferometric Synthetic Aperture Radar (ifSAR) 5 meter post spacing digital terrain model obtained from NOAA. Verticle accuracy stated to be within 1.68 meters.