lidarwatermsk

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Reference_Information
• Distribution_Information

Identification_Information:

Citation:

Citation_Information:

Originator: U.S. Geological Survey

Publication_Date: Unpublished Material

Publication_Time: Unknown

Title: lidarwatermsk

Edition: First

Geospatial_Data_Presentation_Form: vector digital data

Online_Linkage:

Description:

Abstract:

Preliminary polygons generated to delineate over-water returns of topographic lidar collected by TerraPoint in South San Francisco Bay in May of 2004.

Purpose:

The purpose is to mask out the lidar returns which were collected over water. The values collected over water are not accurate reflections of water levels and should be eliminated from any terrain models generated from this data.

Supplemental_Information:

Vector polygon boundaries were generated by interpretation of georeferenced IKONOS satellite imagery, hillshaded full-feature lidar DEMs, and lidar return intensity. All digitizing was conducted using the "heads up" on screen method. Accuracy is not guaranteed. If you discover any errors with this dataset please report them to Amy Foxgrover (afoxgrover@usgs.gov) The poly_mask attribute differentiates between polygon classifications.

poly_mask = water1 is water areas (either within the bay or ponds) which should be removed from any elevation models.

poly_mask = lidar are areas of valid lidar data surrounded by areas of water (data islands). Such areas include marsh, tidal flats, and features within salt ponds. This data should be retained in elevation models.

poly_mask = water2 are areas of water that fall within the above describe 'data islands' of valid lidar data surrounded by water. This consists of channels within marsh islands. These areas should be removed from elevation models.

For additional information of how these polygons were created see Foxgrover, A.C. and Jaffe, B.E., 2005, South San Francisco Bay 2004 Topographic Lidar Survey: Data Overview and preliminary Quality Assessment: U.S. Geological Survey Open-File report 2005-1284, 57 p. [URL: <http://pubs.usgs.gov/of/2005/1284/>]

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: unknown

Status:

Progress: Preliminary

Maintenance_and_Update_Frequency: As needed

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -122.371617

East_Bounding_Coordinate: -121.924463

North_Bounding_Coordinate: 37.708916

South_Bounding_Coordinate: 37.407467

Keywords:

Theme:

Theme_Keyword_Thesaurus:

REQUIRED: Reference to a formally registered thesaurus or a similar authoritative source of theme keywords.

Theme_Keyword: lidar

Theme_Keyword: topography

Place:

Place_Keyword: South San Francisco Bay

Access_Constraints: None

Use_Constraints:

Please recognize the U.S. Geological Survey (USGS) as the source of this information. Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials.

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Amy Foxgrover

Contact_Organization: U.S. Geological Survey

Contact_Position: Geographer

Contact_Voice_Telephone: (831) 427-4743

Contact_Electronic_Mail_Address: afoxgrover@usgs.gov

Native_Data_Set_Environment:

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Vector polygon boundaries were generated by interpretation of georeferenced IKONOS satellite imagery, hillshaded full-feature lidar DEMs, and lidar return intensity. All digitizing was conducted using the "heads up" on screen method. The poly_mask attribute differentiates between polygon classifications.

poly_mask = water1 is water areas (either within the bay or ponds) which should be removed from any elevation models.

poly_mask = lidar are areas of valid lidar data surrounded by areas of water (data islands). Such areas include marsh, tidal flats, and features within salt ponds. This data should be retained in elevation models.

poly_mask = water2 are areas of water that fall within the above describe 'data islands' of valid lidar data surrounded by water. This consists of channels within marsh islands. These areas should be removed from elevation models.

Lineage:

Process_Step:

Process_Description:

A 1 m grid of bare earth lidar intensity returns was generated using the pointgrid command in ArcInfo. The average intensity was calculated using a focal mean over a 3 x 3 m neighborhood. This intensity grid, in conjunction with full-feature hill-shaded lidar and IKONOS satellite imagery was used to delineate areas of water.

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Grid_Coordinate_System:

Grid_Coordinate_System_Name: Universal Transverse Mercator

Universal_Transverse_Mercator:

UTM_Zone_Number: 10

Transverse_Mercator:

Scale_Factor_at_Central_Meridian: 0.999600

Longitude_of_Central_Meridian: -123.000000

Latitude_of_Projection_Origin: 0.000000

False_Easting: 500000.000000

False_Northing: 0.000000

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair

Coordinate_Representation:

Abscissa_Resolution: 0.000018

Ordinate_Resolution: 0.000018

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 6378137.000000

Denominator_of_Flattening_Ratio: 298.257222

Distribution_Information:

Distributor:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Eric Zhang

Contact_Organization: San Francisco Estuary Institute

Contact_Voice_Telephone: (510) 746-7361

Contact_Electronic_Mail_Address: ericz@sfei.org

Resource_Description: Downloadable Data

Distribution_Liability:

Please recognize the U.S. Geological Survey (USGS) as the source of this information. Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. Any use of trade, product, or firm names is for deescriptive purposes only and does not imply endorsement by the U.S. Government. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Transfer_Size: 0.412