Metadata: Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2018 Title: Greig Street point cloud from low-altitude aerial imagery from unmanned aerial systems (UAS) flights over of the Lake Ontario shoreline in the vicinity of Sodus Bay, New York in July 2017 (LAZ file) Edition: 1.0 Geospatial_Data_Presentation_Form: LAZ binary data Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9XQYCD0 Publication_Information: Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: https://doi.org/10.5066/P9XQYCD0 Online_Linkage: https://www.sciencebase.gov/catalog/item/5b1ee15be4b092d965254a53 Larger_Work_Citation: Citation_Information: Originator: Christopher R. Sherwood Originator: Sandra M. Brosnahan Originator: Seth D. Ackerman Originator: Jonathan Borden Originator: Ellyn T. Montgomery Originator: Elizabeth A. Pendleton Originator: Emily J. Sturdivant Publication_Date: 2018 Title: Aerial imagery and photogrammetric products from unmanned aerial systems (UAS) flights over the Lake Ontario shoreline at Sodus Bay, New York, July 12 to 14, 2017. Edition: 1.0 Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9XQYCD0 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: Suggested citation: Sherwood, C.R., Brosnahan, S.M., Ackerman, S.D., Borden, Jonathan, Montgomery, E.T., Pendleton, E.A., and Sturdivant, E.J., 2018, Aerial imagery and photogrammetric products from unmanned aerial systems (UAS) flights over the Lake Ontario shoreline at Sodus Bay, New York, July 12 to 14, 2017: U.S. Geological Survey data release, https://doi.org/10.5066/P9XQYCD0. Online_Linkage: https://doi.org/10.5066/P9XQYCD0 Online_Linkage: https://www.sciencebase.gov/catalog/item/5b0800a7e4b0ac450c99d116 Description: Abstract: Low-altitude (80-100 meters above ground level) digital images were obtained from a camera mounted on a 3DR Solo quadcopter, a small unmanned aerial system (UAS), along the Lake Ontario shoreline in New York during July 2017. These data were collected to document and monitor effects of high lake levels, including shoreline erosion, inundation, and property damage in the vicinity of Sodus Bay, New York. This data release includes images tagged with locations determined from the UAS GPS; tables with updated estimates of camera positions and attitudes based on the photogrammetric reconstruction; tables listing locations of the base stations, ground control points, and transect points; geolocated, RGB-colored point clouds; orthomosaic images; and digital elevation models for each of the survey regions. Collection of these data was supported by the Federal Emergency Management Agency, the State of New York Departments of State and Environmental Conservation, and the USGS Coastal and Marine Geology Program and was conducted under USGS field activity number 2017-042-FA. Purpose: These points provide the calculated XYZ (horizontal and vertical) coordinates and RGB (red-green-blue) values of the land surface during a mid-day low-tide on 14 July, 2017 in the Greig Street study area. The product was created to demonstrate the use of structure-from-motion (SfM) for coastal research and may be used to develop further datasets, such as the digital elevation models, geomorphic feature mapping, and land cover classification. Supplemental_Information: For more information about this field activity, see https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-042-FA. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20170714 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -76.986433 East_Bounding_Coordinate: -76.969400 North_Bounding_Coordinate: 43.273290 South_Bounding_Coordinate: 43.265003 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:5b1ee15be4b092d965254a53 Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: Woods Hole Coastal and Marine Science Center Theme_Keyword: WHCMSC Theme_Keyword: State of New York Department of State Theme_Keyword: State of New York Department of Environmental Conservation Theme_Keyword: Federal Emergency Management Agency Theme_Keyword: shoreline Theme_Keyword: lake level Theme_Keyword: 3DR Solo quadcopter Theme_Keyword: Ricoh GRII Theme_Keyword: low-altitude aerial imagery Theme_Keyword: aerial imagery Theme_Keyword: shoreline photographs Theme_Keyword: photographs Theme_Keyword: photos Theme_Keyword: UAS Theme_Keyword: Unmanned aerial system Theme_Keyword: lakeshore Theme_Keyword: points Theme_Keyword: point clouds Theme_Keyword: LAS Theme_Keyword: LAZ Theme_Keyword: field activity number 2017-042-FA Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: remote sensing Theme_Keyword: topography Theme_Keyword: aerial photography Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme_Keyword: inlandWaters Theme_Keyword: location Theme_Keyword: elevation Place: Place_Keyword_Thesaurus: None Place_Keyword: USA Place_Keyword: Great Lakes Place_Keyword: New York Place_Keyword: Lake Ontario Place_Keyword: Sodus, NY Place_Keyword: Sodus Point Place_Keyword: Sodus Bay Place_Keyword: Sodus Point Place_Keyword: Greig Street Access_Constraints: none Use_Constraints: Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Sandra Brosnahan Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: Massachusetts Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2265 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: sbrosnahan@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: https://www.sciencebase.gov/catalog/file/get/5b1ee15be4b092d965254a53/?name=2017042FA_GreigSt_PointCloud_browse.jpg Browse_Graphic_File_Description: Browse image of a portion of the point cloud generated from photogrammetry and low-altitude aerial images obtained with unmanned aerial systems (UAS). Browse_Graphic_File_Type: JPEG Data_Quality_Information: Logical_Consistency_Report: Coordinates recorded for each point describe discrete positions in space and the visual reflectance at the time of capture. Photoscan software determines the photos used in the construction of the products (Point Cloud, DEM and Orthomosaic) based on the ability to align the photo and the usability of valid tie points within an image. A tie point represents a point that the software determine to be common from one photo to the next. The camera locations CSV file (available in the larger work citation) indicates which photos were used to create the final products. This final point cloud was checked for accuracy only by rotating the point cloud to view from multiple angles to ensure that obvious spurious points do not cause artifacts in the derivative products (DEM and Orthomosaic). Although some outlying points were manually eliminated, there are still many points that likely do not represent ground features, but are instead artifacts generated by moving water surfaces and/or erroneous tie points. Photographs (available in the larger work citation) are the source for the photogrammetric products and are grouped according to region and flight number. Flights 23-27 were acquired on July 12 and are used in the Lake Bluffs project. Flights 28-35 were acquired on July 13. However, flights 27-30 are included in the Charles Point project, and flights 31-35 are in the Sodus North Project. Flights 36-40 were acquired on July 14 and are used in the Greig Street Project. Completeness_Report: This point cloud was constructed from 1235 of the 1640 loaded images from successful flights over the Greig Street survey area that were imported into the Greig Street photogrammetry project. Some images were eliminated automatically by the Agisoft Photoscan software during processing because they contained insufficient numbers of reliable tie points relating them to ground features visible in adjacent images. Many of the eliminated images contain views of mostly water or oblique views that included the horizon. All of the points generated by the software to form a dense cloud have been included in this data release. That includes points that likely do not represent ground features, but are instead artifacts generated by moving water surfaces and or erroneous tie points. These points are commonly eliminated through either automatic or manual classification, but have been retained to allow experimentation with point classification methods. The fully processed Photoscan project for Greig Street (used to create the subsequent DEM and orthomosaic) used 1235 of the original 1640 images and the dense point cloud contains more than 252 million points. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Horizontal positions of individual points for the point cloud were calculated by photogrammetric software and ground control points. There are several sources of potential error that affect the horizontal accuracy: 1. The horizontal error estimate provided by Agisoft Photoscan for the Greig Street project as a result of alignment, optimization, and ground control processing procedures is 9.91 cm. This value is an RMS estimate of positional error at discrete locations within the orthomosaic. 2. Ground control points were collected using a Spectra model SP80 GNSS receiver set to record XY locations with the national adjustment of 2011 (NAD83(2011) UTM zone 18N EPSG::6347), which differs from the Photoscan project coordinate system (NAD83/UTM zone 18N (EPSG::26918)). This difference may introduce an average additional 0.9 cm horizontally at the 95% confidence level according to the National Geodetic Survey (https://www.ngs.noaa.gov/web/surveys/NA2011/). 3. Additionally, an assessment of repeated survey sites including transect points and ground control points, using the same equipment by the USGS Aerial Imagery and Mapping (AIM) group estimates an accuracy of the ground control point locations of 1.76 cm (horizontal) and 0.54 cm (vertical). The combination of the potential horizontal error is on the order of 12.35 cm for the Greig Street products. Although some portions of the map may contain much larger errors, greater than 2 m horizontally, especially along the boundary of the project that are far from a ground control point, and across water bodies. The horizontal coordinate system for the Charles Point Point Cloud, DEM and Orthomosaic is NAD83/UTM zone 18N (EPSG::26918). It is also important to note: The UAS image locations are derived from a mRo GPS (u-Blox Neo-M8N / 3DR SOLO Upgrade), located on the UAS, which receives signals from GPS and GLONASS satellites in WGS84 (G1150) EPSG::7660. This location information is used by the Photoscan software to help with the initial alignment, however after photo alignment, these location data have no bearing on the project or the derivative product. Therefore the positional accuracy and potential errors of the GPS data attached to the input photographs is not propagated to the Photoscan project and therefore does not contribute to the overall horizontal accuracy of the products (Point Cloud, DEM and Orthomosaic). Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Vertical positions of individual points for the point cloud were calculated by photogrammetric software and ground control points. There are several sources of potential error that affect the vertical accuracy: 1. The vertical error estimate provided by Agisoft Photoscan for the Greig Street project as a result of alignment, optimization, and ground control processing procedures is 7.23 cm. This value is an RMS estimate of positional error at discrete locations within the orthomosaic. 2. Ground control points were collected using a Spectra model SP80 GNSS receiver that was receiving real-time differential corrections from a GNSS base station established in Sodus Bay NY. The Z heights were reference to the NAVD88 vertical datum. An assessment of repeated survey sites using the same equipment by the USGS Aerial Imagery and Mapping group estimates a potential accuracy error of the ground control point locations of 1.76 cm (horizontally) and 0.54 cm (vertically). The combination of the potential vertical error is on the order of 2.0 cm for the photogrammetric products. Although some portions of the map may contain much larger errors, greater than 20 m vertically, especially along the boundary of the project that are far from a ground control point, and across water bodies. The vertical datum for the Greig Street Point Cloud, DEM and Orthomosaic is NAVD88 (meters). It is also important to note: The UAS image locations are derived from a mRo GPS (u-Blox Neo-M8N / 3DR SOLO Upgrade), located on the UAS, which receives signals from GPS and GLONASS satellites in WGS84 (G1150) EPSG::7660. This location information is used by the Photoscan software to help with the initial alignment, however after photo alignment, these location data have no bearing on the project or the derivative product. Therefore the positional accuracy and potential errors of the GPS data attached to the input photographs is not propagated to the Photoscan project and therefore does not contribute to the overall vertical accuracy of the products (Point Cloud and DEM). Lineage: Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: unpublished material Title: Field geotagged aerial imagery (or whatever title you want) Type_of_Source_Media: raster digital images Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20170712 Ending_Date: 20170714 Source_Currentness_Reference: ground condition of when images were taken Source_Citation_Abbreviation: geotagged images Source_Contribution: These are the images geotagged in the field and used to produce the subsequent photogrammetric products. The images available from the larger work citation of this data release have updated geotag information. Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2018 Title: Ground control point and transect locations associated with images collected during unmanned aerial systems (UAS) flights over The Lake Ontario shoreline in the vicinity of Sodus Bay, New York in July 2017 Other_Citation_Details: available from the Larger Work citation of this dataset (Suggested citation: Sherwood, C.R., Brosnahan, S.M., Ackerman, S.D., Borden, Jonathan, Montgomery, E.T., Pendleton, E.A., and Sturdivant, E.J., 2018, Aerial imagery and photogrammetric products from unmanned aerial systems (UAS) flights over the Lake Ontario shoreline at Sodus Bay, New York, July 12 to 14, 2017: U.S. Geological Survey data release, https://doi.org/10.5066/P9XQYCD0.) Type_of_Source_Media: text data files Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20170712 Ending_Date: 20170714 Source_Currentness_Reference: ground condition of when images were taken Source_Citation_Abbreviation: GCPs Source_Contribution: The ground control points (GCPs; not transect points -- see metadata for more information) were used to geolocate the photogrammetric products Process_Step: Process_Description: Images imported into Photoscan (Agisoft Photoscan Professional v. 1.3.2) for the Lake Ontario projects were geotagged using Mission Planner Software (version 1.3.49). Point Clouds for the Lake Ontario projects were constructed using photogrammetry software (Agisoft Photoscan Professional v. 1.3.2) and digital images taken approximately 80 and 100 m above the ground on July 10 - 14, 2017, with a Ricoh GRII digital camera mounted in a 3DR Solo quadcopter operated the U.S. Geological Survey. This point cloud is the product from one of several photogrammetry projects from field activity 2017-042-FA. Four projects were used for flights in the vicinity of Sodus Bay on July 12, 13, and 14, 2017 (Lake Bluffs, Charles Point, Sodus North, and Greig Street). The projects combined images with ground control points to produce geolocated, colored (red-green-blue schema) point clouds. This point cloud, for the Lake Bluffs project, was created using a standard processing flow as described in the processing step below. Process_Date: 201709 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Woods Hole Coastal and Marine Science Center Contact_Person: Christopher R. Sherwood Contact_Position: Research Oceanographer Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: Massachusetts Postal_Code: 02543 Country: U.S.A. Contact_Voice_Telephone: 508-548-8700 x2269 Contact_Facsimile_Telephone: 508 457 2310 Contact_Electronic_Mail_Address: csherwood@usgs.gov Process_Step: Process_Description: The following steps make up the processing flow for creating this point cloud: 1. Geotagged images (see source citation) containing useful imagery from the survey area were imported into Agisoft Photoscan Professional v. 1.3.2 software using the “Add photos…” tool. Photos taken before and immediately after takeoff, photos taken immediately prior to and after landing, and photos with 100% water were not loaded into the project. Project coordinate system is set to EPSG::7660 WGS84 (G1150) geocentric coordinate system. 2. Using ”Convert”, the coordinate system of the images (called “cameras” in Photoscan) was converted from native latitude/longitude WGS84 (G1150) coordinate system to meters in NAD83/UTM zone 18N (EPSG::26918). 3. The photos were processed through an initial alignment and optimization procedure using the following settings: Alignment - Accuracy: “High”; Pair selection: “Reference”; Key point limit: 80,000; Tie point limit; 0 (unlimited). Adaptive camera model fitting option was selected. Optimization - Lens-calibration parameters f, cx, cy, k1, k2, k3, p1, and p2 were included; b1, b2, and higher-order parameters k4, p3, and p4 were not. 4. The sparse point cloud (also known as tie points; created as a result of photo alignment and optimization) was edited using an iterative error-reduction procedure to filter the data. This was done in several iterations of a process called "Gradual Selection" to first to reduce reconstruction uncertainty (to a unitless value of 10) and then projection accuracy (to a weighted value of 3). 5. Ground control points were created by first by letting the software automatically detect markers where it finds all of the 4-ft square black/white targets deployed (false targets that are sometimes detected were manually deleted). The automatically-generated marker labels were manually changed to match the names in the survey notes and GCP location files. 6. "Import markers” was used to load the GCP location files, which assigned coordinates (northing, easting, and elevation in UTM Zone 18 North meters in NAD83 and NAVD88 coordinate systems) from the location file to the detected markers. The locations of auto-detected markers were retained. 7. Another round of "Gradual Selection" was done to reduce the reprojection error (to a value of 0.3 pixels, unless more than 10% of the points would be removed). 8. A dense point cloud was then created with the parameters "High" quality and “Aggressive” depth filtering. 9. The dense point cloud was exported in LAZ format (2017-07-10_GreigSt_POINTS.laz) and was then both were renamed to the AIM data release filenaming standard (e.g. 2017042FA_GreigSt_PointCloud.laz). Process_Date: 20170913 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U. S. Geological Survey, Woods Hole Coastal and Marine Science Center Contact_Person: Christopher R. Sherwood Contact_Position: Research Oceanographer Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: Massachusetts Postal_Code: 02543 Country: U.S.A. Contact_Voice_Telephone: 508-548-8700 x2269 Contact_Facsimile_Telephone: 508 457 2310 Contact_Electronic_Mail_Address: csherwood@usgs.gov Process_Step: Process_Description: Added keywords section with USGS persistent identifier as theme keyword. Process_Date: 20200810 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Point Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 252,454,437 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Universal Transverse Mercator Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -75.00000 Latitude_of_Projection_Origin: 0.000 False_Easting: 500000.0000 False_Northing: 0.0000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.001 Ordinate_Resolution: 0.001 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: 298.257222101 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: North American Vertical Datum of 1988 (NAVD88) Altitude_Resolution: 0.001 Altitude_Distance_Units: meters Altitude_Encoding_Method: Explicit elevation coordinate included with horizontal coordinates Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: The attribute information associated with point cloud follows the LAZ file standard. Attributes include location (northing, easting, and elevation in the NAD83/UTM zone 18N (EPSG::26918) horizontal and NAVD88 vertical coordinate systems), color (red, blue, and green components), intensity, and classification. All points are classified as 0 (unclassified). Entity_and_Attribute_Detail_Citation: ASPRS (2013, https://www.asprs.org/committee-general/laser-las-file-format-exchange-activities.html) and Isenburg (2013, https://doi.org/10.14358/PERS.79.2.209) Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey - ScienceBase Contact_Address: Address_Type: mailing and physical address Address: Denver Federal Center, Building 810, Mail Stop 302 City: Denver State_or_Province: CO Postal_Code: 80225 Contact_Voice_Telephone: 1-888-275-8747 Contact_Electronic_Mail_Address: sciencebase@usgs.gov Resource_Description: This data release contains point cloud data in LAZ format (2017042FA_GreigSt_PointCloud.laz) and a browse graphic (2017042FA_GreigSt_PointCloud_browse.jpg). FGDC CSDGM metadata (2017042FA_GreigSt_PointCloud.xml) accompanies the data. Distribution_Liability: Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: LAZ Format_Information_Content: Unclassified point cloud in LAZ format and the associated FGDC CSDGM metadata in XML format. File_Decompression_Technique: Use LAStools (http://www.cs.unc.edu/~isenburg/lastools/) or LASzip (http://www.laszip.org) or mapping software that can read in a LAZ file. Transfer_Size: 2303 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://www.sciencebase.gov/catalog/item/5b1ee15be4b092d965254a53 Network_Resource_Name: https://www.sciencebase.gov/catalog/file/get/5b1ee15be4b092d965254a53 Network_Resource_Name: https://doi.org/10.5066/P9XQYCD0 Access_Instructions: To download the data, it is recommended that you go to the page containing the data and take advantage of the large file handler. The first link is to the page containing the data. The second is a direct link to download all data available from the page as a zip file. And the final link is to the publication landing page. Fees: none Technical_Prerequisites: This file requires software capable of opening binary LAZ files. Metadata_Reference_Information: Metadata_Date: 20240319 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Sandra Brosnahan Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: Massachusetts Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2265 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: whsc_data_contact@usgs.gov Contact_Instructions: The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240319) Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998