BOREAS Site and Area Geographic Coordinate Information Summary: In an effort to properly document the sites and areas where data were collected, personnel of the BOReal Ecosystem-Atmosphere Study (BOREAS) Information System (BORIS) obtained and compiled geographic coordinate and other site information from several sources throughout the experiment period. The final set of information is organized into two data sets that provide geographic coordinate and site characteristic information for single sites and corner coordinates for standard geographic areas. The data are stored in two text files as American Standard Code for Information Interchange (ASCII) characters. Contact Information: David Knapp Raytheon ITSS NASA GSFC Greenbelt, MD (301) 286-1424 (301) 286-0239 (fax) David.Knapp@gsfc.nasa.gov Jeffrey A. Newcomer Raytheon ITSS NASA GSFC Greenbelt, MD (301) 286-7858 (301) 286-0239 (fax) Jeffrey.Newcomer@gsfc.nasa.gov Methods: -------- For single sites, the original intent was to provide geographic coordinates and some overall site characteristic data for reference purposes. In practice, it is obvious from looking at the table of data that the information was not provided or determined in a consistent manner (e.g., the slope and aspect columns of the site data table do not contain any information). The individual site coordinates were determined by several methods. Some of them were derived from using various Global Positioning System (GPS) instrumentation while other site coordinates were determined from maps, verbal descriptions, and other records that gave some indication of where a site was located. To the extent possible, the sources of the geographic coordinates and other information are provided. Except for the accuracy of the GPS coordinates, which is approximately 10 meters, the accuracy of the other coordinates is variable. The corner coordinates for the larger areas were determined from available maps and then entered into the database. The coordinates for the areas around the tower sites were derived by defining a 2- by 2-km area around the accepted tower site location given in the site coordinate file. The coordinates in the single site data set are provided in 3 different coordinate systems Latitude/Longitude, BOREAS Grid, and Universal Transverse Mercator (UTM). The coordinates given for each of these values is based on the North American Datum of 1983 (NAD83). If the original coordinates were determined from GPS, they were typically reported in latitude/longitude. If the location came from some other source, the coordinates could have been converted to latitude/longitude. The BOREAS Grid is based on the ellipsoidal version of the Albers Equal Area Conic (AEAC) projection with parameters chosen specifically to cover the BOREAS Region. The AEAC projection was chosen because it is easy to derive grid cells of equal area. There is also very little spatial distortion over the study area, given the parameters that were chosen. The AEAC projection parameters were: Datum: NAD83 Ellipsoid: GRS80 or WGS84 Origin: 111.000° W 51.000° N Standard Parallels: 52° 30' 00" N 58° 30' 00" N Units of Measure: kilometers The UTM system is a standard mapping system by which the Earth’s surface is divided into 60 zones, each spanning 6 degrees of longitude. Each zone is given a number that universally identifies it as covering a certain range of longitudes on the globe. The equator is the latitude of origin for UTM coordinates. The longitude of origin for each UTM zone is a longitude meridian that runs through the center of the zone. The two UTM zones that cover most of the BOREAS Region are zones 13 and 14. These zones have the following parameters as Transverse Mercator projections: Zone 13 Zone 14 --------- --------- Datum: NAD83 NAD83 Ellipsoid: GRS80 or WGS84 GRS80 or WGS84 Origin: 105.000° W 0.000° N 99.000° W 0.000° N False Easting: 500,000.0 meters 500,000.0 meters False Northing: 0.0 0.0 Units of Measure: meters meters The coordinates provided in this data set are based on the NAD83 datum, which is the datum used when projecting on the WGS84 ellipsoid. This datum and ellipsoid are also used for locations reported by GPS instrumentation. The user should remember when transferring any of the coordinates provided here to a map that they are based on the NAD83 datum. Most maps indicate in the legend which datum was used. If you are plotting these coordinates on maps that use the NAD27 datum (and the corresponding Clarke 1866 ellipsoid) you will have to apply a correction to the coordinates to convert them from NAD83 to NAD27. The differences between the two datums result in shifts on the order of about 30 meters in the East-West direction, and about 220 meters in the North-South direction. Many commercial Geographic Information System (GIS) software packages are able to convert coordinates between NAD27 and NAD83. A software program developed by BORIS entitled ‘BOR_CORD’ is provided on the BOREAS CD-ROM set and enables conversions between the coordinate systems mentioned. Data File Descriptions: Data characteristics for the two components to this data set, single geographic site information and area corner coordinates, are defined in the companion data definition file (geocoord.def). The data files contain numerical and character fields of varying length separated by commas. The character fields are enclosed with a single apostrophe marks. There are no spaces between the fields. Sample data records are shown in the companion data definition file (geocoord.def). Data Access: Contact for Data Center/Data Access Information: These BOREAS data are available from the Earth Observing System Data and Information System (EOS-DIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The BOREAS contact at ORNL is: ORNL DAAC User Services Oak Ridge National Laboratory (865) 241-3952 ornldaac@ornl.gov ornl@eos.nasa.gov Procedures for Obtaining Data: BOREAS data may be obtained through the ORNL DAAC World Wide Web site at http://www-eosdis.ornl.gov/ or users may place requests for data by telephone, electronic mail, or fax. Output Products and Availability: Requested data can be provided electronically on the ORNL DAAC's anonymous FTP site or on various media including, CD-ROMs, 8-MM tapes, or diskettes. The complete set of BOREAS data CD-ROMs, entitled "Collected Data of the Boreal Ecosystem-Atmosphere Study", edited by Newcomer, J., et al., NASA, 1999, are also available. Document Information Written: 11-Feb-2000 Revised: 25-Feb-2000 BORIS Review: 14-Feb-2000 Geog_Coord.doc 04/02/00