Map InformationThis nowCOAST updating map service provides maps depicting visible, infrared, and water vapor imagery composited from NOAA/NESDIS GOES-EAST and GOES-WEST. The horizontal resolutions of the IR, visible, and water vapor composite images are approximately 1km, 4km, and 4km, respectively. The visible and IR imagery depict the location of clouds. The water vapor imagery indicates the amount of water vapor contained in the mid to upper levels of the troposphere. The darker grays indicate drier air while the brighter grays/whites indicates more saturated air. The GOES composite imagers are updated in the nowCOAST map service every 30 minutes. For more detailed information about the update schedule, see: http://new.nowcoast.noaa.gov/help/#section=updatescheduleBackground InformationThe GOES map layer displays visible (VIS) and infrared (IR4) cloud, and water vapor (WV) imagery from the NOAA/ National Environmental Satellite, Data, and Information Service (NESDIS) Geostationary Satellites (GOES-East and GOES-West). These satellites circle the Earth in a geosynchronous orbit (i.e. orbit the equatorial plane of the Earth at a speed matching the rotation of the Earth). This allows the satellites to hover continuously over one position on the surface. The geosynchronous plane is about 35,800 km (22,300 miles) above the Earth which is high enough to allow the satellites a full-disc view of the Earth. GOES-East is positioned at 75 deg W longitude and the equator. GOES-West is located at 135 deg W and the equator. The two satellites cover an area from 20 deg W to 165 deg E. The images are derived from data from GOES' Imagers. An imager is a multichannel instrument that senses radiant energy and reflected solar energy from the Earth's surface and atmosphere. The VIS, IR4, and WV images are obtained from GOES Imager Channels 1, 4, and 3, respectively. The GOES raster images are obtained from NESDIS servers in geo-referenced Tagged-Image File Format (geoTIFF).Time InformationThis map is time-enabled, meaning that each individual layer contains time-varying data and can be utilized by clients capable of making map requests that include a time component.This particular service can be queried with or without the use of a time component. If the time parameter is specified in a request, the data or imagery most relevant to the provided time value, if any, will be returned. If the time parameter is not specified in a request, the latest data or imagery valid for the present system time will be returned to the client. If the time parameter is not specified and no data or imagery is available for the present time, no data will be returned.In addition to ArcGIS Server REST access, time-enabled OGC WMS 1.3.0 access is also provided by this service.Due to software limitations, the time extent of the service and map layers displayed below does not provide the most up-to-date start and end times of available data. Instead, users have three options for determining the latest time information about the service:Issue a returnUpdates=true request for an individual layer or for the service itself, which will return the current start and end times of available data, in epoch time format (milliseconds since 00:00 January 1, 1970). To see an example, click on the "Return Updates" link at the bottom of this page under "Supported Operations". Refer to the ArcGIS REST API Map Service Documentation for more information.Issue an Identify (ArcGIS REST) or GetFeatureInfo (WMS) request against the proper layer corresponding with the target dataset. For raster data, this would be the "Image Footprints with Time Attributes" layer in the same group as the target "Image" layer being displayed. For vector (point, line, or polygon) data, the target layer can be queried directly. In either case, the attributes returned for the matching raster(s) or vector feature(s) will include the following:validtime: Valid timestamp.starttime: Display start time.endtime: Display end time.reftime: Reference time (sometimes reffered to as issuance time, cycle time, or initialization time).projmins: Number of minutes from reference time to valid time.desigreftime: Designated reference time; used as a common reference time for all items when individual reference times do not match.desigprojmins: Number of minutes from designated reference time to valid time.Query the nowCOAST LayerInfo web service, which has been created to provide additional information about each data layer in a service, including a list of all available "time stops" (i.e. "valid times"), individual timestamps, or the valid time of a layer's latest available data (i.e. "Product Time"). For more information about the LayerInfo web service, including examples of various types of requests, refer to the nowCOAST help documentation at: http://new.nowcoast.noaa.gov/help/#section=layerinfoReferencesNOAA, 2013: Geostationary Operational Environmental Satellites (GOES). (Available at http://www.ospo.noaa.gov/Operations/GOES/index.html)A Basic Introduction to Water Vapor Imagery. (Available at http://cimss.ssec.wisc.edu/goes/misc/wv/wv_intro.html)CIMSS, 1996: Water Vapor Imagery Tutorial (Available at http://cimss.ssec.wisc.edu/goes/misc/wv/)