(Version 4.1, updated September 13, 2013) Maritime limits for the United States are measured from the U.S. baseline, recognized as the low-water line along the coast as marked on NOAA's nautical charts in accordance with the articles of the Law of the Sea. The baseline and related maritime limits are reviewed and approved by the interagency U.S. Baseline Committee. The primary purpose of this dataset is to update the official depiction of these maritime limits and boundaries on NOAA's nautical charts. The Office of Coast Survey depicts on its nautical charts the territorial sea (12 nautical miles), contiguous zone (24nm), and exclusive economic zone (200nm, plus maritime boundaries with adjacent/opposite countries). U.S. maritime limits are ambulatory and subject to revision based on accretion or erosion of the charted low water line. For more information about U.S. Maritime Limits and Boundaries and to stay up-to-date, see: http://www.nauticalcharts.noaa.gov/csdl/mbound.htm. For the full FGDC metadata record, see: http:www.ncddc.noaa.gov/approved_recs/nos_de/ocs/ocs/MB_ParentDataset.html. Coordinates for the US/Canada international boundary, on land and through the Great Lakes, are managed by the International Boundary Commission.

The US territorial sea is a maritime zone, over which the United States exercises sovereignty. Each coastal State claims a territorial sea that extends seaward up to 12 nautical miles from its coastal baseline. As defined by maritime law, the coastal State exercises sovereignty over its territorial sea, the air space above it, and the seabed and subsoil beneath it. The U.S. territorial sea extends 12 nautical miles from the coastal baseline. The zone is usually used in concert with several other Limits and Boundary Lines for Maritime purposes.Maritime limits for the United States are measured from the US baseline, which is recognized as the low-water line along the coast as marked on NOAA's nautical charts. The baseline and related maritime limits are reviewed and approved by the interagency US Baseline Committee. The Office of Coast Survey depicts on its nautical charts the territorial sea (12nm), contiguous zone (24nm), and exclusive economic zone (200nm, plus maritime boundaries with adjacent/opposite countries. US maritime limits are ambulatory and subject to revision based on accretion or erosion of the charted low water line. Dataset SummaryThis map service contains data from NOAA and BOEM sources that address USA Regional coastal areas and are designed to be used together within an ArcGIS.com web map. These include: World Exclusive Economic Zone (EEZ) from NOAA Office of Coast SurveyContiguous Zone (CZ) from NOAA Office of Coast SurveyTerritorial Sea (TS) Boundary from NOAA Office of Coast SurveyRevenue Sharing Boundary [Section 8(g) of OCSLA Zone Boundary] from Bureau of Ocean Energy Management (BOEM)Submerged Land Act Boundaries (SLA) aka State Seaward Boundary (SSB)State Administrative Boundary from Bureau of Ocean Energy Management (BOEM)Continental Shelf Boundary (CSB) from Bureau of Ocean Energy Management (BOEM)Regional Maritime Planning Area Boundaries from NOAA Office of Coast SurveyInternational Provisional Maritime Boundary from NOAA (International Boundary Commission)The data for this layer were obtained from MarineCadastre.gov and is updated regularly.More information about U.S. Maritime Limits and BoundariesLink to source metadataWhat can you do with this layer?The features in this layer are used for areas and limits of coastal planning areas, or offshore planning areas, applied within ArcGIS Desktop and ArcGIS Online. A depiction of the territorial sea boundaries helps disputing parties reach an agreement as in the case of one state's boundary overlapping with another state's territorial sea, in which case the border is taken as the median point between the states' baselines, unless the states in question agree otherwise. A state can also choose to claim a smaller territorial sea.Conflicts still occur whenever a coastal nation claims an entire gulf as its territorial waters while other nations only recognize the more restrictive definitions of the UN convention. Two recent conflicts occurred in the Gulf of Sidra where Libya has claimed the entire gulf as its territorial waters and the US has twice enforced freedom of navigation rights, in the 1981 and 1989 Gulf of Sidra incidents.This layer is a feature service, which means it can be used for visualization and analysis throughout the ArcGIS Platform. This layer is not editable.

The Digital Geologic Map of International Boundary and Water Commission Mapping in Amistad National Recreation Area, Texas and Mexico is composed of GIS data layers complete with ArcMap 9.3 layer (.LYR) files, two ancillary GIS tables, a Map PDF document with ancillary map text, figures and tables, a FGDC metadata record and a 9.3 ArcMap (.MXD) Document that displays the digital map in 9.3 ArcGIS. The data were completed as a component of the Geologic Resources Inventory (GRI) program, a National Park Service (NPS) Inventory and Monitoring (I&M) funded program that is administered by the NPS Geologic Resources Division (GRD). Source geologic maps and data used to complete this GRI digital dataset were provided by the following: Eddie Collins, Amanda Masterson and Tom Tremblay (Texas Bureau of Economic Geology); Rick Page (U.S. Geological Survey); Gilbert Anaya (International Boundary and Water Commission). Detailed information concerning the sources used and their contribution the GRI product are listed in the Source Citation sections(s) of this metadata record (ibwc_metadata.txt; available at http://nrdata.nps.gov/amis/nrdata/geology/gis/ibwc_metadata.xml). All GIS and ancillary tables were produced as per the NPS GRI Geology-GIS Geodatabase Data Model v. 2.1. (available at: http://science.nature.nps.gov/im/inventory/geology/GeologyGISDataModel.cfm). The GIS data is available as a 9.3 personal geodatabase (ibwc_geology.mdb), and as shapefile (.SHP) and DBASEIV (.DBF) table files. The GIS data projection is NAD83, UTM Zone 14N. The data is within the area of interest of Amistad National Recreation Area.

Advances in data availability, Earth observation technologies, and geospatial sciences have transformed our ability to map Global Surface Water Extents (GSWE). However, traditional GSWE mapping has been limited to static estimates, with more recent efforts focusing on annual averages and temporal attributes like frequency and occurrence of long-term variations. We harnessed remotely sensed Sentinel-2 based near real-time Dynamic World land cover product to produce the first public, routinely available 10-meter resolution global surface water datasets. Our key contribution is an Open Science operational framework to rapidly extract the latest available Dynamic World products every 2-5 days, run geospatial analytics, and create actionable water information for educators, researchers, and stakeholders at any scale of practical interest.

This dataset has been developed by the Hydrology & Hydroinformatics Innovation Lab at the University of Texas at Arlington, United States.

This dataset contains maps of the location and temporal distribution of surface water from 1984 to 2020 and provides statistics on the extent and change of those water surfaces. For more information see the associated journal article: High-resolution mapping of global surface water and its long-term changes (Nature, 2016) and the online Data Users Guide.

These data were generated using 4,453,989 scenes from Landsat 5, 7, and 8 acquired between 16 March 1984 and 31 December 2020. Each pixel was individually classified into water / non-water using an expert system and the results were collated into a monthly history for the entire time period and two epochs (1984-1999, 2000-2020) for change detection.

This mapping layers product consists of 1 image containing 7 bands. It maps different facets of the spatial and temporal distribution of surface water over the last 35 years. Areas where water has never been detected are masked.

land and atmosphere. The European Space Agency is now studying concepts for the Next Generation Sentinel-3 Topography mission (S3NGT) mission that would launch in the 2032+ time period. In order to meet the primary objectives of the S3NGT mission requirement document a complex analysis of river and lake targets is required to size the satellite mass memory and downlink system.

Global map of open permanent water bodies at 300m spatial resolution derived from the full ENVISAT-ASAR dataset between 2005 and 2010.

In an attempt to improve the characterization of inland water bodies in global LC products, a SAR-based approach has been implemented. Multi-temporal acquisitions of Envisat ASAR Wide Swath Mode with local gap fillers based on Image Mode and Global Monitoring Mode from the years 2005 to 2010, MERIS data and auxiliary datasets have been used to generate a single epoch map of permanent open water bodies at 300 m.

Static map of stable open water bodies at 300m spatial resolution resulting from a land/water classification based on Envisat ASAR, SRTM-SWBD and MERIS data. The water pixels of this map correspond to the class "Water Bodies" of the CCI-LC Maps.

The product consists of 3 layers:

Map land/permanent water classification at 300m spatial resolution. Legend : 1-Land, 2-Water,
NObsImsWS number of observations originating from the ASAR Wide Swath Mode + Image Monitoring Mode imagery,
NObsImsGM number of observations originating from the ASAR global monitoring mode imagery.

The collection of water quality data has been an integral part of the International Boundary and Water Commission's mission and goal since the signing of the 1944 Water Treaty. The IBWC collects water quality data for several transboundary rivers, the Rio Grande, Colorado River, New River, Alamo River, and the Tijuana River, along with stations in the Pacific Ocean known as the South Bay Ocean Outfall Water Quality Monitoring Program (Pacific Ocean). The data is collected and exchanged between the United States and Mexico as agreed to under the IBWC 1944 Water Treaty and the subsequent agreements made by the IBWC to implement the various water quality monitoring programs along the border. Water quality goals for each program are either specified in an IBWC Minute (such as Minute No. 264 for New River), or compared to water quality standards using United States or Mexican standards for rivers and streams.

In June 2000 the Geological Survey of Ireland (GSI) under the auspices of the Department of Public Enterprise (later moved to the Department of Communications, Marine and Natural Resources in 2002) awarded a contract to Global Ocean Technologies Limited (GOTECH) to undertake the Irish National Seabed Survey (INSS), Zone 3 Hydrographic Survey. This area, of some 413,760 square Kilometres, stretches from the 200 metre water depth line on the Western Seaboard of Ireland, westward into the full oceanic depths of the Atlantic Ocean. The INSS mapped to approximately the 200m contour. The project was completed in 2006.The INFOMAR programme is a joint venture between Geological Survey Ireland (GSI) and Marine Institute (MI) and is the successor to the Irish National Seabed Survey. INFOMAR aims to survey the remaining shelf and coastal waters between 2006 to 2026.It is a vector dataset. Vector data portrays the world using points, lines and polygons (areas). The zone data is shown as polygons. Each polygon holds information on the zone number, zone part, area (km2) and perimeter (m).The United Nations Convention on the Law of the Sea (UNCLOS), also called the Law of the Sea Convention or the Law of the Sea Treaty, is an international agreement that establishes a legal framework for all marine and maritime activities. Articles 3 and 4 of UNCLOS sets out what a territorial sea is and what is permitted. Territorial sea, as defined by the 1982 United Nations Convention on the Law of the Sea (UNCLOS), is a belt of coastal waters extending at most 12 nautical miles (22 km; 14 mi) from the baseline (usually the mean low-water mark) of a coastal state. The territorial sea is regarded as the sovereign territory of the state, although foreign ships (military and civilian) are allowed innocent passage through it, or transit passage for straits; this sovereignty also extends to the airspace over and seabed below. Adjustment of these boundaries is called, in international law, maritime delimitation.A state's territorial sea extends up to 12 nm (22 km; 14 mi) from its baseline. A nautical mile is 1,852 metres. If this would overlap with another state's territorial sea, the border is taken as the median point between the states' baselines, unless the states in question agree otherwise. A state can also choose to claim a smaller territorial sea.It is a vector dataset. Vector data portrays the world using points, lines and polygons (areas). The data is shown as a line.The exclusive economic zone is an area beyond and adjacent to the territorial sea, subject to the specific legal regime established in this Part, under which the rights and jurisdiction of the coastal State and the rights and freedoms of other States are governed by the relevant provisions of this Convention. An exclusive economic zone, as prescribed by the 1982 United Nations Convention on the Law of the Sea, is an area of the sea in which a sovereign state has exclusive rights regarding the exploration and use of marine resources, including energy production from water and wind.It stretches from the outer limit of the territorial sea (22.224 Km or 12 NM from the baseline) out to a maximum of 370.4 Km (or 200 nautical miles) from the coast of the state in question. It is also referred to as a maritime continental margin and, in colloquial usage, may include the continental shelf. The term does not include either the territorial sea or the continental shelf beyond the 200 nautical mile limit. The difference between the territorial sea and the exclusive economic zone is that the first confers full sovereignty over the waters, whereas the second is merely a "sovereign right" which refers to the coastal state's rights below the surface of the sea. The surface waters are international waters.It is a vector dataset. Vector data portrays the world using points, lines and polygons (areas). The data is shown as a line.The United Nations Convention on the Law of the Sea (UNCLOS), also called the Law of the Sea Convention or the Law of the Sea Treaty, is an international agreement that establishes a legal framework for all marine and maritime activities. Article 76 of UNCLOS sets out the definition of what the continental shelf is and what is permitted. The Geoscience Regulatory Office (GSRO) (formerly Petroleum Affairs Division (PAD)) a division of the Department of the Environment, Climate and Communications (DECC) has statutory responsibility for Ireland’s Continental Shelf.A state wishing to extend its shelf beyond 200 nautical miles must make a submission to the Commission on the Limits of the Continental Shelf. Ireland’s continental shelf physically extends beyond 200 nautical miles to the west and south of the country and, working together, the Departments of Foreign Affairs and of the Environment, Climate and Communications have in all made three submissions to the Commission – in 2005 in relation to the Porcupine Abyssal Plain, then jointly with France, Spain and the UK for the seabed of the Celtic Sea and Bay of Biscay, and finally for the Hatton Rockall area of the North East Atlantic in 2009.The submission concerning the Porcupine Abyssal Plain successfully resulted in the addition of 39,000 km² of seabed to the State’s continental shelf. The Commission has also made recommendations that would enclose an area of approx. 80,000 km² of seabed in the Celtic Sea and Bay of Biscay and the division of this area is currently under negotiation between the four countries concerned. In addition, regular discussions have taken place for a number of years between Ireland and the UK (who agreed continental shelf boundaries in 1988), Iceland and the Faroe Islands in relation to overlapping claims in the North East Atlantic.It is a vector dataset. Vector data portrays the world using points, lines and polygons (areas). The data is shown as a line.

An exclusive economic zone (EEZ) is a sea zone prescribed by the United Nations Convention on the Law of the Sea over which a sovereign state has special rights over the exploration and use of marine resources, including energy production from water and wind. This maritime boundary is designed to be used with other marine boundaries in order to help determine areas of trade, commerce and transportation. The 200 NM zone is measured country-by-country from the baseline maritime boundary (usually, but not in all cases, the mean low-water mark used is not the same thing as the coast line). For each country, we've obtained the official list of the baseline points from the United Nations under Maritime Space.The exclusive economic zone stretches much farther into sea than the territorial waters, which end at 12 NM (22 km) from the coastal baseline (if following the rules set out in the UN Convention on the Law of the Sea). Thus, the EEZ includes the contiguous zone. States also have rights to the seabed of what is called the continental shelf up to 350 NM (648 km) from the coastal baseline, beyond the EEZ, but such areas are not part of their EEZ. The legal definition of the continental shelf does not directly correspond to the geological meaning of the term, as it also includes the continental rise and slope, and the entire seabed within the EEZ. The chart below diagrams the overlapping jurisdictions which are part of the EEZ. When the (EEZ) boundary is between countries which are separated by less than 200NM is settled by international tribunals at any arbitrary line. Many countries are still in the process of extending their EEZs beyond 200NM using criteria defined in the United Nations Convention on the Law of the Sea. Dataset Summary The data for this layer were obtained from https://www.marineregions.org/. Link to source metadata.Preferred Citation: VLIZ (2014). Maritime Boundaries Geodatabase, version 8. Available online at http://www.marineregions.org/. Consulted on 2015-03-28.These limits and boundaries were created for NOAA's internal purposes only to update the charted maritime limits and maritime boundaries on NOAA charts. These limits and boundaries do not represent the official depiction. For official depiction, please see NOAA's paper or raster nautical charts (Sourced from NOAA_Version 4.1, 9/10/2013). Also, this map service contains data from NOAA and BOEM sources and the VLIZ (2014) Maritime Boundaries Geodatabase, version 8. Available online at Marineregions.org. Consulted on 2014-12-02.What can you do with this layer?Within its EEZ, a coastal country has: (a) sovereign rights for the purpose of exploring, exploiting, conserving and managing natural resources, whether living or nonliving, of the seabed and subsoil and the superjacent waters and with regard to other activities for the economic exploitation and exploration of the zone, such as the production of energy from the water, currents and winds; (b) jurisdiction as provided for in international law with regard to the establishment and use of artificial islands, installations, and structures, marine scientific research, and the protection and preservation of the marine environment, and (c) other rights and duties provided for under international law.The features in this layer can be used for showing areas and limits of sovereignty, revenue sharing, for siting a renewable energy project, for commerce routes, and for vessel transportation tracking within ArcGIS Desktop and ArcGIS Online. An example application of the layers is listed below, from the Marine Cadastre site. If, by example, a renewable energy project is located within state waters, the rules of leasing for that particular state will apply (and therefore vary by state), and no revenues will go to the federal government.If any portion of the project location falls within the federal 8(g) zone, then 27 percent of the revenues collected by the federal government will be shared with those states whose coastlines are within 15 miles of the geographic center of the project area. If the shoreline of more than one state is within 15 miles of the geographic center of the project, all the states will share the revenue payments in proportion to the inverse distance of the nearest points of their respective coastlines to the geographic center of the project. See more on this topic at U.S.C. and C.F.R. If the location is entirely in federal waters seaward of the 8(g) zone, no collected revenues will go to the state(s).This layer is a feature service, which means it can be used for visualization and analysis throughout the ArcGIS Platform. This layer is not editable.

The International Map of the World (IMW) series is no longer maintained, and printed copies of this map are no longer available. The Australian portion of the series consists of 49 maps. They were produced to an international specification using the R502 series at 1:250,000 scale as source material. Production commenced in 1926 and was completed in 1978. The maps were revised from time to time and the last reprint was undertaken in 2003. Each standard map sheet covers 4 degrees of latitude by 6 degrees of longitude and was produced using a Lambert Conformal Conic projection with 2 standard parallels. The series has recently been superseded by the 1:1 000 000 topographic map general reference.

NOAA is responsible for depicting on its nautical charts the limits of the 12 nautical mile Territorial Sea, 24 nautical mile Contiguous Zone, and 200 nautical mile Exclusive Economic Zone (EEZ). The outer limit of each of these zones is measured from the U.S. normal baseline, which coincides with the low water line depicted on NOAA charts and includes closing lines across the entrances of legal bays and rivers, consistent with international law. The U.S. baseline and associated maritime limits are reviewed and approved through the interagency U.S. Baseline Committee, which is chaired by the U.S. Department of State. The Committee serves the function of gaining interagency consensus on the proper location of the baseline using the provisions of the 1958 Convention on the Territorial Sea and the Contiguous Zone, to ensure that the seaward extent of U.S. maritime zones do not exceed the breadth that is permitted by international law. In 2002 and in response to mounting requests for digital maritime zones, NOAA launched a project to re-evaluate the U.S. baseline in partnership with other federal agencies via the U.S. Baseline Committee. The focus of the baseline evaluation was NOAA's largest scale, most recent edition nautical charts as well as supplemental source materials for verification of certain charted features. This dataset is a result of the 2002-present initiative and reflects a multi-year iterative project whereby the baseline and associated maritime limits were re-evaluated on a state or regional basis. In addition to the U.S. maritime limits, the U.S. maritime boundaries with opposite or adjacent countries as well as the US/Canada International Boundary (on land and through the Great Lakes) are also included in this dataset. Direct data download | Metadata NOAA OCS U.S. Maritime Limits & Boundaries

World Water Bodies provides a detailed basemap layer for the lakes, seas, oceans, large rivers, and dry salt flats of the world.

World Water Bodies represents the open water rivers, lakes, dry salt flats, seas, and oceans of the world.For complete hydrographic coverage, use this dataset in conjunction with the World Linear Water dataset.

Last Revised: February 2016

Map Information

This nowCOAST™ time-enabled map service provides maps depicting the latest global forecast guidance of water currents, water temperature, and salinity at forecast projections: 0, 12, 24, 36, 48, 60, 72, 84, and 96-hours from the NWS/NCEP Global Real-Time Ocean Forecast System (GRTOFS). The surface water currents velocity maps display the direction using white or black streaklets. The magnitude of the current is indicated by the length and width of the streaklet. The maps of the GRTOFS surface forecast guidance are updated on the nowCOAST™ map service once per day. For more detailed information about layer update frequency and timing, please reference the
nowCOAST™ Dataset Update Schedule.

Background Information

GRTOFS is based on the Hybrid Coordinates Ocean Model (HYCOM), an eddy resolving, hybrid coordinate numerical ocean prediction model. GRTOFS has global coverge and a horizontal resolution of 1/12 degree and 32 hybrid vertical layers. It has one forecast cycle per day (i.e. 0000 UTC) which generates forecast guidance out to 144 hours (6 days). However, nowCOAST™ only provides guidance out to 96 hours (4 days). The forecast cycle uses 3-hourly momentum and radiation fluxes along with precipitation predictions from the NCEP Global Forecast System (GFS). Each forecast cycle is preceded with a 48-hr long nowcast cycle. The nowcast cycle uses daily initial 3-D fields from the NAVOCEANO operational HYCOM-based forecast system which assimilates situ profiles of temperature and salinity from a variety of sources and remotely sensed SST, SSH and sea-ice concentrations. GRTOFS was developed by NCEP/EMC/Marine Modeling and Analysis Branch. GRTOFS is run once per day (0000 UTC forecast cycle) on the NOAA Weather and Climate Operational Supercomputer System (WCOSS) operated by NWS/NCEP Central Operations.

The maps are generated using a visualization technique developed by the Data Visualization Research Lab at The University of New Hampshire's Center for Coastal and Ocean Mapping (http://www.ccom.unh.edu/vislab/). The method combines two techniques. First, equally spaced streamlines are computed in the flow field using Jobard and Lefer's (1977) algorithm. Second, a series of "streaklets" are rendered head to tail along each streamline to show the direction of flow. Each of these varies along its length in size, color and transparency using a method developed by Fowler and Ware (1989), and later refined by Mr. Pete Mitchell and Dr. Colin Ware (Mitchell, 2007).

Time Information

This map service 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.

In addition to ArcGIS Server REST access, time-enabled OGC WMS 1.3.0 access is also provided by this service.

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.

This service is configured with time coverage support, meaning that the service will always return the most relevant available data, if any, to the specified time value. For example, if the service contains data valid today at 12:00 and 12:10 UTC, but a map request specifies a time value of today at 12:07 UTC, the data valid at 12:10 UTC will be returned to the user. This behavior allows more flexibility for users, especially when displaying multiple time-enabled layers together despite slight differences in temporal resolution or update frequency.

When interacting with this time-enabled service, only a single instantaneous time value should be specified in each request. If instead a time range is specified in a request (i.e. separate start time and end time values are given), the data returned may be different than what was intended.

Care must be taken to ensure the time value specified in each request falls within the current time coverage of the service. Because this service is frequently updated as new data becomes available, the user must periodically determine the service's time extent. However, due to software limitations, the time extent of the service and map layers as advertised by ArcGIS Server does not always provide the most up-to-date start and end times of available data. Instead, users have three options for determining the latest time extent of the service:

  Issue a returnUpdates=true request (ArcGIS REST protocol only)
  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 the REST Service 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 referred 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™ LayerInfo Help Documentation

References

Fowler, D. and C. Ware, 1989: Strokes for Representing Vector Field Maps. Proceedings: Graphics Interface '98 249-253. Jobard, B and W. Lefer,1977: Creating evenly spaced streamlines of arbitrary density. Proceedings: Eurographics workshop on Visualization in Scientific Computing. 43-55. Mitchell, P.W., 2007: The Perceptual optimization of 2D Flow Visualizations Using Human in the Loop Local Hill Climbing. University of New Hampshire Masters Thesis. Department of Computer Science. NWS, 2013: About Global RTOFS, NCEP/EMC/MMAB, College Park, MD (Available at http://polar.ncep.noaa.gov/global/about/). Chassignet, E.P., H.E. Hurlburt, E.J. Metzger, O.M. Smedstad, J. Cummings, G.R. Halliwell, R. Bleck, R. Baraille, A.J. Wallcraft, C. Lozano, H.L. Tolman, A. Srinivasan, S. Hankin, P. Cornillon, R. Weisberg, A. Barth, R. He, F. Werner, and J. Wilkin, 2009: U.S. GODAE: Global Ocean Prediction with the HYbrid Coordinate Ocean Model (HYCOM). Oceanography, 22(2), 64-75. Mehra, A, I. Rivin, H. Tolman, T. Spindler, and B. Balasubramaniyan, 2011: A Real-Time Operational Global Ocean Forecast System, Poster, GODAE OceanView –GSOP-CLIVAR Workshop in Observing System Evaluation and Intercomparisons, Santa Cruz, CA.

Data supporting the publication:Cuthbert et al (2019). Global patterns and dynamics of climate–groundwater interactions. Nature Climate Change, 9, 137–141. DOI:10.1038/s41558-018-0386-4https://www.nature.com/articles/s41558-018-0386-4See the ReadMe file uploaded with the data and the Methods section of the paper for details of the derivation of each dataset.

The World Hydro Basemap service is designed to be used as a base map by scientists, professionals, and researchers in the fields of Hydrology, Geography, Climate, Soils, and other natural sciences. The map features a hydro-centric design based on the amount of water flowing within the drainage network such that symbols of the same size and color represent roughly the same amount of water. This map shows surface water flow as a linear phenomenon even over and through bodies of water. Using the best available data we show relative flow accurately, so that if one river carries more water downstream than another river, the result will be that the river will have a thicker symbol on the map. This map is a mashup of the World Hydro Reference overlay, and the World Terrain base, which allows you to sandwich in content such as thematic services like soil units, vegetation, or ecoregions. This basemap provides a frame of reference for showing regional, national, and continental hydrologic phenomena such as drought, runoff, river level monitoring and flood forecasting.River names are collected in the UTF8 character set, so river names are collected in their original language, but are written in the Roman alphabet. Sources for all river names are from the open source geonames.org project so they are international by nature.The map is compiled from several sources. The global scales (very small scales through 1:2,300,000) include content from: HydroSHEDS, GTOPO30 Global Topographic Data, SRTM, GLWD, WorldClim, GRDC, and WWF Global 200 Terrestrial Eco Regions, with the latter three providing the inputs and basis for calculating flow. At medium scales (1:36,000 to 1:2,000,000) this service currently contains only U.S. data from the NHDPlusV2 that was jointly produced by the USGS and EPA. This work is licensed under the Web Services and API Terms of Use. View Summary | View Terms of Use HydroSHEDSThis product, the World Hydro Basemap, incorporates data from the HydroSHEDS database which is © World Wildlife Fund, Inc. (2006-2012) and has been used herein under license. WWF has not evaluated the data as altered and incorporated within the World Hydro Basemap, and therefore gives no warranty regarding its accuracy, completeness, currency or suitability for any particular purpose. Portions of the HydroSHEDS database incorporate data which are the intellectual property rights of © USGS (2006-2008) (data available from U.S. Geological Survey, EROS Data Center, SD), NASA (2000-2005), ESRI (1992-1998), CIAT (2004-2006), UNEP-WCMC (1993), WWF (2004), Commonwealth of Australia (2007), and Her Royal Majesty and the British Crown and are used under license. The scientific citation for the HydroSHEDS database is: Lehner, B., Verdin, K., Jarvis, A. (2008): New global hydrography derived from spaceborne elevation data. Eos, Transactions, AGU, 89(10): 93-94.

The Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Water Bodies Database (ASTWBD) Version 1 data product provides global coverage of water bodies larger than 0.2 square kilometers at a spatial resolution of 1 arc second (approximately 30 meters) at the equator, along with associated elevation information.

The ASTWBD data product was created in conjunction with the ASTER Global Digital Elevation Model (ASTER GDEM) Version 3 data product by the Sensor Information Laboratory Corporation (SILC) in Tokyo. The ASTER GDEM Version 3 data product was generated using ASTER Level 1A scenes acquired between March 1, 2000, and November 30, 2013. The ASTWBD data product was then generated to correct elevation values of water body surfaces.

To generate the ASTWBD data product, water bodies were separated from land areas and then classified into three categories: ocean, river, or lake. Oceans and lakes have a flattened, constant elevation value. The effects of sea ice were manually removed from areas classified as oceans to better delineate ocean shorelines in high latitude areas. For lake water bodies, the elevation for each lake was calculated from the perimeter elevation data using the mosaic image that covers the entire area of the lake. Rivers presented a unique challenge given that their elevations gradually step down from upstream to downstream; therefore, visual inspection and other manual detection methods were required.

The geographic coverage of the ASTWBD extends from 83°N to 83°S. Each tile is distributed in GeoTIFF format and referenced to the 1984 World Geodetic System (WGS84)/1996 Earth Gravitational Model (EGM96) geoid. Each data product is provided as a zipped file that contains an attribute file with the water body classification information and a DEM file, which provides elevation information in meters.

Several layers describing density of surface water / streams projected to the Good Homolosine projection. List of layers included:

• hyd_log1p.upstream.area_merit.hydro_m = Upstream Drainage Area based on the MERIT Hydro,
• hyd_river.density_gloric_p = rasterized Global River Classification (GLORIC) DB,
• lcv_water.occurance_jrc.surfacewater_p = Surface Water based on the JRC's Global Surface Water,
• lcv_water.seasonal_probav.glc.lc100_p = Seasonal Inland Water probability based on the Copernicus LC100 map,
• lcv_wetlands.cw_upmc.wtd_c = composite wetland (CW) map based on Tootchi et al. (2019),
• Goode_Homolosine_domain_250m.tif = map domain prepared by Luís de Sousa,
• tiles_GH_100km_land.gpkg = 100 km x 100 km tiling system covering the land mass,

Important notes: Processing steps are described in detail here. Antartica is not included. Reprojecting maps to Goode Homolosine projection can be cumbersome and small amount of artifacts at the edges of the map can be anticipated.

These maps were develop in connection to the OpenLandMap.org initiative.

If you discover a bug, artifact or inconsistency in the maps, or if you have a question please use some of the following channels:

• Technical issues and questions about the code: https://gitlab.com/openlandmap/global-layers/issues
• General questions and comments: https://disqus.com/home/forums/landgis/

All files internally compressed using "COMPRESS=DEFLATE" creation option in GDAL. File naming convention:

• hyd = theme: hydrology and water dynamics,
• log1p.upstream.area = variable: log(X+1)*10 of the upstream area,
• merit.hydro = determination method: MERIT Hydro,
• m = mean value,
• 250m = spatial resolution / block support: 250 m,
• b0..0cm = vertical reference: surface,
• 2017 = time reference: period 2017,
• v0.1 = version number: 0.1,

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Many maps of open water and wetland have been developed based on three main methods: (i) compiling national/regional wetland surveys; (ii) identifying inundated areas by satellite imagery; (iii) delineating wetlands as shallow water table areas based on groundwater modelling. The resulting global wetland extents, however, vary from 3 to 21% of the land surface area, because of inconsistencies in wetland definitions and limitations in observation or modelling systems. To reconcile these differences, we propose composite wetland (CW) maps combining two classes of wetlands: (1) regularly flooded wetlands (RFW) which are obtained by overlapping selected open-water and inundation datasets; (2) groundwater-driven wetlands (GDW) derived from groundwater modelling (either direct or simplified using several variants of the topographic index). Wetlands are thus statically defined as areas with persistent near saturated soil because of regular flooding or shallow groundwater. To explore the uncertainty of the proposed data fusion, seven CW maps were generated at the 15 arc-sec resolution (ca 500 m at the Equator) using geographic information system (GIS) tools, by combining one RFW and different GDW maps. They correspond to contemporary potential wetlands, i.e. the expected wetlands assuming no human influence under the present climate. To validate the approach, these CW maps were compared to existing wetland datasets at the global and regional scales: the spatial patterns are decently captured, but the wetland extents are difficult to assess against the dispersion of the validation datasets. Compared to the only regional dataset encompassing both GDWs and RFWs, over France, the CW maps perform well and better than all other considered global wetland datasets. Two CW maps, showing the best overall match with the available evaluation datasets, are eventually selected. They give a global wetland extent of 27.5 and 29 million km², i.e. 21.1 and 21.6% of global land area, which is among the highest values in the literature, in line with recent estimates also recognizing the contribution of GDWs. This wetland class covers 15% of global land area, against 9.7% for RFWs (with an overlap ca 3.4 %), including wetlands under canopy/cloud cover leading to high wetland densities in the tropics, and small scattered wetlands, which cover less than 5% of land but are very important for hydrological and ecological functioning in temperate to arid areas. […]