Watershed Boundary Dataset (WBD) adalah kumpulan data unit hidrologi (HU) gabungan yang komprehensif dan konsisten dengan kriteria nasional untuk pembatasan dan resolusi. Area ini
menentukan luas area drainase air permukaan ke suatu titik
kecuali di area pesisir atau tepi danau yang mungkin memiliki beberapa
outlet seperti yang dinyatakan oleh Federal Standards and Procedures for
the National Watershed Boundary Dataset.
Batas DAS ditentukan semata-mata berdasarkan prinsip hidrologi berbasis sains, tidak mendukung batas administratif atau project khusus, maupun program atau lembaga tertentu. Tujuan
menentukan HU untuk WBD adalah untuk menetapkan kerangka kerja batas
drainase dasar, yang memperhitungkan semua area daratan dan permukaan.
HU dibatasi pada skala 1:24.000 di Amerika Serikat yang berbatasan, skala 1:25.000 di Hawaii dan Karibia, dan skala 1:63.360 di Alaska, yang memenuhi Standar Akurasi Peta Nasional (NMAS). WBD direpresentasikan sebagai poligon yang menentukan batas HU. HU diberi Kode Unit Hidrologi (HUC) yang
berkisar dari 2 digit hingga 12 digit. Kode ini menjelaskan lokasi unit di negara dan tingkat unit. Jumlah digit dalam HUC terkait dengan 6 tingkat detail untuk WBD:
poligon tingkat yang lebih rendah mencakup area yang lebih besar daripada poligon tingkat yang lebih tinggi. Makin tinggi levelnya, makin banyak digit yang ada di HUC, karena level sebelumnya ada di dalamnya.
Atribut poligon WBD mencakup HUC, ukuran (dalam bentuk hektar dan kilometer persegi), nama, HUC hilir, jenis DAS, area yang tidak berkontribusi, dan modifikasi aliran. Atribut garis WBD berisi tingkat unit hidrologi tertinggi untuk setiap batas, informasi sumber garis, dan modifikasi aliran.
Nama
Tingkat
Digit
Kode HU
Wilayah
1
2
2
Subwilayah
2
4
4
Basin
3
6
6
Subbasin
4
8
8
Daerah Aliran Sungai
5
10
10
Sub-DAS
6
12
12
*Dihitung oleh penyedia data.
Skema Tabel
Skema Tabel
Nama
Jenis
Deskripsi
areaacres
STRING
Ukuran fitur dalam satuan acre
areasqkm
STRING
Ukuran fitur dalam kilometer persegi
gnis_id
STRING
Nomor unik untuk menghubungkan nama unit hidrologi dengan database nama GNIS (selalu kosong)
loaddate
STRING
Tanggal saat data dimuat ke dalam database penyedia resmi
metasumber
STRING
ID unik yang menautkan elemen ke tabel metadata
nama
STRING
Nama GNIS untuk area geografis tempat unit hidrologis berada
shape_area
STRING
Luas fitur dalam satuan internal kuadrat
shape_leng
STRING
Panjang fitur dalam unit internal
sourcedata
STRING
Ruang yang disediakan untuk deskripsi singkat tentang
jenis data dasar yang digunakan untuk memperbarui atau mengubah WBD saat ini
(selalu kosong)
sourcefeat
STRING
Mengidentifikasi induk fitur jika fitur
adalah hasil pemisahan atau penggabungan (selalu kosong)
sourceorig
STRING
Deskripsi agensi yang membuat data dasar yang digunakan untuk meningkatkan kualitas WBD (selalu kosong)
negara bagian
STRING
Mengidentifikasi Negara Bagian atau area terpencil yang mencakup atau berbatasan dengan unit hidrologi
tnmid
STRING
Kolom 40 karakter unik yang mengidentifikasi setiap elemen dalam database secara eksklusif
Upaya terkoordinasi antara United States Department of Agriculture-Natural
Resources Conservation Service (USDA-NRCS), United States Geological
Survey (USGS), dan Environmental Protection Agency (EPA). Watershed Boundary Dataset (WBD) dibuat dari berbagai sumber dari setiap negara bagian dan digabungkan menjadi lapisan nasional standar untuk digunakan dalam perencanaan strategis dan akuntabilitas. Watershed
Boundary Dataset for HUC# [Online WWW]. URL yang tersedia: (https://datagateway.nrcs.usda.gov)
[Diakses 22/04/2017].
FeatureView adalah representasi yang dipercepat dan hanya dapat dilihat dari
FeatureCollection. Untuk mengetahui detail selengkapnya, buka
dokumentasi FeatureView.
Watershed Boundary Dataset (WBD) adalah kumpulan data unit hidrologi (HU) gabungan yang komprehensif dan konsisten dengan kriteria nasional untuk pembatasan dan resolusi. Area ini menentukan luas area drainase air permukaan ke suatu titik, kecuali di area pesisir atau tepi danau yang mungkin memiliki beberapa saluran keluar seperti …
[null,null,[],[[["\u003cp\u003eThe USGS Watershed Boundary Dataset (WBD) provides comprehensive hydrologic unit data for the United States, defining surface water drainage areas.\u003c/p\u003e\n"],["\u003cp\u003eIt includes polygons representing watershed boundaries at multiple levels of detail, with attributes like HUC codes, size, and names.\u003c/p\u003e\n"],["\u003cp\u003eThe dataset is freely available for use and can be accessed through Earth Engine using provided code snippets for visualization and analysis.\u003c/p\u003e\n"],["\u003cp\u003eWBD follows a hierarchical system with 6 levels, ranging from regions to subwatersheds, identified by Hydrologic Unit Codes (HUCs) with varying digits.\u003c/p\u003e\n"],["\u003cp\u003eThe dataset was created by USDA-NRCS, USGS, and EPA, based on science-based hydrologic principles and national delineation criteria.\u003c/p\u003e\n"]]],["The Watershed Boundary Dataset (WBD), provided by the USGS, offers hydrologic unit (HU) data detailing surface water drainage areas. It's available from 2017-04-22 to 2017-04-23. HUs are classified using Hydrologic Unit Codes (HUCs) from 2 to 12 digits, indicating unit hierarchy and location. The dataset includes polygon attributes like size, name, and flow data, with detailed schema information and code snippets for use in Google Earth Engine.\n"],null,["# HUC08: USGS Watershed Boundary Dataset of Subbasins\n\nDataset Availability\n: 2017-04-22T00:00:00Z--2017-04-23T00:00:00Z\n\nDataset Provider\n:\n\n\n [United States Geological Survey](https://nhd.usgs.gov/wbd.html)\n\nTags\n:\n[hydrology](/earth-engine/datasets/tags/hydrology) [surface-ground-water](/earth-engine/datasets/tags/surface-ground-water) [table](/earth-engine/datasets/tags/table) [usgs](/earth-engine/datasets/tags/usgs) [water](/earth-engine/datasets/tags/water) [watershed](/earth-engine/datasets/tags/watershed) [wbd](/earth-engine/datasets/tags/wbd) \n\n#### Description\n\nThe Watershed Boundary Dataset (WBD) is a comprehensive\naggregated collection of hydrologic unit (HU) data consistent\nwith the national criteria for delineation and resolution. It\ndefines the areal extent of surface water drainage to a point\nexcept in coastal or lake front areas where there could be multiple\noutlets as stated by the [Federal Standards and Procedures for\nthe National Watershed Boundary Dataset](https://pubs.usgs.gov/tm/11/a3).\nWatershed boundaries are determined solely upon science-based\nhydrologic principles, not favoring any administrative boundaries\nor special projects, nor particular program or agency. The intent\nof defining HUs for the WBD is to establish a baseline drainage\nboundary framework, accounting for all land and surface areas.\n\nThe HUs are delineated at 1:24,000-scale in the conterminous\nUnited States, 1:25,000-scale in Hawaii and the Caribbean, and\n1:63,360-scale in Alaska, meeting the National Map Accuracy Standards\n(NMAS). WBDs are represented as polygons that define the boundary\nof the HUs. The HUs are given a Hydrologic Unit Code (HUC) that\nranges from 2 digits to 12 digits. These codes describe where\nthe unit is in the country and the level of the unit. The number\nof digits in a HUC is related to 6 levels of detail for the WBD:\nthe lower level polygons cover larger areas than higher level\nones. The higher the level, the more digits to the HUC, since\nprevious levels are nested in it.\n\nThe WBD polygons attributes\ninclude HUCs, size (in the form of acres and square kilometers),\nname, downstream HUC, type of watershed, non-contributing areas,\nand flow modifications. WBD line attributes contain the highest\nlevel of hydrologic unit for each boundary, line source information\nand flow modifications.\n\n| Name | Level | Digit | HU Code |\n|--------------|-------|-------|---------|\n| Region | 1 | 2 | 2 |\n| Subregion | 2 | 4 | 4 |\n| Basin | 3 | 6 | 6 |\n| Subbasin | 4 | 8 | 8 |\n| Watershed | 5 | 10 | 10 |\n| Subwatershed | 6 | 12 | 12 |\n\n\\*Calculated by the data provider.\n\n### Table Schema\n\n**Table Schema**\n\n| Name | Type | Description |\n|------------|--------|---------------------------------------------------------------------------------------------------------------------------|\n| areaacres | STRING | Size of the feature in acres |\n| areasqkm | STRING | Size of the feature in square kilometers |\n| gnis_id | STRING | A unique number to relate the name of the hydrologic unit to the GNIS names database (always empty) |\n| loaddate | STRING | Date when the data were loaded into the official provider database |\n| metasource | STRING | A unique identifier that links the element to the metadata tables |\n| name | STRING | GNIS name for the geographic area in which the hydrologic unit is located |\n| shape_area | STRING | Area of feature in internal units squared |\n| shape_leng | STRING | Length of feature in internal units |\n| sourcedata | STRING | A space provided for a brief description of the type of base data used to update or change the current WBD (always empty) |\n| sourcefeat | STRING | Identifies the parent of the feature if the feature is the result of a split or merge (always empty) |\n| sourceorig | STRING | Description of the agency that created the base data used to improve the WBD (always empty) |\n| states | STRING | Identifies the State(s) or outlying areas that the hydrologic unit falls within or touches |\n| tnmid | STRING | A unique 40-character field that identifies each element in the database exclusively |\n| huc8 | STRING | Unique hydrologic unit code |\n\n### Terms of Use\n\n**Terms of Use**\n\nMost U.S. Geological Survey (USGS) information resides\nin the public domain and may be used without restriction. Additional\ninformation on [Acknowledging or Crediting USGS as Information\nSource](https://www.usgs.gov/information-policies-and-instructions/crediting-usgs) is available.\n\n### Citations\n\nCitations:\n\n- Coordinated effort between the United States Department of Agriculture-Natural\n Resources Conservation Service (USDA-NRCS), the United States Geological\n Survey (USGS), and the Environmental Protection Agency (EPA). The\n Watershed Boundary Dataset (WBD) was created from a variety of\n sources from each state and aggregated into a standard national\n layer for use in strategic planning and accountability. Watershed\n Boundary Dataset for HUC# \\[Online WWW\\]. Available URL: (https://datagateway.nrcs.usda.gov)\n \\[Accessed 22/04/2017\\].\n\n### Explore with Earth Engine\n\n| **Important:** Earth Engine is a platform for petabyte-scale scientific analysis and visualization of geospatial datasets, both for public benefit and for business and government users. Earth Engine is free to use for research, education, and nonprofit use. To get started, please [register for Earth Engine access.](https://console.cloud.google.com/earth-engine)\n\n### Code Editor (JavaScript)\n\n```javascript\nvar dataset = ee.FeatureCollection('USGS/WBD/2017/HUC08');\n\nvar visualization = {\n color: '808080',\n strokeWidth: 1\n};\n\ndataset = dataset.draw(visualization);\n\nMap.setCenter(-105.861, 39.529, 7);\nMap.addLayer(dataset, null, 'Basins');\n```\n[Open in Code Editor](https://code.earthengine.google.com/?scriptPath=Examples:Datasets/USGS/USGS_WBD_2017_HUC08)\n\n### Visualize as a FeatureView\n\n\nA `FeatureView` is a view-only, accelerated representation of a\n`FeatureCollection`. For more details, visit the\n[`FeatureView` documentation.](/earth-engine/guides/featureview_overview)\n| **Important:** Earth Engine is a platform for petabyte-scale scientific analysis and visualization of geospatial datasets, both for public benefit and for business and government users. Earth Engine is free to use for research, education, and nonprofit use. To get started, please [register for Earth Engine access.](https://console.cloud.google.com/earth-engine)\n\n### Code Editor (JavaScript)\n\n```javascript\nvar fvLayer = ui.Map.FeatureViewLayer('USGS/WBD/2017/HUC08_FeatureView');\n\nvar visParams = {\n color: '808080',\n lineWidth: 1\n};\n\nfvLayer.setVisParams(visParams);\nfvLayer.setName('Basins');\n\nMap.setCenter(-105.861, 39.529, 7);\nMap.add(fvLayer);\n```\n[Open in Code Editor](https://code.earthengine.google.com/?scriptPath=Examples:Datasets/USGS/USGS_WBD_2017_HUC08_FeatureView) \n[HUC08: USGS Watershed Boundary Dataset of Subbasins](/earth-engine/datasets/catalog/USGS_WBD_2017_HUC08) \nThe Watershed Boundary Dataset (WBD) is a comprehensive aggregated collection of hydrologic unit (HU) data consistent with the national criteria for delineation and resolution. It defines the areal extent of surface water drainage to a point except in coastal or lake front areas where there could be multiple outlets as ... \nUSGS/WBD/2017/HUC08, hydrology,surface-ground-water,table,usgs,water,watershed,wbd \n2017-04-22T00:00:00Z/2017-04-23T00:00:00Z \n-14.69 -180 71.567 180 \nGoogle Earth Engine \nhttps://developers.google.com/earth-engine/datasets\n\n- [](https://doi.org/https://nhd.usgs.gov/wbd.html)\n- [](https://doi.org/https://developers.google.com/earth-engine/datasets/catalog/USGS_WBD_2017_HUC08)"]]
