California State Waters Map Series--Offshore of Salt Point Web Services

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within California’s State Waters. The program supports a large number of coastal-zone- and ocean-management issues, including the California Marine Life Protection Act (MLPA) (California Department of Fish and Wildlife, 2008), which requires information about the distribution of ecosystems as part of the design and proposal process for the establishment of Marine Protected Areas. A focus of CSMP is to map California’s State Waters with consistent methods at a consistent scale.
The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data (the undersea equivalent of satellite remote-sensing data in terrestrial mapping), acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. It is emphasized that the more interpretive habitat and geology data rely on the integration of multiple, new high-resolution datasets and that mapping at small scales would not be possible without such data.
This approach and CSMP planning is based in part on recommendations of the Marine Mapping Planning Workshop (Kvitek and others, 2006), attended by coastal and marine managers and scientists from around the state. That workshop established geographic priorities for a coastal mapping project and identified the need for coverage of “lands” from the shore strand line (defined as Mean Higher High Water; MHHW) out to the 3-nautical-mile (5.6-km) limit of California’s State Waters. Unfortunately, surveying the zone from MHHW out to 10-m water depth is not consistently possible using ship-based surveying methods, owing to sea state (for example, waves, wind, or currents), kelp coverage, and shallow rock outcrops. Accordingly, some of the data presented in this series commonly do not cover the zone from the shore out to 10-m depth.
This data is part of a series of online U.S. Geological Survey (USGS) publications, each of which includes several map sheets, some explanatory text, and a descriptive pamphlet. Each map sheet is published as a PDF file. Geographic information system (GIS) files that contain both ESRI ArcGIS raster grids (for example, bathymetry, seafloor character) and geotiffs (for example, shaded relief) are also included for each publication. For those who do not own the full suite of ESRI GIS and mapping software, the data can be read using ESRI ArcReader, a free viewer that is available at http://www.esri.com/software/arcgis/arcreader/index.html (last accessed September 20, 2013).
The California Seafloor Mapping Program is a collaborative venture between numerous different federal and state agencies, academia, and the private sector. CSMP partners include the California Coastal Conservancy, the California Ocean Protection Council, the California Department of Fish and Wildlife, the California Geological Survey, California State University at Monterey Bay’s Seafloor Mapping Lab, Moss Landing Marine Laboratories Center for Habitat Studies, Fugro Pelagos, Pacific Gas and Electric Company, National Oceanic and Atmospheric Administration (NOAA, including National Ocean Service–Office of Coast Surveys, National Marine Sanctuaries, and National Marine Fisheries Service), U.S. Army Corps of Engineers, the Bureau of Ocean Energy Management, the National Park Service, and the U.S. Geological Survey.
These web services for the Offshore of Salt Point map area includes data layers that are associated to GIS and map sheets available from the USGS CSMP web page at https://walrus.wr.usgs.gov/mapping/csmp/index.html.
Each published CSMP map area includes a data catalog of geographic information system (GIS) files; map sheets that contain explanatory text; and an associated descriptive pamphlet. This web service represents the available data layers for this map area. Data was combined from different sonar surveys to generate a comprehensive high-resolution bathymetry and acoustic-backscatter coverage of the map area. These data reveal a range of physiographic including exposed bedrock outcrops, large fields of sand waves, as well as many human impacts on the seafloor. To validate geological and biological interpretations of the sonar data, the U.S. Geological Survey towed a camera sled over specific offshore locations, collecting both video and photographic imagery; these “ground-truth” surveying data are available from the CSMP Video and Photograph Portal at http://dx.doi.org/10.5066/F7J1015K. The “seafloor character” data layer shows classifications of the seafloor on the basis of depth, slope, rugosity (ruggedness), and backscatter intensity and which is further informed by the ground-truth-survey imagery. The “potential habitats” polygons are delineated on the basis of substrate type, geomorphology, seafloor process, or other attributes that may provide a habitat for a specific species or assemblage of organisms. Representative seismic-reflection profile data from the map area is also include and provides information on the subsurface stratigraphy and structure of the map area. The distribution and thickness of young sediment (deposited over the past about 21,000 years, during the most recent sea-level rise) is interpreted on the basis of the seismic-reflection data. The geologic polygons merge onshore geologic mapping (compiled from existing maps by the California Geological Survey) and new offshore geologic mapping that is based on integration of high-resolution bathymetry and backscatter imagery seafloor-sediment and rock samplesdigital camera and video imagery, and high-resolution seismic-reflection profiles.
The information provided by the map sheets, pamphlet, and data catalog has a broad range of applications. High-resolution bathymetry, acoustic backscatter, ground-truth-surveying imagery, and habitat mapping all contribute to habitat characterization and ecosystem-based management by providing essential data for delineation of marine protected areas and ecosystem restoration. Many of the maps provide high-resolution baselines that will be critical for monitoring environmental change associated with climate change, coastal development, or other forcings. High-resolution bathymetry is a critical component for modeling coastal flooding caused by storms and tsunamis, as well as inundation associated with longer term sea-level rise. Seismic-reflection and bathymetric data help characterize earthquake and tsunami sources, critical for natural-hazard assessments of coastal zones. Information on sediment distribution and thickness is essential to the understanding of local and regional sediment transport, as well as the development of regional sediment-management plans. In addition, siting of any new offshore infrastructure (for example, pipelines, cables, or renewable-energy facilities) will depend on high-resolution mapping. Finally, this mapping will both stimulate and enable new scientific research and also raise public awareness of, and education about, coastal environments and issues.

Web services were created using an ArcGIS service definition file. The ArcGIS REST service and OGC WMS service include all Offshore of Salt Point map area data layers. Data layers are symbolized as shown on the associated map sheets.

2007年，加州海洋保护委员会（California Ocean Protection Council）启动了加州海底测绘计划（California Seafloor Mapping Program, CSMP），旨在为加州州管海域构建一套涵盖高分辨率水深地形、海洋底栖生境与地质特征的综合海底地图。该计划可为诸多海岸带与海洋管理议题提供支撑，其中包括《加州海洋生物保护法》（California Marine Life Protection Act, MLPA）（加州鱼类与野生动物部，2008年）——该法案要求将生态系统分布信息纳入海洋保护区（Marine Protected Areas）设立的设计与提案流程。加州海底测绘计划的核心目标之一，是以统一方法与统一比例尺对加州州管海域开展测绘。

加州海底测绘计划的实施路径为：通过采集、整合、解译与可视化条带声呐数据（swath sonar data）、声学背散射（acoustic backscatter）数据、海底视频、海底摄影、高分辨率地震反射剖面（seismic-reflection profiles）以及海底沉积物采样数据，构建高精度海底地图。其地图产品可展示海底地貌形态与特征，识别潜在海洋底栖生境，并呈现表层海底地质与浅层（约100米以浅）地下地质情况。需要强调的是，更具解译价值的生境与地质数据依赖于多套全新高分辨率数据集的整合，若无此类数据，小比例尺测绘将无法实现。

该实施路径与加州海底测绘计划的规划，部分基于海洋测绘规划研讨会（Kvitek等人，2006年）的建议，参会者包括全州范围内的海岸与海洋管理者及科研人员。该研讨会确立了海岸测绘项目的地理优先级，并明确了需覆盖“岸线带（定义为平均高高潮位（Mean Higher High Water, MHHW））至加州州管海域3海里（5.6公里）界限”的海域范围。遗憾的是，受海况（如海浪、风力或海流）、海藻覆盖以及浅海岩石露头的影响，利用船载测绘方法无法始终完成从平均高高潮位至10米水深带的测绘工作。因此，本系列发布的部分数据通常未覆盖从岸线至10米水深的区域。

本数据集隶属于美国地质调查局（U.S. Geological Survey, USGS）的一系列在线出版物，每套出版物包含多幅地图图幅、若干说明性文本与一份描述性手册。每幅地图图幅均以PDF文件形式发布。每套出版物还附带地理信息系统（GIS）文件，涵盖ESRI ArcGIS栅格网格（ESRI ArcGIS raster grids，如水深地形、海底特征）与地理标签图像文件（geotiffs，如晕渲图）。对于未配备全套ESRI GIS与测绘软件的用户，可通过ESRI ArcReader读取此类数据——该免费查看器可从http://www.esri.com/software/arcgis/arcreader/index.html获取（最后访问时间：2013年9月20日）。

加州海底测绘计划是由众多联邦与州级机构、学术界及私营部门共同参与的合作项目。其合作方包括加州海岸保护委员会、加州海洋保护委员会、加州鱼类与野生动物部、加州地质调查局、加州州立大学蒙特雷湾分校海底测绘实验室、莫斯兰丁海洋实验室生境研究中心、Fugro Pelagos公司、太平洋燃气电力公司、美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA，包含国家海洋服务局-海岸测绘办公室、国家海洋保护区办公室与国家海洋渔业局）、美国陆军工程兵团、海洋能源管理局、国家公园管理局以及美国地质调查局。

针对索尔特角外海地图区域的网络服务，包含与美国地质调查局加州海底测绘计划网页（https://walrus.wr.usgs.gov/mapping/csmp/index.html）中可获取的GIS与地图图幅相关联的数据图层。

每套已发布的加州海底测绘计划地图区域均包含地理信息系统（GIS）文件数据目录、带说明性文本的地图图幅以及配套的描述性手册。本网络服务即代表该地图区域的可用数据图层。研究人员整合了不同声呐勘测数据，以生成该地图区域内覆盖范围全面的高分辨率水深地形与声学背散射数据。这些数据揭示了多样的地貌特征，包括裸露的基岩露头、大片沙波群，以及诸多人类对海底的影响活动。为验证声呐数据的地质与生物学解译结果，美国地质调查局在特定近海区域拖曳摄像雪橇，采集了视频与摄影图像；此类“地面验证（ground-truth）”勘测数据可从加州海底测绘计划视频与影像门户获取，网址为http://dx.doi.org/10.5066/F7J1015K。“海底特征”数据图层基于水深、坡度、粗糙度（rugosity）与背散射强度对海底进行分类，并通过地面验证勘测图像进一步优化分类结果。“潜在生境”多边形则基于底质类型、地貌、海底过程或其他可为特定物种或生物群落提供栖息环境的属性进行划定。本区域还提供了代表性地震反射剖面数据，可用于解析地图区域的地下地层（subsurface stratigraphy）与结构。基于地震反射数据，研究人员解译了年轻沉积物（于最近一次海平面上升期间的约21000年前沉积）的分布与厚度。地质多边形整合了陆上地质测绘数据（由加州地质调查局基于现有地图汇编而成）与基于高分辨率水深地形、背散射影像、海底沉积物与岩石样本、数码相机与视频影像以及高分辨率地震反射剖面的全新海上地质测绘结果。

地图图幅、手册与数据目录所提供的信息拥有广泛的应用场景。高分辨率水深地形、声学背散射、地面验证勘测图像与生境测绘数据，均可为海洋保护区划定与生态系统修复提供关键数据，从而支撑生境特征描述与基于生态系统的管理。诸多地图提供了高分辨率基线数据，这对于监测气候变化、海岸开发或其他驱动因素引发的环境变化至关重要。高分辨率水深地形是模拟风暴与海啸引发的海岸洪水，以及长期海平面上升导致的淹没情况的关键组成部分。地震反射与水深地形数据有助于解析地震与海啸源，这对海岸带的自然灾害评估而言至关重要。沉积物分布与厚度信息对于理解局地与区域沉积物运移，以及制定区域沉积物管理计划均不可或缺。此外，任何新型海上基础设施（如管道、电缆或可再生能源设施）的选址，都将依赖高分辨率测绘成果。最后，此类测绘工作将激发并支撑全新的科学研究，同时提升公众对海岸环境与相关议题的认知与教育水平。

本网络服务基于ArcGIS服务定义文件构建。ArcGIS REST服务与开放地理空间联盟Web地图服务（OGC WMS service）包含索尔特角外海地图区域的所有数据图层。数据图层的符号化方式与配套地图图幅一致。