2000 The Marine Conservation Society - Seasearch, Various locations in Dorset, Diver observations and detailed survey records

Seasearch records from Dorset in 2000. Seasearch is a marine habitat and species recording project for recreational SCUBA divers in the UK. The main aim of these surveys is to gather information on the marine habitats and species surrounding the UK coast, which will assist with their known extent and distribution, and ultimately contribute towards their conservation. Seasearch is co-ordinated nationally by the Marine Conservation Society. Dorset Seasearch has been active since 1995. Original survey sheets are held by Dorset Wildlife Trust, with copies held at Dorset Environmental Records Centre. Please note: All of these Seasearch records were originally input into the old Dorset database and were converted over to Marine Recorder v2 in April 2003. The old Dorset database only stored locations as Eastings and Northings values despite entries being made as Lat/Longs. The result is that all these Seasearch records have a Coordinate system of OS ref by default, even though the original paperwork recorded them as Lat/Longs. No accuracy has been lost for the OSGB36 Lat/Longs, as these allegedly translate directly. However, the surveys that used WGS84 Lat/Longs will have a small associated error, so where possible these locations have been re-entered with their original Lat/Longs. Where the Lat/Long datum has not been stated, these records have not been changed as the small error arising from the conversion is believed to be less than the error (~100m) between todays difference between OSGB36 and WGS84 Lat/Longs and the ~100m accuracy error before selective availability was turned off. Please use the Derived from field on the survey event screen to clarify how the location was recorded in the field.2000年英国多塞特（Dorset）海域Seasearch调查记录。 海查项目（Seasearch）是英国面向休闲水肺潜水爱好者的海洋生境与物种记录项目。本类调查的核心目标为收集英国周边海域的海洋生境与物种数据，以完善其已知分布范围与分布格局，并最终助力相关保护工作。该项目由英国海洋保护协会（Marine Conservation Society）统筹全国性协调工作。多塞特海查项目自1995年起持续开展。原始调查记录表由多塞特野生动物信托基金会（Dorset Wildlife Trust）保管，副本存档于多塞特环境记录中心（Dorset Environmental Records Centre）。 请注意：本批次所有海查项目记录最初均录入旧版多塞特数据库，并于2003年4月迁移至Marine Recorder v2系统。旧版多塞特数据库仅支持以东距（Eastings）与北距（Northings）格式存储位置信息，即便原始录入时采用的是经纬度（Lat/Longs）格式。因此，尽管原始纸质记录标注的是经纬度，本批次海查项目记录默认采用英国国家网格坐标（OS ref）坐标系。OSGB36（英国国家大地坐标系1936）经纬度数据的转换未损失精度，据称二者可直接映射。但采用WGS84（世界大地坐标系1984）经纬度的调查数据会存在微小转换误差，因此在可行范围内，相关位置已重新录入原始经纬度信息。对于未标注经纬度基准面的记录，因转换产生的微小误差被认为小于当前OSGB36与WGS84经纬度的差值误差（约100米），以及选择性可用性（Selective Availability）功能关闭前的约100米定位精度误差，故未对其进行修正。请通过调查事件界面的"来源"（Derived from）字段，确认野外位置的实际记录方式。