Description: <DIV STYLE="text-align:Left;"><DIV><DIV><P STYLE="margin:0 0 14 0;"><SPAN><SPAN>This map shows the areas where the seabed has been mapped in Irish waters. </SPAN></SPAN></P><P STYLE="margin:0 0 14 0;"><SPAN><SPAN>The seabed is mapped using boats and airplanes. The boats use special equipment called a multibeam echosounder. A multibeam echosounder is a type of sonar that is used to map the seabed. Sound waves are emitted in a fan shape beneath the boat. The amount of time it takes for the sound waves to bounce off the bottom of the sea and return to a receiver is used to determine water depth. </SPAN></SPAN></P><P STYLE="margin:0 0 14 0;"><SPAN><SPAN>LiDAR (Light Detection and Ranging) is another way to map the seabed, using airplanes. Two laser light beams are emitted from a sensor on-board an airplane. The red beam reaches the water surface and bounces back; while the green beam penetrates the water hits the seabed and bounces back. The difference in time between the two beams returning allows the water depth to be calculated. LiDAR is only suitable for shallow waters (up to 30m depth).</SPAN></SPAN></P><P STYLE="margin:0 0 14 0;"><SPAN><SPAN>The data are collected as points in XYZ format. X and Y coordinates and Z (depth). The boat travels up and down the water in a series of lines (trackline). An XYZ file is created for each line and contains thousands of points. The line files are merged together and converted into gridded data to create a Digital Terrain Model of the seabed. We use different sized boats and equipment depending on the depth of the water. This data shows the extent of each survey area. It also gives information on the boat and equipment used to map the area.</SPAN></SPAN></P><P STYLE="margin:0 0 14 0;"><SPAN><SPAN>It is a vector dataset. Vector data portray the world using points, lines, and polygons (areas).</SPAN></SPAN></P><P STYLE="margin:0 0 14 0;"><SPAN><SPAN>The survey areas are shown as polygons. Each polygon holds information on the survey id, the year of the survey, the number of the survey leg, the name of boat, the equipment used, the survey standard, other seabed information collected (sub-bottom, magnetics, gravity, water column, shipwrecks, seabed sample taken), sea area, geographical area, who carried out the survey, partner, project, amount of days it took and urls to survey reports.</SPAN></SPAN></P><P STYLE="margin:0 0 14 0;"><SPAN>This data shows areas that have been surveyed. There are plans to fill in the missing areas between 2020 and 2026. The deeper offshore waters were mapped as part of the Irish National Seabed Survey (INSS) between 1999 and 2005. INtegrated Mapping FOr the Sustainable Development of Ireland's MArine Resource (INFOMAR) is mapping the inshore areas. (2006 - 2026).</SPAN></P></DIV></DIV></DIV>
Service Item Id: 0cb776cc4fd549dcb9c323566ec15c60
Copyright Text: Contains Irish Public Sector Data (Geological Survey Ireland & Marine Institute) licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) licence