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Photogrammetry is a remote sensing technology, i.e. the technology is not in direct contact with what is being measured. From drone, aeroplane or helicopter, photographs are taken. Multiple overlapping photographs of the ground are taken. Precise measurements from the photographs can be taken to create topography maps.<\/SPAN><\/SPAN><\/P>

This data was collected using a drone carrying a digital camera in 2020<\/SPAN> and 2021.<\/SPAN><\/P>

A software package was used extract points (X,Y,Z (x & y coordinates) and z (height)) from the photographs. The data is then converted into gridded (GeoTIFF) data to create a Digital Surface Model of the earth.<\/SPAN><\/SPAN><\/P>

An ordnance datum (OD) is a vertical datum used as the basis for deriving heights on maps.<\/SPAN><\/SPAN> This data is referenced to the Malin Head Vertical Datum which is the mean sea level of the tide gauge at Malin Head, County Donegal. It was adopted as the national datum in 1970 from readings taken between 1960 and 1969 and all heights on national grid maps are measured above this datum. <\/SPAN><\/SPAN><\/P>

Digital Terrain Models (DTM) are bare earth models (no trees or buildings) of the Earth<\/SPAN><\/SPAN>\u2019<\/SPAN><\/SPAN>s surface.<\/SPAN><\/SPAN><\/P>

Digital Surface Models (DSM) are earth models in its current state. For example, a DSM includes elevations from buildings, tree canopy, electrical power lines and other features.<\/SPAN><\/SPAN><\/P>

Hillshading is a method which gives a 3D appearance to the terrain. It shows the shape of hills and mountains using shading (levels of grey) on a map, by the use of graded shadows that would be cast by high ground if light was shining from a chosen direction.<\/SPAN><\/SPAN><\/P>

This data shows the hillshade of the DSM.<\/SPAN><\/SPAN><\/P>

Th<\/SPAN>e <\/SPAN>Kilmichael Point<\/SPAN> and Dalkey Island data was collected by the Geological Survey Ireland. <\/SPAN><\/P>

Th<\/SPAN>e <\/SPAN>Bremore Head,<\/SPAN> <\/SPAN>Bunmahon<\/SPAN>,<\/SPAN> Dunbeg, Ferriters and <\/SPAN>Illauntannig <\/SPAN>data was collected by the CHERISH Project. The CHERISH project looks at coastal sites that are important to human history. These sites have important structures (for example buildings or burial sites) that may be impacted by changes to our coast. <\/SPAN><\/P>

All data formats are provided as GeoTIFF rasters. <\/SPAN><\/P>

Raster data is another name for gridded data. Raster data stores information in pixels (grid cells). Each raster grid makes up a matrix of cells (or pixels) organised into rows and columns. This data has a grid cell size of 0.25 meter by 0.25 meter. This means that each cell (pixel) represents an area of 0.25meters squared.<\/SPAN><\/P><\/DIV><\/DIV><\/DIV>", "name": "Lidar/IE_GSI_Photogrammetry_DSM_HS_GSI_25cm_IE26_ITM_MH_TIFF", "description": "

Photogrammetry is a remote sensing technology, i.e. the technology is not in direct contact with what is being measured. From drone, aeroplane or helicopter, photographs are taken. Multiple overlapping photographs of the ground are taken. Precise measurements from the photographs can be taken to create topography maps.<\/SPAN><\/SPAN><\/P>

This data was collected using a drone carrying a digital camera in 2020<\/SPAN> and 2021.<\/SPAN><\/P>

A software package was used extract points (X,Y,Z (x & y coordinates) and z (height)) from the photographs. The data is then converted into gridded (GeoTIFF) data to create a Digital Surface Model of the earth.<\/SPAN><\/SPAN><\/P>

An ordnance datum (OD) is a vertical datum used as the basis for deriving heights on maps.<\/SPAN><\/SPAN> This data is referenced to the Malin Head Vertical Datum which is the mean sea level of the tide gauge at Malin Head, County Donegal. It was adopted as the national datum in 1970 from readings taken between 1960 and 1969 and all heights on national grid maps are measured above this datum. <\/SPAN><\/SPAN><\/P>

Digital Terrain Models (DTM) are bare earth models (no trees or buildings) of the Earth<\/SPAN><\/SPAN>\u2019<\/SPAN><\/SPAN>s surface.<\/SPAN><\/SPAN><\/P>

Digital Surface Models (DSM) are earth models in its current state. For example, a DSM includes elevations from buildings, tree canopy, electrical power lines and other features.<\/SPAN><\/SPAN><\/P>

Hillshading is a method which gives a 3D appearance to the terrain. It shows the shape of hills and mountains using shading (levels of grey) on a map, by the use of graded shadows that would be cast by high ground if light was shining from a chosen direction.<\/SPAN><\/SPAN><\/P>

This data shows the hillshade of the DSM.<\/SPAN><\/SPAN><\/P>

Th<\/SPAN>e <\/SPAN>Kilmichael Point<\/SPAN> and Dalkey Island data was collected by the Geological Survey Ireland. <\/SPAN><\/P>

Th<\/SPAN>e <\/SPAN>Bremore Head,<\/SPAN> <\/SPAN>Bunmahon<\/SPAN>,<\/SPAN> Dunbeg, Ferriters and <\/SPAN>Illauntannig <\/SPAN>data was collected by the CHERISH Project. The CHERISH project looks at coastal sites that are important to human history. These sites have important structures (for example buildings or burial sites) that may be impacted by changes to our coast. <\/SPAN><\/P>

All data formats are provided as GeoTIFF rasters. <\/SPAN><\/P>

Raster data is another name for gridded data. Raster data stores information in pixels (grid cells). Each raster grid makes up a matrix of cells (or pixels) organised into rows and columns. This data has a grid cell size of 0.25 meter by 0.25 meter. This means that each cell (pixel) represents an area of 0.25meters squared.<\/SPAN><\/P><\/DIV><\/DIV><\/DIV>", "extent": { "xmin": 430961.41942312, "ymin": 596862.46298885, "xmax": 727982.16942312, "ymax": 766354.96298885, "spatialReference": { "wkid": 2157, "latestWkid": 2157 } }, "initialExtent": { "xmin": 430961.41942312, "ymin": 596862.46298885, "xmax": 727982.16942312, "ymax": 766354.96298885, "spatialReference": { "wkid": 2157, "latestWkid": 2157 } }, "fullExtent": { "xmin": 430961.41942312, "ymin": 596862.46298885, "xmax": 727982.16942312, "ymax": 766354.96298885, "spatialReference": { "wkid": 2157, "latestWkid": 2157 } }, "pixelSizeX": 0.25, "pixelSizeY": 0.25, "datasetFormat": "SDR", "uncompressedSize": 805484631510, "blockWidth": 128, "blockHeight": 128, "compressionType": "LZ77", "bandNames": [ "Band_1" ], "allowCopy": true, "allowAnalysis": true, "bandCount": 1, "pixelType": "U8", "minPixelSize": 0, "maxPixelSize": 0, "copyrightText": "Geological Survey Ireland", "serviceDataType": "esriImageServiceDataTypeGeneric", "serviceSourceType": "esriImageServiceSourceTypeDataset", "minValues": [ 0 ], "maxValues": [ 254 ], "meanValues": [ 161.1995154159848 ], "stdvValues": [ 48.77208250511391 ], "objectIdField": "", "fields": [], "capabilities": "Image,Metadata,Mensuration", "defaultMosaicMethod": "Center", "allowedMosaicMethods": "", "sortField": "", "sortValue": null, "sortAscending": true, "mosaicOperator": "First", "defaultCompressionQuality": 75, "defaultResamplingMethod": "Bilinear", "maxImageHeight": 4100, "maxImageWidth": 15000, "allowRasterFunction": true, "rasterFunctionInfos": [ { "name": "None", "description": "", "help": "" } ], "rasterTypeInfos": [ { "name": "Raster Dataset", "description": "Supports all ArcGIS Raster Datasets", "help": "" } ], "mensurationCapabilities": "Basic", "hasHistograms": true, "hasColormap": false, "hasRasterAttributeTable": true, "minScale": 0, "maxScale": 0, "exportTilesAllowed": false, "hasMultidimensions": false, "supportsStatistics": false, "supportsAdvancedQueries": false, "editFieldsInfo": null, "ownershipBasedAccessControlForRasters": null, "allowComputeTiePoints": false, "useStandardizedQueries": true, "advancedQueryCapabilities": { "useStandardizedQueries": true, "supportsStatistics": false, "supportsOrderBy": false, "supportsDistinct": false, "supportsPagination": false }, "spatialReference": { "wkid": 2157, "latestWkid": 2157 } }