LiDAR (Light Detection and Ranging) is a remote sensing technology, i.e. the technology is not in direct contact with what is being measured. From satellite, aeroplane or helicopter, a LiDAR system sends a light pulse to the ground. This pulse hits the ground and returns back to a sensor on the system. The time is recorded to measure how long it takes for this light to return. Knowing this time measurement scientists are able to create topography maps.LiDAR data are collected as points (X,Y,Z (x & y coordinates) and z (height)). The data is then converted into gridded (GeoTIFF) data to create a Digital Terrain Model and Digital Surface Model of the earth. This LiDAR data was collected on 25th March 2015.An ordnance datum (OD) is a vertical datum used as the basis for deriving heights on maps. 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. Digital Terrain Models (DTM) are bare earth models (no trees or buildings) of the Earth’s surface.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. 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.This data shows the hillshade of the DSM.This data was collected by New York University. All data formats are provided as GeoTIFF rasters. 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. NYU data has a grid cell size of 1meter by 1meter. This means that each cell (pixel) represents an area of 1meter squared.

Wind Speed, LV Watershed, raster, 1/2000 to 12/2015 Reference Information and Units: GCS: EPSG:4326 (http://spatialreference.org/). Projection: Data has not been projected. Pixel Size: 0.125 degrees, approx. 14km at the equator. Units: m/s-1. At surface. Data values are monthly means of daily means. File Naming Convention: WS_Year_month Data Origin: ERA Interim, Monthly Means of Daily Means, and was developed by the European Centre for Medium-Range Weather Forecasts (ECMWF). http://apps.ecmwf.int/datasets/data/interim-full-moda/levtype=sfc/ Sensor: Various, "Reanalysis (as well as analysis) is a process by which model information and observations of many different sorts are combined in an optimal way to produce a consistent, global best estimate of the various atmospheric, wave and oceanographic parameters." Code: for %A in ("C:\temp*.nc") do gdal_translate -of GTiff -ot FLOAT32 -a_srs "+init=epsg:4326" -unscale -co "COMPRESS=PACKBITS" "%A" "%A.tif Data Development/Processing: Converted TIFF data was validated against the parent NetCDF file for correct cell size and pixel value. Output TIFFs were flipped. This was remedied via batch flipping in ArcGIS (Flip tool). The GCS was batch defined in ArcGIS as SR-ORG:14. Processed data was then batch clipped to Lake Victoria and the surrounding lakes and statistics were calculated.

LiDAR (Light Detection and Ranging) is a remote sensing technology, i.e. the technology is not in direct contact with what is being measured. From satellite, aeroplane or helicopter, a LiDAR system sends a light pulse to the ground. This pulse hits the ground and returns back to a sensor on the system. The time is recorded to measure how long it takes for this light to return. Knowing this time measurement scientists are able to create topography maps.LiDAR data are collected as points (X,Y,Z (x & y coordinates) and z (height)). The data is then converted into gridded (GeoTIFF) data to create a Digital Terrain Model and Digital Surface Model of the earth. This LiDAR data was collected between June and October 2018.An ordnance datum (OD) is a vertical datum used as the basis for deriving heights on maps. 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. Digital Terrain Models (DTM) are bare earth models (no trees or buildings) of the Earth’s surface.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.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.This data shows the hillshade of the DTM.This data was collected by BlueSky and GeoAeroSpace and provided to the Geological Survey Ireland. All data formats are provided as GeoTIFF rasters but are at different resolutions. Data resolution is 1m.Both a DTM and DSM are raster data. 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 1 meter by 1 meter. This means that each cell (pixel) represents an area of 1 meter squared.

Chlorophyll (a), LV, raster, 7/2002 to 2/2021 Reference Information and Units: GCS: SR-ORG:14 (http://spatialreference.org/) Projection: Data has not been projected. Pixel Size: ~4 kilometer (km) at the equator, 0.0174532925199433 degrees Units: mg m-3 File Naming Convention: AYYYYDDDYYYYDDD, where A stands for the Aqua sensor platform, the first YYYYDDD represents the collection start year and Julian day, and the second YYYYDDD represents the collection end year and Julian day. Data Origin: Original dataset was downloaded from: http://oceandata.sci.gsfc.nasa.gov/MODIS-Aqua/Mapped/Monthly/4 km/chlor_a Sensor: MODIS Aqua Mapped worldwide monthly Modis Aqua 4km chlorophyll (a) concentration was used to develop this product. Data values are averaged over the collection period to create monthly averages Code: for %A in ("C:\temp *.nc") do gdal_translate -of GTiff -a_nodata -32767 -sds -a_ullr -180 -90 180 90 -ot FLOAT32 -co COMPRESS=PACKBITS "%A" "%A.tif Data Development/Processing: Converted TIFF data was validated against the parent NetCDF file for correct cell size and pixel value. Output TIFFs were flipped. This was remedied via batch flipping in ArcGIS (Flip tool). The GCS was batch defined in ArcGIS as SR-ORG:14. Processed data was then batch clipped to Lake Victoria and the surrounding lakes and statistics were calculated.

This collection contains 226 2023 15.24-centimeter RGB (red, green, blue) orthorectified images of an area along Lanes Creek in Caribou County, Idaho. These data were acquired July 4, 2023-July 11, 2023. These data are sourced from the Idaho Department of Fish and Game via the Idaho Lidar Consortium.These data are part of a larger collection of data products which include includes classified LAS 1.4 files, orthorectified color imagery with 0.5 foot pixel size in TIFF and SID formats, DEM surface data in TIFF format with a 1.5 foot cell size, one-foot contours, planimetric vector data, and DTM surface in DWG format, and Technical Project Report and Metadata including methodology, accuracy, and results, covering an area of approximately 25.5 square miles.For data acquisition details see the Technical Project Report.Individual image tiles can be downloaded using the Idaho Imagery Explorer.These data can be bulk downloaded from a web accessible folder.

Population density per pixel at 100 metre resolution. WorldPop provides estimates of numbers of people residing in each 100x100m grid cell for every low and middle income country. Through ingegrating cencus, survey, satellite and GIS datasets in a flexible machine-learning framework, high resolution maps of population counts and densities for 2000-2020 are produced, along with accompanying metadata. DATASET: Alpha version 2010 and 2015 estimates of numbers of people per grid square, with national totals adjusted to match UN population division estimates (http://esa.un.org/wpp/) and remaining unadjusted. REGION: Africa SPATIAL RESOLUTION: 0.000833333 decimal degrees (approx 100m at the equator) PROJECTION: Geographic, WGS84 UNITS: Estimated persons per grid square MAPPING APPROACH: Land cover based, as described in: Linard, C., Gilbert, M., Snow, R.W., Noor, A.M. and Tatem, A.J., 2012, Population distribution, settlement patterns and accessibility across Africa in 2010, PLoS ONE, 7(2): e31743. FORMAT: Geotiff (zipped using 7-zip (open access tool): www.7-zip.org) FILENAMES: Example - AGO10adjv4.tif = Angola (AGO) population count map for 2010 (10) adjusted to match UN national estimates (adj), version 4 (v4). Population maps are updated to new versions when improved census or other input data become available. Indonesia data available from WorldPop here.

This data set was created by the North Carolina Department of Agriculture and Consumer Services (NCDA&CS). This Forest (Tree) Land Cover data was derived from the North Carolina, 4 band, 2016, USDA National Agriculture Imagery Program (NAIP) imagery.It includes the entire state of NC, except Ft. Bragg. It is one (1) meter pixel resolution which makes hiding errors difficult. Some errors (incorrect classification) exists but we estimate the data is better than 90% accurate. When viewing this data, NCDA&CS highly recommends using aerials from 2016 for a base map. The original NAIP (raster) data was in TIF format (DOQQ tiles) and was natively in UTM projection.A decision rule supervised classification process was specifically designed around the tonal differences inherent in NAIP imagery. It used with spectral and textural (to separation grasslands from trees) information derived for each 4 band NAIP tile (quarter quad). A total of 3,564 tiles or 16 TBs of data were processed. The classification resulted in a 2-class classification schema. Class 1 is Forest/Trees and Class 2 Non-forest/trees. Class 2 is set to white/transparent by default. Texture processing was applied to reduce mixed pixel values between tree canopy, healthy grass and agriculture land areas. These features have similar vegetation spectral response and would otherwise result in a significant number of misclassified pixels. In many areas however, agriculture and grass land areas containing higher texture values still resulted in mixed canopy pixels. We assume this introduces around a 5% error or misclassification rate.

This is an ArcGIS Server Image Service of the 4-band 2013 National Agricultural Imagery Program (NAIP) orthorectified digital aerial photos of Montana. The web services available include: ArcGIS Server Image services, Open Geospatial Consortium, Inc. (OGC) web coverage services (WCS), and OGC web map services (WMS). The image and web coverage services provide users direct access to the native GeoTIFF files and pixel data for geoprocessing and image analysis. Imagery defaults to natural color. To view the imagery as false-color infrared (CIR), select band 4 as the red image, band 1 as the green, and band 2 as the blue. The service is available in Open GIS Consortium (OGC) formats: WCS: https://gisservicemt.gov/arcgis/rest/services/MSDI_Framework/NAIP_2013/ImageServer/WCSServer WMS: https://gisservicemt.gov/arcgis/rest/services/MSDI_Framework/NAIP_2013/ImageServer/WMSServer The data are also available from the State Library in three different formats: They are downloadable as a collection of 698 compressed natural-color MrSID images, each 24 kilometers square. These images are in Montana State Plane coordinates, units meters. The web map for accessing these images is https://montana.maps.arcgis.com/home/webmap/viewer.html?webmap=6564af20b08f4d29b61a5692ee001a2c They are downloadable as a collection of 56 compressed county mosaic (CCM) natural color MrSID images. These data are in UTM coordinates. The FTP folder containing these images is https://ftpgeoinfo.msl.mt.gov/Data/Spatial/MSDI/Imagery/2013_NAIP/UTM_County_Mosaics. They are available from the State Library as a collection 11,776 4-band (near infrared, red, green and blue) TIFF images in UTM coordinates. Each image is about 170 megabytes. The tiling format of the TIFF imagery is based on 3.75 x 3.75 minute quarter-quadrangles with a 300 pixel buffer on all four sides. An ESRI shapefile index showing the dates and times the images were acquired is available at: https://ftpgeoinfo.msl.mt.gov/Data/Spatial/MSDI/Imagery/2013_NAIP/NAIP_2013_Dates.zip. An ESRI shapefile index showing the extent of the individual TIFF image files is available at: https://ftpgeoinfo.msl.mt.gov/Data/Spatial/MSDI/Imagery/2013_NAIP/NAIP_2013_tiff_index.zip. To order TIFF images from the State Library, select the quadrangles you want from the tiff index shapefile and send them to the Library, along with a storage device of sufficient size to hold them and return postage for the device.

These data show how different types of rocks resist the flow of electrical currents across Ireland. The rock types can then be mapped. The data were collected between 2005 and 2021.Several surveys were merged to create this dataset. (1) Tellus Northern Ireland 2005-2006(2) Cavan-Monaghan, 2006(3) Tellus Border, 2011-2012(4) Tellus North Midlands, 2014-2015(5) Block A1, 2015(6) Block A2, 2016(7) Waterford, 2016(8) Block A3, 2017(9) Block A4, 2017(10) Block A5, 2018-2019(11) Block A6, 2018-2019(12) Block A7, 2019(13) Block A8 2020-2021(14) Block A9 2021The data were collected using an airplane. The airplane flies at 60 m flight height along lines that are 200 m apart. Electromagnetic data are recorded at around 6 m intervals along the flight lines. The electromagnetic system mounted on the airplane sends an electromagnetic signal (at different frequencies) into the ground and records the response of the ground returning to the system receiver. The response changes depending on the type of rock or soil that the electromagnetic signal meets. For example, graphite has a high response value (meaning it is a low resistivity rock) while limestone has a low response value (it is a high resistivity rock).The data are collected as points in XYZ format. X and Y are the airplane coordinates. Z is the different recorded data, which include electromagnetic responses and aircraft flight height. The XYZ data for each line contains thousands of points. The data from separate lines are merged to create a resistivity grid for each survey block. All the survey blocks are then merged to create a final resistivity grid for Ireland.Colours are used to show resistivity ranges. Resistivity values are defined in ohm-metre units. Pinks and reds show the highest values. Greens and blues show lower values.This is a raster dataset. Raster data stores information in a cell-based manner and consists of a matrix of cells (or pixels) arranged into rows and columns. The format of the raster is a grid. The grid cell size is 50 m by 50 m. This means that each cell (pixel) represents an area on the ground of 50 metres squared. Each cell has a colour showing the resistivity value of the rocks.The Tellus project is a national survey which collects geochemical and geophysical data across Ireland. It allows us to study the chemical and physical properties of our soil, rocks and water. It is managed by the Geological Survey Ireland.

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.This data was collected using a drone carrying a digital camera in 2020 and 2021.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.An ordnance datum (OD) is a vertical datum used as the basis for deriving heights on maps. 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. Digital Terrain Models (DTM) are bare earth models (no trees or buildings) of the Earth’s surface.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.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.This data shows the hillshade of the DSM.The Kilmichael Point and Dalkey Island data was collected by the Geological Survey Ireland. The Bremore Head, Bunmahon, Dunbeg, Ferriters and Illauntannig 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. All data formats are provided as GeoTIFF rasters. 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.

LiDAR (Light Detection and Ranging) is a remote sensing technology, i.e. the technology is not in direct contact with what is being measured. From satellite, aeroplane or helicopter, a LiDAR system sends a light pulse to the ground. This pulse hits the ground and returns back to a sensor on the system. The time is recorded to measure how long it takes for this light to return. Knowing this time measurement scientists are able to create topography maps.LiDAR data are collected as points (X,Y,Z (x & y coordinates) and z (height)). The data is then converted into gridded (GeoTIFF) data to create a Digital Terrain Model and Digital Surface Model of the earth. This LiDAR data was collected in 2007.An ordnance datum (OD) is a vertical datum used as the basis for deriving heights on maps. 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. Digital Terrain Models (DTM) are bare earth models (no trees or buildings) of the Earth’s surface.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.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.This data shows the hillshade of the DTM.This data was collected by the Office of Public Works. All data formats are provided as GeoTIFF rasters. 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. OPW data has a grid cell size of of 0.125 meter by 0.125 meter. This means that each cell (pixel) represents an area of 12.5 centimetres squared.

These data show the intensity of gamma rays released by Uranium, Thorium and Potassium in different soils and rocks in Ireland. Different soils and rock types can then be mapped. The data were collected between 2005 and 2021.Several surveys were merged to create this dataset. (1) Tellus Northern Ireland 2005-2006(2) Cavan-Monaghan, 2006(3) Tellus Border, 2011-2012(4) Tellus North Midlands, 2014-2015(5) Block A1, 2015(6) Block A2, 2016(7) Waterford, 2016(8) Block A3, 2017(9) Block A4, 2017(10) Block A5, 2018-2019(11) Block A6, 2018-2019(12) Block A7, 2019(13) Block A8 2020-2021(14) Block A9 2021The data were collected using an airplane. The airplane flies at 60 m flight height along lines that are 200 m apart. Gamma ray spectrometer data are recorded at around 60 m intervals along the flight lines. The spectrometer system mounted on the airplane records the number of gamma rays emitted per second by rocks and soils. The gamma ray intensity changes depending on the amount of Uranium, Thorium and Potassium in rocks and soil beneath the aircraft. For example, rocks such as granite contain a large amount of Uranium, Thorium and Potassium, while limestone rocks contain low amounts of these elements.The data are collected as points in XYZ format. X and Y are the airplane coordinates. Z is the different recorded data, which include gamma ray intensity and aircraft flight height. The XYZ data for each line contains thousands of points. The data from separate lines are merged to create grids of gamma ray counts and Uranium, Thorium and Potassium contents for each survey block. All the survey blocks are then merged to create final grids for Ireland.This data shows the changes in the amount of potassium, thorium and uranium contained in the ground which can then be mapped.Colours are used to show gamma ray counts, Uranium, Thorium and Potassium concentration ranges. The values are defined in counts-per-second for gamma ray counts, parts per million for Uranium and Thorium concentrations and percent for Potassium concentration. Pinks and reds show the highest values. Greens and blues show lowest values.This is a raster dataset. Raster data stores information in a cell-based manner and consists of a matrix of cells (or pixels) organized into rows and columns. The format of the raster is an image (TIFF). The image has location information (GEOTIFF). The image cell size is 50 m by 50 m. This means that each cell (pixel) represents an area on the ground of 50 metres squared. Each cell has a value which is the average value of all the points located within that cell.The Tellus project is a national survey which collects geochemical and geophysical data across Ireland. It allows us to study the chemical and physical properties of our soil, rocks and water. It is managed by the Geological Survey Ireland.

An orthoimage is remotely sensed image data in which displacement of features in the image caused by terrain relief and sensor orientation have been mathematically removed. Orthoimagery combines the image characteristics of a photograph with the geometric qualities of a map. This project consists of the creation of 3-band, 24 bit color digital orthophoto tiles for the 5-county, Pennsylvania portion DVRPC?s region utilizing a Leica ADS40 digital imaging system. The tiles were delivered in both GeoTIFF and MrSID MG3 formats. A GeoTIFF is a TIFF file which has geographic (or cartographic) data embedded as tags within the TIFF file. The geographic data can then be used to position the image in the correct location and geometry within a geographic information system (GIS) display. MrSID (Multi-resolution Seamless Image Database) is a proprietary, wavelet-based, image compression file format (*.sid) developed and patented by LizardTech, Inc. A 20:1 compression ratio was used for the MrSIDs. The complete data set contains 1,540 full ortho tiles in Pennsylvania State Plane South coordinate system, NAD83. The individual tiles measure 5,055' x 8,745' at a 1.0' pixel size. There is no image overlap between adjacent tiles.

Mosaic - An orthoimage is remotely sensed image data in which displacement of features in the image caused by terrain relief and sensor orientation have been mathematically removed. Orthoimagery combines the image characteristics of a photograph with the geometric qualities of a map. This project consists of the creation of 3-band, 24 bit color digital orthophoto tiles for the 5-county, Pennsylvania portion DVRPC?s region utilizing a Leica ADS40 digital imaging system. The tiles were delivered in both GeoTIFF and MrSID MG3 formats. A GeoTIFF is a TIFF file which has geographic (or cartographic) data embedded as tags within the TIFF file. The geographic data can then be used to position the image in the correct location and geometry within a geographic information system (GIS) display. MrSID (Multi-resolution Seamless Image Database) is a proprietary, wavelet-based, image compression file format (*.sid) developed and patented by LizardTech, Inc. A 20:1 compression ratio was used for the MrSIDs. The complete data set contains 1,540 full ortho tiles in Pennsylvania State Plane South coordinate system, NAD83. The individual tiles measure 5,055' x 8,745' at a 1.0' pixel size. There is no image overlap between adjacent tiles. Counties include: Bucks, Chester, Delaware, Montgomery, and Philadelphia

This Backscatter map shows how hard or soft the seabed is in Irish waters. The seabed in Ireland’s inshore area is between 0 and 200 metres deep. The data was collected from 1996 to 2002. Bathymetry is the measurement of how deep is the sea. Bathymetry is the study of the shape and features of the seabed. The name comes from Greek words meaning "deep" and “measure". Backscatter is the measurement of how hard is the seabed is. Bathymetry and backscatter data are collected on board boats working at sea. 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. The strength of the sound wave is used to determine how hard the bottom of the sea is. A strong sound wave indicates a hard surface (rocks, gravel), and a weak signal indicates a soft surface (silt, mud). The word backscatter comes from the fact that different bottom types “scatter” sound waves differently. The data are collected as points in XYZ format. X and Y coordinates, Z (depth) and backscatter value. 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. This is a raster dataset. Raster data stores information in a cell-based manner and consists of a matrix of cells (or pixels) organised into rows and columns. The format of the raster is an image (GeoTIFF). The image cell size is 40m by 40m. This means that each cell (pixel) represents an area on the seabed of 40 metres squared. The map is coloured using grey shades. The darker shading represents a hard seabed (e.g. rock) and lighter shading represents a soft seabed (e.g. sand, silt or mud). 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).

LiDAR (Light Detection and Ranging) is a remote sensing technology, i.e. the technology is not in direct contact with what is being measured. From satellite, aeroplane or helicopter, a LiDAR system sends a light pulse to the ground. This pulse hits the ground and returns back to a sensor on the system. The time is recorded to measure how long it takes for this light to return. Knowing this time measurement scientists are able to create topography maps.LiDAR data are collected as points (X,Y,Z (x & y coordinates) and z (height)). The data is then converted into gridded (GeoTIFF) data to create a Digital Terrain Model and Digital Surface Model of the earth. This LiDAR data was collected in November2020.An ordnance datum (OD) is a vertical datum used as the basis for deriving heights on maps. 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. Digital Terrain Models (DTM) are bare earth models (no trees or buildings) of the Earth’s surface.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.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.This data shows the hillshade of the DTM.This data was collected by the Westmeath County Council. All data formats are provided as GeoTIFF rasters. 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. The data has a grid cell size of of 0.25 meter by 0.25 meter. This means that each cell (pixel) represents an area of 25 centimetres squared.