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DEM

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    Digital Elevation Model (DEM) for British Columbia produced by GeoBC. This data is the TRIM DEM converted to the Canadian Digital Elevation Data (CDED)format. The data consists of an ordered array of ground or reflective surface elevations, recorded in metres, at regularly spaced intervals. The spacing of the grid points is .75 arc seconds north/south. The data was converted into 1:50,000 grids for distribution. The scale of this modified data is 1:250,000 which was captured from the original source data which was at a scale of 1:20,000. The CDED data is available from the Federal government as well as one file for the entire province rahter than by letter blocks. See https://open.canada.ca/data/en/dataset/042f4628-94b2-40ac-9bc1-ca3ac2a27d82 to download from the Government of Canada website. The CDED format specification are available at ftp://ftp.geogratis.gc.ca/pub/nrcan_rncan/elevation/cdem_mnec/doc/CDEM_product_specs.pdf

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    This data was produced under contract for Alberta Agriculture and Forestry, Forest Management Branch in 2015-2016. Variables used were elevation, aspect, slope, landscape mesotopography (e.g. ridge, upper slope, etc). DEM was used where there was no LiDAR coverage, with a resolution of 25 m2 pixels. Canopy height was not included in this model because it was a product generated by LiDAR. In these files there is a report assessing accuracy of the models compared with field observation data; detailed accuracy data by township is available upon request.

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    This data was produced under contract for Alberta Agriculture and Forestry, Forest Management Branch in 2015-2016. Variables used were elevation, aspect, slope, landscape mesotopography (e.g. ridge, upper slope, etc). DEM was used where there was no LiDAR coverage, with a resolution of 25 m2 pixels. Canopy height was not included in this model because it was a product generated by LiDAR. In these files there is a report assessing accuracy of the models compared with field observation data; detailed accuracy data by township is available upon request.

  • This is a legacy product that is no longer supported. It may not meet current government standards. Canada3D is a digital elevation model (DEM) produced by the Canadian Forestry Service, Ontario region. The DEM consists of an ordered array of ground elevations providing coverage of the Canadian landmass. It has been derived from the cells of the Canadian Digital Elevation Data (CDED) at the 1:250 000 scale. Canada3D is available in two levels of detail: grids regularly spaced at 30 or 300 arc seconds. Canada3D 30 and 300 are recorded separately in ASCII format. The elevation values are expressed in metres with respect to mean sea level (MSL), in accordance with the North American Datum of 1983 (NAD83).

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    Landmælingar Íslands hafa unnið nýtt landhæðarlíkan af Íslandi. Um uppfærslu á eldra líkani er að ræða þar sem nýleg gögn af ólíkum uppruna þekja um 39.100 km2 eða um 38% landsins. Stærsta samfellda uppfærslan nær frá Suðurlandi til norðausturs, austur fyrir Egilsstaðir.Hæðarlíkanið hefur 10 x 10 m myndeiningar. Helsu nýleg gögn eru (sjá staðsetningu á meðfylgjandi smámynd hér fyrir neðan): 1) IPY-Lidargögn fyrir jökla landsins frá árunum 2007-2012, 15144 km2, LE90: 2,65 m. 2) Gögn úr 5-m-hæðarlínum, 10736 km2, LE90: 3,9 m. 3) Emisar radargögn, 4536 km2, LE90: 3,2 m. 4) Gögn úr 10-m-hæðarlínum, 2938 km2, LE90: 8,48 m, 5) SwedeSurvey photogrammetry gögn, 1433 km2, LE90: 2,60 m, 6) Gögn úr mælikvarða 1:25.000, 1152 km2, LE90: 3,8 m, 7) Bresk lidargögn (Dr. Susan Conway, Open University), 532 km2, LE90: 0,96-4,63 m. Líkaninu fylgir hæðarskygging, þ.e. upphleypt mynd af landinu en slíkar myndir eru gjarnan notaðar sem undirlag til að draga fram eða leggja áherslu á landslag. The National Land Survey of Iceland has made a new DTM of Iceland. The DTM is an upgrade of an earlier DTM where recent data, that vary in origin, cover 39.100 km2 or some 38% of the country. The DEM has pixel resolution of 10 x 10 m with. The main recent data are (see location on figure below): 1) IPY-lidar data for the glaciers of Iceland (surveyed in the years 2007 to 2012), 15144 km2, LE90: 2,65 m. 2) Data from 5-m-contour lines, 10736 km2, LE90: 3,9 m. 3) Emisar radar data, 4536 km2, LE90: 3,2 m. 4) Data from 10-m-contour lines, 2938 km2, LE90: 8,48 m, 5) SwedeSurvey photogrammetic data, 1433 km2, LE90: 2,60 m, 6) 1:25.000 contour data, 1152 km2, LE90: 3,8 m, 7) British lidar data (courtesy of Dr. Susan Conway, Open University), 532 km2, LE90: 0,96-4.63 m.The DTM is accompanied by a hillshade or a relief image of Iceland. Hillshade images are commonly used as a layer beneath maps or data to emphasize landscape.

  • Íslenska: Frá 2015 hefur verið opið aðgengi að hæðargögnum af Norðurheimskautinu (norður af 60°N, þar með talið af Íslandi). Gögnin hafa gengið undir nafninu ArticDEM og eru frá Polar Geospatial Center sem er staðsett í University of Minnesota (https://www.pgc.umn.edu/data/arcticdem/). Gögnin urðu til við vinnslu mikils magns af landhæðarlíkönum, flest frá 2012 en elstu gögnin eru frá 2008. Landhæðarlíkönin eru unnin úr steríópörum af gervitunglamyndum frá WorldView 1-3 og GeoEye-1. Notast var við SETSM sem er opinn hugbúnaður fyrir stafrænar myndmælingar á Bluewaters ofurtölvu University of Illinois. Hvert landhæðarlíkan hefur 2x2 m upplausn og dekkar um 18X100 km stórt svæði á jörðu. Samstarf Landmælinga Íslands, Veðurstofunnar og Polar Geospatial Center leiddi til þess að eftirfarandi aðferðir voru þróaðar til þess að vinna með gífurlegt magn gagna. Aðferðirnar eru: 1- Samræma staðsetningu allra landhæðarlíkana 2-Búa til samsett landhæðarlíkan úr öllum líkönunum með því að búa til þekju sem geymir tíma gagnanna. Hver pixill í samsetta líkaninu sem er unnið úr ArcticDEM er miðgildi allra líkana sem fyrirfinnast á svæðinu. Þar að auki: 3-Löguðum vötn >2km2 4-Bættum við lidar líkönum af jöklum úr Icelandic glaciers (Jóhanesson and others, 2013) 5-Bættum við gögnum sem safnað var með dróna úr Surtsey (Óskarsson and others, 2020) 6-Breyting úr geoíðu- í sporvöluhæði English: Since 2015, elevation data from the Arctic (north of 60°N, including Iceland) started to be openly available through the ArcticDEM project, led by the Polar Geospatial Center, University of Minnesota (https://www.pgc.umn.edu/data/arcticdem/). This data consists of a large amount of Digital Elevation Models (DEMs) repeatedly acquired (multitemporal), typically from 2012-present, and the oldest data reaching back to 2008. The DEMs are derived from satellite sub-meter stereo imagery, particularly from WorldView 1-3 and GeoEye-1. The processing of the DEMs was done using SETSM, an open-source digital photogrammetric software, in the Bluewaters supercomputer (University of Ilinois). Each DEM has 2x2m resolution and a footprint of ~18x100km. In a collaborative effort between the National Land Survey of Iceland, the Icelandic Meteorological Office and the Polar Geospatial Center, we developed methods to handle and process a large amount of data available for Iceland. The methods developed consisted of: 1-Spatial adjustment of all the available DEMs, for homogeneity and consistency in the location of each individual DEM. 2-Robust mosaicking into one single DEM of Iceland, by taking advantage of the multi-temporal coverage of DEMs. Each pixel of the mosaic corresponds to a median elevation value from the possible elevations available from the ArcticDEM. In addition, we did the following corrections of the resulting mosaic: 3-Fixing of lakes >2km2 4-Combination with lidar DEMs available for Icelandic glaciers (Jóhanesson and others, 2013) 5-Combination with a drone-based survey of Surtsey (Óskarsson and others, 2020) 6-Conversion from ellipsoidal to orthometric elevations

  • All available bathymetry and related information for Gregg Lake were collected and hard copy maps digitized where necessary. The data were validated against more recent data (Shuttle Radar Topography Mission 'SRTM' imagery and Indian Remote Sensing 'IRS' imagery) and corrected where necessary. The published data set contains the lake bathymetry formatted as an Arc ascii grid. Bathymetric contours and the boundary polygon are available as shapefiles.

  • All available bathymetry and related information for Birch Lake North Bay were collected and hard copy maps digitized where necessary. The data were validated against more recent data (Shuttle Radar Topography Mission 'SRTM' imagery and Indian Remote Sensing 'IRS' imagery) and corrected where necessary. The published data set contains the lake bathymetry formatted as an Arc ascii grid. Bathymetric contours and the boundary polygon are available as shapefiles.

  • All available bathymetry and related information for Graveyard/Cache Lakes were collected and hard copy maps digitized where necessary. The data were validated against more recent data (Shuttle Radar Topography Mission 'SRTM' imagery and Indian Remote Sensing 'IRS' imagery) and corrected where necessary. The published data set contains the lake bathymetry formatted as an Arc ascii grid. Bathymetric contours and the boundary polygon are available as shapefiles.

  • All available bathymetry and related information for Cow Lake were collected and hard copy maps digitized where necessary. The data were validated against more recent data (Shuttle Radar Topography Mission 'SRTM' imagery and Indian Remote Sensing 'IRS' imagery) and corrected where necessary. The published data set contains the lake bathymetry formatted as an Arc ascii grid. Bathymetric contours and the boundary polygon are available as shapefiles.