Publication information Department/Agency Permanent link to this Catalogue record: publications.gc.ca/pub?id=9.843278&sl=0 This line is approximate and may change based on requirements"-Overview, p. The productive forest line is used to separate the northern and the southern parts of the country. The acquisition strategy has two main components: north, and south of the productive forest line. This strategy aims to increase high-resolution elevation data coverage for Canada and improve accessibility to the products.
#Digital terrain model government series#
It is part of the CanElevation Series created in support to the National Elevation Strategy implemented by NRCan. These product specifications apply to the High Resolution Digital Elevation Model (HRDEM) which includes Digital Terrain Model (DTM), Digital Surface Model (DSM) and other derived data. In fact, the needs for elevation data continue to grow and become more specialized, and the acquisition technologies for this type of data are not only increasing, but are also becoming more accessible and better functioning. New technologies, including LiDAR data, provide opportunities for enhancing elevation information, products and services. “Elevation data is a core theme that has been provided by Natural Resources Canada (NRCan) to Canadians as essential geographic information. Under the data sets tab, select Digital Elevation > ASTER .High Resolution Digital Elevation Model (HRDEM) : CanElevation series - product specifications.
#Digital terrain model government for free#
You can download the ASTER DEM data for free from the USGS Earth Explorer.
But you should really take a look for yourself. In October 2011, ASTER GDEM version 2 was publicly released, which was a considerable improvement.ĭespite its experimental grade, ASTER GDEM-2 is considered a more accurate representation than the SRTM elevation model in rugged mountainous terrain. Because of how passive and active sensors work, this had the most significant effect on quality of DEM.īut over time, ASTER DEM data has improved its products with artifact corrections of their own. However, the amount of cloud cover affected the accuracy of ASTER which wasn’t the case for SRTM DEM. Based on two images at different angles, it used stereo pairs and photogrammetry to measure elevation.
Despite its high-resolution and greater coverage (80% of the Earth), dissatisfied users expressed issues with its artifacts often in cloudy areas.ĪSTER GDEM used stereoscopic pairs and digital image correlation methods. As part of this project emerged the ASTER Global Digital Elevation Model (GDEM).ĪSTER GDEM boasted a global resolution of 90 meters with a resolution of 30 meters in the United States. NASA and Japan’s joint operation was the birth of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). But here’s a USGS Earth Explorer download guide to help you get started. Under the data sets tab, select Digital Elevation > SRTM > SRTM 1-ArcSecond Global . To download, select your area of interest. SRTM DEM data is being housed on the USGS Earth Explorer. Also, it covers most of the world with an absolute vertical height accuracy of less than 16m.
This 1-arc second global digital elevation model has a spatial resolution of about 30 meters. In late 2014, the United States government released the highest resolution SRTM DEM to the public. C-Band penetrated canopy cover to the ground better but SRTM still struggled in sloping regions with foreshortening, layover and shadow. Using two radar antennas and a single pass, it collected sufficient data to generate a digital elevation model using a technique known as interferometric synthetic aperture radar (inSAR). Back in February 2000, the Space Shuttle Endeavour launched with the SRTM payload. NASA only needed 11 days to capture Shuttle Radar Topography Mission (SRTM) 30-meter digital elevation model. Space Shuttle Radar Topography Mission (SRTM)
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