Folder: Terrain ( Show direct descendants )
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TRIM-EBM is a 2D product containing TRIM 1 features excluding toponoymy, contours and DEM for which area based features have been closed to form polygons, symbol points have been replaced with polygons and vertical integration of streams has been removed 25 Meter Resolution Not available to the public for download. Must be purchased from BC Government
ASTER is capable of collecting in-track stereo using nadir- and aft-looking near infrared cameras. Since 2001, these stereo pairs have been used to produce single-scene (60- x 60-kilomenter (km)) digital elevation models (DEM) having vertical (root-mean-squared-error) accuracies generally between 10- and 25-meters (m). The methodology used by Japan's Sensor Information Laboratory Corporation (SILC) to produce the ASTER GDEM involves automated processing of the entire ASTER Level-1A archive. Stereo-correlation is used to produce over one million individual scene-based ASTER DEMs, to which cloud masking is applied to remove cloudy pixels. All cloud-screened DEMS are stacked and residual bad values and outliers...
Orthophotos combine the image characteristics of a photograph with the geometric qualities of a map. The primary digital orthophotoquad (DOQ) is a 1-meter ground resolution, quarter-quadrangle (3.75-minutes of latitude by 3.75-minutes of longitude) image cast on the Universal Transverse Mercator Projection (UTM) on the North American Datum of 1983 (NAD83).The geographic extent of the DOQ is equivalent to a quarter-quad plus The overedge ranges a minimum of 50 meters to a maximum of 300 meters beyond the extremes of the primary and secondary corner points. The overedge is included to facilitate tonal matching for mosaicking and for the placement of the NAD83 and secondary datum corner ticks. The normal orientation...
NAIP horizontal accuracy specifications - From 2003 to 2004 the specifications were as follows: 1-meter Ground Sample Distance (GSD) imagery was to match within 3-meters, and 2-meter GSD to match within 20 meters of reference imagery. For 2005 the 1-meter GSD specification was changed to 5 meters matching to reference imagery. In 2006, all states used the same specifications as 2005 except for Utah, which required a match of +/- 6 meters to true ground. In 2007, all specifications were the same as 2006, except for Arizona, which used true ground specifications. In 2008 approximately half of the states acquired used true ground specifications and the other half used reference imagery. The 2008 states that used absolute...
Planimetric positional data represents a structuring of digitally scanned National Topographic Series mapsheet layers. Elevation data was created thorugh interpolation and extrapolation from the scanned contour layer. DATA SOURCE SIZE : 84 sheets GEO COVERAGE : Full coverage of province. Base information originates from digital scanning and vectorizing of federal 1:250,000 NTS lithographic layers of published mapsheets. DEM was created through a process of interpolation/extrapolation from original contours and the manual introduction of elevation points from hardcopy. Water and wetland closed polygonal features were created at a later date. Index Grid for NTS 1:250,000 scale maps.
The National Elevation Dataset (NED) is the primary elevation data product of the USGS. The NED is a seamless dataset with the best available raster elevation data of the conterminous United States, Alaska, Hawaii, and territorial islands. The NED is updated on a nominal two month cycle to integrate newly available, improved elevation source data. All NED data are public domain. The NED is derived from diverse source data that are processed to a common coordinate system and unit of vertical measure. NED data are distributed in geographic coordinates in units of decimal degrees, and in conformance with the North American Datum of 1983 (NAD 83). All elevation values are in meters and, over the conterminous United...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: DEM,
Digital Elevation Model,
NED,
NPLCC,
National Elevation Dataset,
Synthesis of known public LiDAR acquisitions in Region 1, compiled from multiple sources. May 2011. Needs updating.
Index Grid for NTS (National Topographic Series) 1:50,000 scale maps
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: BC,
British Columbia,
Canada,
Digital Elevation Model,
NPLCC,
The Centre for Topographic Information (CTI) jointly produces the CDED with federal, provincial and territorial government agencies as well as the private sector. A CDED consists of an ordered array of ground or reflective surface elevations, recorded in metres, at regularly spaced intervals. The source digital data for CDED is extracted from the hypsographic and hydrographic elements of the National Topographic Data Base (NTDB) at scales of 1:50 000 and 1:250 000, or the Geospatial Data Base (GDB), or various scaled positional data acquired by the provinces and territories, or remotely sensed imagery.
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