This raster dataset is a 1-degree Digital Elevation Model (DEM) showing Monterey Bay, California. These data were acquired from a DEM of Monterey Bay (monterey_w.dem), originally produced by the USGS. Original data were converted into a lattice grid to produce this layer. This layer is part of the GIS Data of the Monterey Bay collection, a compilation of data and imagery of the Monterey Bay area, including coastline, imagery, and bathymetry. This collection of data provides documented layers of of the Monterey Bay to persons/institutions of interest throughout the research and educational communities. These maps help define the geological variability of the seafloor and provide a detailed framework for future research, monitoring, and management activities. DEM's can be used as source elevation data for digital orthophotos, and, as layers in geographic information systems, for earth science analysis. DEM's can also serve as tools for volumetric analysis, for site location of towers, or for drainage basin delineation. Hatcher, G. (2008). 1-Degree Digital Elevation Model: Monterey Bay, California, 1994. Monterey Bay Aquairum Research Institute. Available at: http://purl.stanford.edu/sf815vr1246 All data are registered to the WGS84 datum with two versions of each feature, image, and grid coverage included in the collection. One is in a Geographic (decimal degrees) coordinate system and the second is in a Universal Transverse Mercator (UTM) zone 10 projection.
For strict accuracy and hard-copy production requiring feature, grid, and/or image data, the UTM projection coverages should be used. In fact, some ArcView functions will not be available unless the data are displayed in a projection. This is because a Geographic Coordinate System is NOT a projection but rather a spherical coordinate system dealing directly in latitude and longitude. However, at the scale of maps covering Monterey Bay, the errors produced by ignoring this fact are small.
NOTE: To most easily use the grid data, the ArcView Spatial Analyst extension should be installed on your system.
DEM is the terminology adopted by the USGS to describe terrain elevation data sets in a digital raster form. The standard DEM consists of a regular array of elevations cast on a designated coordinate projection system. 1-degree DEMs (3- by 3-arc second data spacing) provides coverage in 1- by 1-degree blocks. The basic elevation model is produced by or for the Defense Mapping Agency (DMA), but is distributed by the USGS in the DEM data record format.
