RGBI post2000 USFS R3 Southwest multiRes Public

This is a collection of aerial digital orthophotos covering selected U.S. Forest Service and adjoining lands in the Southwest Region, encompassing Arizona and New Mexico. The data are presented in a time-enabled format, allowing the end-user to view available data year-by-year, or all available years at once, within a GIS system. The data encompass varying years from 2000 to the present, varying resolutions, and varying geographic extents, dependent upon available imagery as provided by the region. The data contains four bands, representing red, green, blue, and near-infrared wavelengths, making the data suitable for analysis using either a true-color band combination (red, green, blue) or using a false-color band combination (eg. near-infrared, red, green).

The data contains an attribute table. Notable attributes that may be of interest to an end-user are:

• lowps: the pixel size of the source raster, given in meters.

• highps: the pixel size of the top-most pyramid for the raster, given in meters.

• beginyear: the first year of data acquisition for an individual dataset.

• endyear: the final year of data acquisition for an individual dataset.

• dataset_name: the name of the individual dataset within the collection.

• metadata: A URL link to a file on IIPP's Portal containing metadata pertaining to an individual dataset within the image service.

• resolution: The pixel size of the source raster, given in meters.

A digital orthophoto is a georeferenced image prepared from aerial imagery, or other remotely-sensed data in which the displacement within the image due to sensor orientation and terrain relief has been removed. Orthophotos combine the characteristics of an image with the geometric qualities of a map. Orthoimages show ground features such as roads, buildings, and streams in their proper positions, without the distortion characteristic of unrectified aerial imagery. Digital orthoimages produced and used within the Forest Service are developed from imagery acquired through various national and regional image acquisition programs. The resulting orthoimages, also known as orthomaps, can be directly applied in remote sensing, GIS and mapping applications. They serve a variety of purposes, from interim maps to references for earth science investigations and analysis. Because of the orthographic property, an orthoimage can be used like a map for measurement of distances, angles, and areas with scale being constant everywhere. Also, they can be used as map layers in GIS or other computer-based manipulation, overlaying, and analysis. An orthoimage differs from a map in a manner of depiction of detail; on a map only selected detail is shown by conventional symbols, whereas on an orthoimage all details appear just as in original aerial or satellite imagery.