USGS High Resolution Orthoimagery for Fairfax County, VA: 18SUH075870 200902 0x1500m 4B 1
Dataset Identification:
Resource Abstract:
USGS high resolution orthorectified images from The National Map combine the image characteristics of an aerial photograph
with the geometric qualities of a map. An orthoimage is a uniform-scale image where corrections have been made for feature
displacement such as building tilt and for scale variations caused by terrain relief, sensor geometry, and camera tilt. A
mathematical equation based on ground control points, sensor calibration information, and a digital elevation model is applied
to each pixel to rectify the image to obtain the geometric qualities of a map. A digital orthoimage may be created from several
photographs mosaicked to form the final image. The source imagery may be black-and-white, natural color, color infrared, or
color near infrared (4-band) with a pixel resolution of 1-meter or finer. With orthoimagery, the resolution refers to the
distance on the ground represented by each pixel. There is no image overlap between adjacent files. Data received at EROS
were reprojected from source projection to a standard utm projection and resolution resampled to align to the U.S. National
Grid (USNG) using The National Map. The naming convention is based on the USNG, taking the coordinates of the SW corner of
the orthoimage. The metadata were imported and updated for display through The National Map at http://nationalmap.gov/viewer.html
Image-level metadata are provided in XML format. Data were compressed utilizing IAS software. The compression was JPEG2000
Lossy Compressed. The file format created was .jp2.
Citation
Title USGS High Resolution Orthoimagery for Fairfax County, VA: 18SUH075870 200902 0x1500m 4B 1
National Standards for Spatial Digital Accuracy (NSSDA)
thesaurus name >
Title American Society of Photogrammetry and Remote Sensing
revision Date
2015-07-19
Theme
Keywords
Downloadable Data
thesaurus name >
Title The National Map Type Thesaurus
revision Date
2015-07-19
Theme
Keywords
Orthoimagery
thesaurus name >
Title The National Map Theme Thesaurus
revision Date
2015-07-19
Theme
Keywords
High Resolution Orthoimagery
thesaurus name >
Title The National Map Collection Thesaurus
revision Date
2015-07-19
Theme
Keywords
1500 x 1500 meter
thesaurus name >
Title The National Map Product Extent Thesaurus
revision Date
2015-07-19
Theme
Keywords
JPEG2000
thesaurus name >
Title The National Map Product Format Thesaurus
revision Date
2015-07-19
Place
Keywords
United States
U.S.
US
thesaurus name >
Title U.S. Department of Commerce, 1995, Countries, dependencies, areas of special sovereignty, and their principal administrative
divisions, Federal Information Processing Standard 10-4,): Washington, D.C., National Institute of Standards and Technology
other Citation Details
Cinergi keyword enhanced at Tue Jan 17 07:18:26 UTC 2017
purpose:
A digital orthoimage is a geometrically accurate photographic record of landscape conditions at the time of the corresponding
aerial photography. As such, High Resolution Orthoimagery is useful for a variety of applications, such as environmental monitoring,
facility engineering/maintenance, city/county planning, property line review, etc. The digital orthoimage can be used alone
or as a raster basemap for corresponding vector line mapping. The detailed focus of High Resolution Orthoimagery provides
emergency responders critical information in determining the best evacuation routes, alternative routes and safe access to
aid. High Resolution Orthoimagery assists law enforcement personnel in determining the best locations to place surveillance
cameras in high-traffic urban areas and popular attractions. The data assists Federal, State and local emergency responders
in planning for homeland security efforts. This data also supports The National Map.