Lesson 5: Using The National Map Web Services in ArcMap - This video provides an overview and demonstrates how to use The National Map's web services in a mapping application.
What projection are the imagery services in The National Map viewer?
Imagery services in The National Map (TNM) use WGS 1984 Web Mercator (Auxiliary Sphere). The USGS ImageryOnly Service (under Base Maps) is cached (pre-generated) at this projection. Imagery services can be easily reprojected to many other popular projections for use in GIS desktop applications as background services.
Learn more: Training videos for using The National Map Products and Services
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What is the difference between tiled and dynamic services?
A tiled service contains cached tiles that render the map in small tile images. This allows the map to perform much faster when panning and zooming, compared to a dynamic service. Dynamic is considered an "older" way of displaying web maps, where each feature is called from the source data and drawn separately for every pan and zoom. Tiled base maps are cached from global scale to a scale of 1:9...
What are the URLs for imagery services in The National Map, and are they cached or dynamic?
There are several imagery services for The National Map . Some imagery services are cached and some are dynamic: USGSImageryOnly (under Base Maps), for example, is a tile cache base map service of orthoimagery. It has different imagery data sources depending on view scale. The USGSImageryOnly service uses cache tiles of 256x256 pixels in size and 96 dots per inch (dpi) resolution with 75%...
Are the scanned aerial photographic images georectified?
Scans of traditional aerial photography film products (air photos) are not georectified . The USGS does, however, offer several orthoimagery (georectified aerial photograph) products: Digital Orthophoto Quadrangle (DOQ) High Resolution Orthoimagery (HRO) National Agriculture Imagery Program (NAIP, NAIP Plus) NAIP orthoimagery has been collected for the entire conterminous United States every 3...
What do the different colors in a color-infrared aerial photograph represent?
Color-infrared (CIR) aerial photography--often called "false color" photography because it renders the scene in colors not normally seen by the human eye--is widely used for interpretation of natural resources. Atmospheric haze does not interfere with the acquisition of the image. Live vegetation is almost always associated with red tones. Very intense reds indicate dense, vigorously growing...
How often is orthoimagery in The National Map updated and what are the acquisition dates?
Orthoimagery (georectified aerial photography) available through The National Map Downloader and The National Map Services is from the USDA Farm Service Agency's National Agricultural Imagery Program (NAIP), which is 1-meter resolution. Generally, NAIP imagery is refreshed on a 3-year cycle with approximately one third of the continental U.S. flown each year. The month and year of imagery...
Related Content
- FAQ
What is the difference between tiled and dynamic services?
A tiled service contains cached tiles that render the map in small tile images. This allows the map to perform much faster when panning and zooming, compared to a dynamic service. Dynamic is considered an "older" way of displaying web maps, where each feature is called from the source data and drawn separately for every pan and zoom. Tiled base maps are cached from global scale to a scale of 1:9...
What are the URLs for imagery services in The National Map, and are they cached or dynamic?
There are several imagery services for The National Map . Some imagery services are cached and some are dynamic: USGSImageryOnly (under Base Maps), for example, is a tile cache base map service of orthoimagery. It has different imagery data sources depending on view scale. The USGSImageryOnly service uses cache tiles of 256x256 pixels in size and 96 dots per inch (dpi) resolution with 75%...
Are the scanned aerial photographic images georectified?
Scans of traditional aerial photography film products (air photos) are not georectified . The USGS does, however, offer several orthoimagery (georectified aerial photograph) products: Digital Orthophoto Quadrangle (DOQ) High Resolution Orthoimagery (HRO) National Agriculture Imagery Program (NAIP, NAIP Plus) NAIP orthoimagery has been collected for the entire conterminous United States every 3...
What do the different colors in a color-infrared aerial photograph represent?
Color-infrared (CIR) aerial photography--often called "false color" photography because it renders the scene in colors not normally seen by the human eye--is widely used for interpretation of natural resources. Atmospheric haze does not interfere with the acquisition of the image. Live vegetation is almost always associated with red tones. Very intense reds indicate dense, vigorously growing...
How often is orthoimagery in The National Map updated and what are the acquisition dates?
Orthoimagery (georectified aerial photography) available through The National Map Downloader and The National Map Services is from the USDA Farm Service Agency's National Agricultural Imagery Program (NAIP), which is 1-meter resolution. Generally, NAIP imagery is refreshed on a 3-year cycle with approximately one third of the continental U.S. flown each year. The month and year of imagery...
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