A TerraAtlas presents aerial photos and overlays in a brochure format optimized for printing. It can be downloaded in a PDF format. A TerraAtlas looks like a map street atlas, but with imagery in the background. TerraAtlas is automatically produced, with a user choice of imagery and data layers, for any rectangular area or for a known geographical zone, e.g. a zipcode or a city. For downloading and self-printing, TerraAtlases are produced at 150 dpi (dots per inch). For publication, TerraAtlases are produced at 300 to 1200 dpi. The NASA Regional Applications Center has published a Washington TerraAtlas (ISBN 0-9764201-090000) and intends to publish TerraAtlases for all major US cities.
Example: Washington, DC, TerraAtlas, 48 pages
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Sample TerraAtlas pages (in PDF format, resolution reduced from 300dpi print to 150dpi for display): cover page, page 19, page 23, Index. A full 48-page atlas at resolution reduced to 150dpi is here (warning: a 72-megabyte PDF file). You can aquire a hardcopy of this artistically published atlas here or custom-make your own here. |
You can specify the area of your interest by entering (1) street address (or geographical coordinates) and optionally (2) the size of the image (width/height of the image or geographical boundaries):
TerraFly's order page presents a list of atlases available for the area of your interest as a table with the following columns:
Base Resolution, meters/pixel - Resolution of the images used to make the atlas. At 1m (one meter) resolution, 1pixel of the image represents 1 square meter of the area, similarly at 1ft (foot) resolution 1pixel=1 sq.ft = 0.3048x0.3048 sq.m. This corresponds to the scale of the atlas: the resolution of 1 meter per pixel at 150 dots per inch roughly turns into the scale of 1:6000, the resolution of 2 meters per pixel corresponds approximately to the 1:12000 scale, 4 meters/pixel - 1:24000, and so forth.
Base Data Type - Information on the imagery data source; Currently available are USGS Landsat Satellite Natural view color composite (32m resolution and aoarser), USGS Color Ortho Photo (color infra-red images), USGS BW Ortho Photo (black-and-white images), USGS Color 3ocm and 1ft Photo (color images at 1ft resolution), USGS BW 1ft Photo (black-and-white images at 1ft resolution) and USGS Topo Maps.
Size, pixels - the size in pixels of the original image used to generate your atlas. For example, the notation 2000x1000 describes a rectangular image of width 2000 pixels and height 1000 pixels. Note that if the resolution of this image is 1m, then the image covers 2x1 kilometers of the actual geographic area.
File format - Custom-made TerraAtlases are currently shipped in the PDF format, which can be viewed at and printed by Acrobat Reader, available free of charge here.
Overlay - an additional data layer over the imagery. The most popular overlay is Street Names overlay, displaying street names over the image. There are two options for street overlays: NavStreets (street network data from Navigation Technologies provides the highest quality data available in North America and Europe) and Tiger streets (produced by the United States Census; while it has accurate geometry over many areas, offsets in street name labels is noticeable in some cases).
