Download pdf of WorldView-1 chapter from the Eurimage Products and Services Guide
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Offering panchromatic imagery at 50cm resolution, DigitalGlobe’s WorldView-1
is the highest resolution commercial earth-observation satellite now operating.
With unprecedented accuracy giving map ready imagery – 1:12,000 US
scale or better – right off the satellite, while exceptional agility
means acquistion of multiple targets on each pass and faster collection,
up to 750,000 km2/day. Combined with QuickBird and WorldView-2 (to be launched
in 2008) it will be part of a constellation offering very high revisit and
large area collection capacity.
QuickBird Technical Summary
WorldView-1's on-board tape recorder gives world-wide coverage.
Imagery products are offered at these levels:
Basic 1B (Level 1)
Basic Stereo Pairs (Level 1)
Standard 2A (Level 2)
Ortho-Ready Standard OR2A (Level 2)
Orthorectified (Level 3)
Panchromatic (400—900 nanometer) imagery is collected in 11-bit format (2048 gray levels) and delivered in 16 bit format for superior image interpretation (shadow detail, etc.), or 8-bit format (256 gray levels) supported by GIS and mapping applications.
Basic Imagery products are the least processed of the WorldView-1 Imagery Products. Each strip in a Basic Imagery order is processed individually; therefore, multi-strip Basic Imagery products are not mosaicked.
Basic Imagery products are radiometrically corrected and sensor corrected, but not projected to a plane using a map projection or datum. The sensor correction blends all pixels from all detectors into the synthetic array to form a single image. The resulting GSD varies over the entire product because the attitude & ephemeris slowly change during the imaging process.
Basic Imagery products are delivered at full swath width, cut into 14km lengths. Full strip width is 17.6 km at nadir; the area that this width represents on the ground depends on the collection parameters (off-nadir angle, orientation of collection, etc). Note that depending on area ordered, the length of the last piece could be less than 14 km. There will be at least 1.8 km overlap between each 14 km length delivered.
Basic Stereo Pairs are supplied as two full scenes (490 km2 ) with 90% overlap, designed for the creation of DEMs and derived GCPs.
Standard Imagery products are processed to a further extent than Basic Imagery. They are more suitable for users that require imagery in a familiar ground-based coordinate system (such as UTM Zone or State Plane).
Standard Imagery products are radiometrically corrected, sensor corrected, and projected to a plane using the map projection and datum of the customer’s choice.. All Standard Imagery products have uniform GSD throughout the entire product. If the order polygon crosses more than one strip, one product is made for each image strip that is used to fulfill the order. As the Standard Product is not mosaicked, one product will be delivered for each strip.
Standard Imagery has a coarse DEM applied to it, which is used to correct for topographic relief with respect to the reference ellipsoid. The degree of normalization is relatively small, so while this product has terrain corrections, it is not considered orthorectified.
[ top ]Ortho Ready Standard Imagery: Ortho Ready Standard Imagery has no topographic relief applied, making it suitable for custom orthorectification. Ortho Ready Standard Imagery is projected to an average elevation, either calculated from a terrain elevation model or supplied by the customer. It can be ordered from a minimum of 25 km2 from the Library, or from 64 km2 for new tasking.
[ top ]Orthorectified Imagery products are GIS-ready and are used as image base maps for a wide variety of applications that require a higher degree of absolute accuracy.
WorldView-1 Orthorectified imagery product accuracies.
Product Level |
CE90 |
RMSE |
Ortho 1:12,000 |
10.2-meters |
6.2-meters |
Custom |
Ortho Accuracy determined by the accuracy and quality of customer-supplied support data |
|
Orthorectified Imagery products are radiometrically corrected, sensor corrected, and orthorectified with a fine digital terrain model using the map projection and datum requested by the customer. For order polygons that require more than 1 strip, customers have the option to have their products mosaicked into a single product.
Orthorectified Imagery products require DEMs to remove relief displacement. Ground Control Points (GCPs) can also be used to improve the absolute accuracy. Before an order for an Orthorectified Imagery product is accepted, DigitalGlobe will determine whether it has the appropriate support data to make the desired product. The accuracy of the DEMs and/or GCPs required to make each product depends on the scale of the Orthorectified Imagery product ordered.
These products use customer-provided support data to orthorectify WorldView-1 Imagery. There is no stated accuracy associated with the Custom Orthorectified Imagery product because the quality and accuracy of the finished product is directly dependent on the quality and accuracy of the support data. DEMs and GCPs are the most typical types of support data that customers provide.
Orthorectified products have an absolute geolocation accuracy, which varies depending on mapping scale.
The delivered area for Orthorectified Products is the order polygon is black-filled to the Minimum Bounding Rectangle.
Although NGA has acquired approximately 60% of the global capacity on WorldView-1,
DigitalGlobe states that the commercially available capacity on WorldView-1
is equal to (at a minimum) that of another QuickBird
Most data collected for NGA will be available for purchase out of the archive
at the archive price
It is likely that in the future NGA will decide to move some of their orders from QB to WV-1, therefore DigitalGlobe expects that this will free more tasking capacity on QuickBird.
Cloud Cover is calculated on the intersection between the ordered area and the whole acquired strip; if over 20%, the strip is considered unusable and tasked again.
It might happen that, if the strip is produced with scene-based framing, some scenes could have cloud cover over 20% (see below). This is normal and is not a reason to reject a cloudy scene.
Acquired strip: less than 20% cloud |
Scenes produced: although the first may have more than 20% cloud cover, the scene is considered valid |
Rush tasking orders are not evaluated for cloud cover. It is the customer’s responsibility to choose dates where he is confident to get fewer clouds.
For archive orders it is the customer’s full responsibility to verify the cloud cover of the selected strips over the ordered area.
See the QuickBird section of the Product & Services Guide for details of supplied Image Support Files, ordering optionsand tasking levels.
Note that Rush Tasking is not available for WorldView-1.
WorldView-1 Imagery Products are available in the following file formats:
GeoTIFF 1.0
NITF 2.0
NITF 2.1
WorldView-1's first half-meter images can be viewed here
Guide to using Photoshop with satellite data
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Catalogues: