How much does QB imagery cost? What
is the minimum?
See the Eurimage Price
List for full details on pricing. The minimum order for a standard, natural-colour,
pan-sharpened (highest resolution) image from the archive is 25 km2,
at a cost of $17/km2, giving a total price of $425.
25 km2 of central London - from St Paul's to the middle of
Hyde Park
How does imagery from Eurimage differ from the
free satellite images I can find on the Internet?
The web images have usually been processed automatically, which often results
in poor colour and contrast and mosaicing anomalies. They are also heavily
compressed, which means a further loss of radiometric and geometric detail
and accuracy. Web images are rarely the most recent available.
Eurimage provides original data, giving you complete control of the final
result. You can make your own choice of acquisition date, or even request
an acquisition.
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Automatic contrast stretching on free imagery |
Custom stretching using original data |
Some Google Earh Imagery is from aerial photography, however (e.g. Paris), at higher resolutions than are available from any satellite.-
What do ‘resolution’ or ‘pixel size’ mean?
This refers to the area the each pixel covers on the ground. QuickBird multi-spectral
imagery has a minimum pixel size of 2.4 metres; for panchromatic and pan-sharpened
imagery the figure is 60 cm.
What do ‘multi-spectral’, ‘panchromatic’ and ‘pan-sharpened’ mean?
QuickBird multi-spectral imagery contains four spectral bands: 3 corresponding
approximately to the red, green and blue of visible light, and the fourth
band corresponding to near-infrared. These bands can be combined to give
images in either natural-colour or false-colour . Multispectral imagery
has a lower resolution (e.g. 2.4m)
Panchromatic imagery is greyscale imagery covering the same part of the spectrum
as the multi-spectral, but at ¼ the pixel size (e.g. 60cm).
Pan-sharpened imagery combines the resolution of the panchromatic with the
colour of the multi-spectral. QuickBird Pan-sharpened imagery is the highest-resolution
colour satellite imagery commercially available.
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Multi-spectral, natural colours, 2.4m |
Multi-spectral, false colours, 2.4m |
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Panchromatic, 60cm |
Pan-sharpened, natural colours, 60cm |
What can QuickBird see?
See the Gallery for large examples
of QuickBird imagery
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People (La Defense, Paris) |
Power pylons and lines, Italy |
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Count, identify and evaluate health of trees with false colour |
Aircraft and airport markings |
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Amusement park, Japan |
Shallow water, Kenya |
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Submarine and trawlers in dry dock, Iran |
Parking lot (and balloon), Japan |
Note that in certain circumstances the sensor can reveal features much smaller
than the pixel size.
QuickBird cannot identify individual people or vehicles, it cannot see in
the dark or through walls – your privacy is not threatened.
Why are some objects in my pan-sharpened image duplicated,
with the color separated?
The Panchromatic and Multispectral images are acquired almost simultaneously
but there is a delay between them of 0.2 seconds. For fast moving objects
the panchromatic and multispectral image of the object can appear in slightly
different positions – the pan-sharpened product shows both.
It is possible therefore to calculate – very roughly – the speed
of a fast moving object.
For instance a car at 100 km/h will have a shift between high-resolution
Panchromatic and Multispectral images of about 5.5 meters, or 9 pixels.
The aircraft is travelling at approx. 500 km/h
Can I request an image acquired on a precise day and
time?
No. You can ask for the image to be acquired within a certain window. But
although QuickBird can be oriented to acquire a target, and the coverage
is world-wide, the satellite is in a fixed sun-synchronous orbit, travelling
at approximately 7 km/second, and can only acquire areas as they come into
view (approximately once every 3-4 days). The sun-synchronous orbit means
that the satellite only acquires images at the same local time, approximately
10:30 AM.
If you absolutely need an acquisition on a specific date we can verify if
there is a potential satellite pass or not, but even if there is one, this
acquisition will be very expensive and you will have no Cloud Cover guarantee
(i.e. even if the acquisition is 100% cloudy you will have to pay for it!)
Can a satellite give me video imagery of a target?
Only in the movies… The QuickBird sensor scans the Earth’s surface
- rather like a scanner or fax machine - producing very large still images.
What is the file format? How can I view the imagery
I buy?
The QuickBird products are delivered in GeoTIFF format, handled by most image
processing software - such as Photoshop - or any GIS (Geographic Information
System) software. The GeoTIFF 1.0 file format fully complies with TIFF 6.0
specifications, but has the added ability to store geographic information
within file tags. Software packages - such as Photoshop - that do not read
geographic file tags will simply ignore them and open the file as a regular
TIFF. For imagery products which are not geo-referenced, these geographic
file tags are simply not specified.
Depending on the area and product you are interested in, your image processing
software may need to be able to read very large (more than 1 GB) files, with
16 bits and up to 4-layers.
What do 8-bit, 11-bit. 16-bit mean?
These numbers refer to the number of bits used to specify each colour in
an image - the more bits, the more different gradations of colour can be
expressed. QuickBird imagery is acquired with 11-bits, distributed in a
16-bit file. This 11-bit imagery can be processed to reveal information
in shadow areas, for example, which would not otherwise be visible. For
most applications, after the data has been processed to give the image
desired it is converted to 8-bits; this reduces the file size and allows
the image to be viewed in applications - such as web browsers - that cannot
handle 16-bit data.
It is possible to order QuickBird images already scaled to 8 bit.
I opened my image in Photoshop and it appears to
be completely black…
This is a consequence of an 11-bit image in a 16-bit file. Please see this Guide to
using Photoshop with QuickBird imagery.
What are the file sizes of your imagery?
This depends on several factors such as the product type, spectral options,
pixel size, and bit depth. For example, a 25 km2 3 band Standard
Image, with 60 cm pixel size and 16 bit data would be approximately 450
MB. Full scene products can be 2 GB or more just for the Panchromatic band.
Not all image processing software (or operating systems) can handle such
large files.
This
table gives approximate file sizes for various kinds of imagery.
How long will it take to download a QB image via FTP?
QuickBird images can be very large, so it is important to know the quality
of your internet connection (download speed and reliability), before ordering
electronic delivery via FTP.
For example, a QuickBird image of 1 GB (e.g. 120 Km2 of Natural
Colors Pans-harpened at 8 bit and 60 cm GSD) can be downloaded in little
more than 1 hour if you have a 2 MB/sec connection, or in more than 40 hours
if you have a 56 KB modem.
What are Basic, Standard, and Standard Ortho-ready
imagery?
Basic is the least-processed QuickBird imagery, it is provided with the QuickBird
sensor model and is intended for expert users with the resources to carry
out sophisticated processing. Basic imagery is available only as one or more
full scenes. A Basic Imagery QuickBird scene is approximately 16.5 km by
16.5 km at nadir, or 272 km2. Note that the minimum price for
a Basic scene is $16 / km2 x 272 = $4,352.
Standard Imagery is a geo-referenced product, mapped to a cartographic projection,
with a geolocation accuracy of +/- 23 m. Standard Imagery is provided with
image metadata and is intended for a wide variety of applications. It is
an area-based product, defined by your area of interest without reference
to scenes. The minimum order is 25 km2.
Standard Ortho-ready imagery is similar to Standard but can be further processed
to give a geolocation accuracy close to that available starting from Basic
Imagery.
What does “geolocation accuracy” mean?
It means the accuracy of the positional coordinates of the depicted objects
compared to other data such as maps (which themselves can be more or less
accurate).
When we say that a QuickBird Standard image has a geolocation accuracy of
23 m CE90%, we say that statistically 90% of the image has a position error
of less than 23 meters compared to the real world. This error can be larger
if the image is located in hilly/mountain areas or if it is acquired with
high off-nadir angles, as additional errors are induced.
To improve geolocation accuracy, a process called orthorectification uses
suitable image processing software and ancillary data such as DEMs (Digital
Elevation Models – 3D models of the ground) and Ground Control Points
(very accurate coordinates for specific objects). Orthorectification can
be done starting from a Basic product (better results, but more expensive
and difficult work) or a Standard Ortho-Ready product.
Depending on the requested off-nadir viewing angle and the latitude of the target, the QuickBird satellite has a certain revisit, which means the number of days after which the satellite can see the same target again. See this table showing the average values. (in allegato) Example: Paris (48.87 N, 2.33 E) with a 0-25° viewing angle has approximately a 5 days revisit, which means 6 accesses/month.
What is “off-nadir angle”?
Nadir is when the satellite is looking straight down. QuickBird can also
be rotated to see targets to either side and ahead or behind. High off-nadir
angles can mean lower quality in terms of geolocation accuracy and resolution,
while tall objects can conceal targets.
For new acquisitions the customer can define the off-nadir range preferred.
0-10° is the minimum (better quality but very long acquisition windows
due to low revisit); 0-25°, gives agood balance between quality and revisit
time.
San Francisco, 45o off-nadir - an extreme example
What is the difference between Cubic Convolution and
Nearest Neighbour resampling?
We don't reccommend NN resampling unless you need precise values for
pixel radiometry. NN resampling leaves pixel values unchanged, but produces
blocky, imprecise geometry.
Cubic Convolution vs Nearest Neighbour
The image I want is not in the archive - can I order
an acquisition?
Yes - see the Eurimage Price
List for Tasking options. Prices for Tasking start at $20 / km2 (Natural
Colours at 60 cm resolution) with a minimum of $1,800.
How can I know if there is imagery available
over my area of interest?
You can use one of the following on-line catalogues:
You can also look in GoogleEarth, as it can display DigitalGlobe coverage (the last option in the Layers menu at the bottom left of the window), but remember that this system is not fully current, so the most recent acquisitions may be missing.
How do I define my geographic area of interest?
You need to give the coordinates (latitude-longitude) of your area of interest.
You can start your searches with a very general location (e.g. Paris),
but later you will need to refine this with precise coordinates, otherwise
you risk paying for areas that you do not need.
GoogleEarth is a good tool for finding coordinates, as the bottom bar shows
the coordinates of your mouse pointer on the image.
How do I order imagery?
Please go on to our Ordering Guide [coming soon]
How long does it take to deliver my order?
For Basic and Standard Imagery, approximate processing times, after image
acquisition, are 5 business days for Priority Tasking and Image Library
orders, 10 business days for Standard Tasking, and 60 hours for Rush Tasking.
Pan-sharpened products require an additional 6 business days of processing
time. Products are usually delivered on hard media (e.g. DVD) by courier
or electronically via ftp (in this case please make sure that your internet
connection is fast and stable enough to download very large files).
Once I have my image, can I do whatever I like
with it?
Not quite. QuickBird imagery is licensed, not sold outright. There are restrictions
on how it may be used. See Eurimage
Standard Terms & Conditions and the QuickBird
Terms for details.
How much does QB imagery cost? What is the minimum?
How does imagery from Eurimage differ from the free satellite images I can find on the Internet?
What do ‘resolution’ or ‘pixel size’ mean?
What do ‘multi-spectral’, ‘panchromatic’ and ‘pan-sharpened’ mean?
Why are some objects in my pan-sharpened image duplicated, with the color separated?
Can I request an image acquired on a precise day and time?
Can a satellite give me video imagery of a target?
What is the file format? How can I view the imagery I buy?
What do 8-bit, 11-bit. 16-bit mean?
I opened my image in Photoshop and it appears to be completely black…
What are the file sizes of your imagery?
How long will it take to download a QB image via FTP?
What are Basic, Standard, and Standard Ortho-ready imagery?
What does “geolocation accuracy” mean?
What is the difference between Cubic Convolution and Nearest Neighbour resampling?
The image I want is not in the archive - can I order an acquisition?
How can I know if there is imagery available over my area of interest?
How do I define my geographic area of interest?
How long does it take to deliver my order?
Once I have my image, can I do whatever I like with it?
Catalogues: