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Subject: Satellite Imagery FAQ - 2/5
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Summary: Satellite Imagery for Earth Observation
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Archive-name: sci/Satellite-Imagery-FAQ/part2

This document is part the Satellite Imagery FAQ

Satellite Imagery

What are the main Earth Observation Satellites and Instruments?

------------------------------

Subject: Weather Satellites

Weather Satellites

_I know nothing about these: need to find some info._

The Meteosat GOES amd GMS weather satellites operate in geostationary
orbits. That is to say, they orbit the Earth at the same speed as the
Earth's rotation, thus constantly viewing the same area. This means
that their temporal resolution is effectively unlimited, so they are
able to generate the familiar weather 'movies'.

They are, however, of limited use for (other) remote sensing purposes.
Geostationary orbits (more typical of communications satellites) are
constrained to high altitude, and to the equator. Thus good viewing
angles over high latitudes are not possible. The very large area
images are at low spatial resolution; the best achieved by Meteosat
and GOES is 2.4Km (?).

Here are a few pointers to weather pictures online, or see the
Meteorology Resources FAQ for a far longer list.

------------------------------

Subject: Earth Observation Satellites (for geosciences, etc)

Earth Observation Satellites

_See also the list below, containing pointers to detailed information
and online imagery._

Earth Observation imagery takes a number of forms, of which the most
traditional are optical and near-infrared radiation, from about 0.4
(blue) to 2.0 (IR) micrometers. Examples include Landsat, Spot and
NOAA. These generally use tracking instrunents, the basic principles
of which are briefly described in Part 2 of this FAQ _(someone point
me to a proper intro on the net - SURELY there must be one)!_.

Colour

After basic processing, imagery from these satellites may appear as
photographs. With certain visual imagery - eg SPOT - it is even
possible to display images in more-or-less their natural colour. In
practice, images for display are generally manipulated to appear
visually pleasing and to show interesting detail, and appear in _false
colour_. Visible and non-visible (IR) bands may be freely mixed in
false colour images. There are no firm rules about this, but by
convention clouds are shown as white, and vegetation red or green,
depending on the context.

Resolution

Resolution is determined primarily by instrument design, and generally
involves various compromises:
1. High spatial resolution implies imaging a small area. For an image
of 1000 pixels square, at 20m resolution the area viewed is
20x20Km, but at 1Km resolution this increases to 1000x1000Km
(actually rather more, due to the variation in viewing angle over
a large area). The latter is therefore intrinsically suited to
large-scale studies.
2. High spatial resolution also implies a high sampling frequency,
which may limit the sensitivity of the sensor.

Types of Imagery

Apart from visual and near-infrared, other bands of the spectrum
commonly used include thermal infrared (heat) and microwave (radar).
Each of these has its own applications.

3-dimensional Imagery

We see the world in three dimensions by virtue of having two eyes,
viewing the world at slightly different angles. It is possible to
emulate this and produce 3-dimensional (stereo) satellite imagery, by
superimposing images of the same ground area, viewed from different
angles (and at different times). A limited number of satellites have
this capability.

------------------------------

Subject: Synthetic Aperture Radar (SAR)

Synthetic Aperture Radar

What is SAR?

Synthetic Aperture Radar. An active microwave instrument, producing
high-resolution imagery of the Earth's surface in all weather.

There is a good introduction to imaging radar by Tony Freeman of JPL
at http://southport.jpl.nasa.gov/desc/imagingradarv3.html

_Should we have an embedded intro for the benefit of non-WWW readers?
I can ask to include the above, or try and solicit an equally expert
intro from someone here_

What are the main SAR platforms?

Several past, present and future Earth Observation Satellites. Also
the Shuttle Imaging Radar missions. See the table for a full list.
* ERS-1/ERS-2
* JERS-1
* Shuttle Imaging Radar SIR-C/X-SAR
* Almaz
* RadarSat

the future...
* ENVISAT (I'm not even making a link until I've something REAL to
put there)!
* _OK, what have I forgotten about (or never heard of)?_

What distinguishes SAR from hi-res optical imagery?

Two main properties distinguish SAR from optical imagery:
* The SAR is an active instrument. That is to say, it generates its
own illumination of the scene to be viewed, in the manner of a
camera with flash. The satellite's illumination is coherent: i.e.
all the light in any flash is exactly in phase, in the manner of a
laser, so it does not simply disperse over the distance between
the satellite and the Earth's surface. A SAR instrument can
measure both intensity and phase of the reflected light, resulting
not only in a high sensitivity to texture, but also in some
three-dimensional capabilities. Experiments with the technique of
_Interferometry_ (measuring phase differences in exactly aligned
images of the same ground area) have shown that SAR can accurately
model relief, and appears able also to detect small changes over
time.
Some consequences of being an active instrument (and using
coherent light) are:
+ Works equally day or night
+ Polarised - can be used to gain additional information (esp.
when different polarisations are available on the same
platform - as on the most recent Shuttle missions).
+ Needs a lot more power than passive sensors, and can
therefore only operate intermittently.
+ Suffers from speckle, an artifact of interference patterns in
coherent light, sensitive to texture.
* SAR is _Radar_ - i.e. it uses microwave frequency radiation.
_(note that in consequence, references to "light" above should
more strictly read "microwave radiation")._ Microwave radiation
penetrates cloud and haze, so SAR views the Earth's surface (land
and sea) in all weather. For general purpose Remote Sensing, this
is probably _the_ major advantage of SAR.
An example of its use is the ESA/Eurimage "Earthwatch" programme,
producing imagery of natural and other disasters when weather
conditions prevent other forms of surveillence. Earthwatch imagery
is available at http://gds.esrin.esa.it/CSacquisitions

What are SAR images good for ?

* Sensitive to texture: good for vegetation studies.
* Ocean waves, winds, currents.
* Seismic Activity
* Moisture content

A list of SAR applications is available at
http://southport.jpl.nasa.gov/science/SAR_REFS.html

What is the meaning of colour in a SAR image?

Of course, all SAR image colour is false colour: the notion of true
colour is meaningless in the context of invisible microwave radiation.

Most SAR images are monochrome. However, multiple images of the same
scene taken at different times may be superimposed, to generate
false-colour multitemporal images. Colour in these images signifies
changes in the scene, which may arise due to a whole host of factors,
such as moisture content or crop growth on land, or wind and wave
conditions at sea. SAR is particularly well-suited to this technique,
due to the absence of cloud cover.

The shuttle SAR's images are the nearest to 'natural' colour, in the
sense that they are viewing three different wavelengths, which can be
mapped to RGB for pseudo-naturalistic display purposes (essentially
the same as false colour in optical/IR imagery).

_Need a proper multitemporal image entry_
_________________________________________________________________

Radar Altimetry

Technique used extensively to map the oceans. There are introductions
at http://www.satobsys.co.uk/ and http://dutlru8.lr.tudelft.nl/altim/.
The latter includes the _Altimetry Atlas_, computed from GEOSAT, ERS-1
and TOPEX-Poseidon altimetry data.

An interactive browser offering sea surface height maps is available
at http://www.ccar.colorado.edu/~hendricj/topexssh.html
_________________________________________________________________

------------------------------

Subject: List of some Earth Observation Satellites

What are the main Earth Observation Satellites and Sensors

_Here is a list of some EO missions. These entries should become html
links to further information (esp. details of imagery and where to get
it if applicable) on an ad-hoc basis, as and when I have the
information to put there (contributions sought) and the time to edit
them in._

For detail on any of the following (and others), try a keyword search
on Esrin's GDS at http://gds.esrin.esa.it/.

See also http://gds.esrin.esa.it/CIDN_PROVA.source
* ADEOS Advanced Earth Observing Satellite
+ OCTS Ocean Color and Temperature Scanner
+ AVNIR Advanced Visible and Near-Infrared Radiometer
+ NSCAT NASA Scatterometer
+ TOMS Total Ozone Mapping Spectrometer
+ POLDER Polarization and Directionality of the Earth's
Reflectance
+ IMG Interferometric Monitor for Greenhouse Gasses
+ ILAS Improved Limb Atmospheric Spectrometer
+ RIS Retroflector in Space
* Almaz
+ SAR
* DMSP Defense Meterological Satellite Program
+ SSM/I (Special Sensor Microwave/Imager)
+ Visible
+ SSM/T1, SSM/T2 Microwave temperature & moisture sounders
* ERS-1 Earth Resources Satellite
+ AMI (Active Microwave Instrument), Wind mode, Wave mode, SAR
(Synthetic Aperture Radar)
+ Radar Altimeter
+ ATSR-M (Along-Track Scanning Radiometer and Microwave
Sounder)
+ PRARE (Precise Range & Range Rate Equipment)
* ERS-2 as ERS1 with addition of
+ GOME Global Ozone Monitoring Experiment
* GEOS Geodynamics Experimental Ocean Satellite
* GEOSAT GEOdetic SATellite
* GMS Geostationary Meteorological Satellites (140 E)
+ VISSR (Visible and Infra-red Spin Scan Radiometer)
* GOES Geostationary Operational Environmental Satellite (75 W and
135 W)
+ VISSR (Visible and Infra-red Spin Scan Radiometer) altimeter
* HCMM Heat Capacity Mapping Mission
+ HCMR (Heat Capacity Mapping Radiometer), visible + thermal
* INSAT Geostationary satellite of India (74 E)
* IRS Indian Remote Sensing Satellite System
+ PAN - Panchromatic Camera
+ LISS I - III (Linear Imaging Self Scanning Sensors)
+ WIFS
* JERS-1 Japanese Earth Resources Satellite
+ OPS Optical Sensors
+ SAR (Synthetic Aperture Radar)
* KOSMOS Russian EO satellite
* Landsat
+ TM (Thematic Mapper)
+ MSS (Multi-Spectral Scanner System)
+ RBV (Return Beam Vidicon) camera
* METEOR Russian meteo satellites (2-21, 3-3, 3-5)
* Meteosat (0 E, Greenwich meridian)
+ Visible/near infra-red
+ middle IR
+ Watervapour, thermal infra-red
* MOS Marine Observation Satellite
+ MESSR Multispectral Electronic Self Scanning Radiometer
+ VTIR Visible and Thermal Infrared Radiometer
+ MSR Microwave Scanning Radiometer
* Nimbus 7
+ CZCS Coastal Zone Color Scanner
+ ERB Earth Radiation Budget
+ LIMS Limb Infra-red Monitor for the Stratosphere
+ SAM-II Stratospheric Aerosol measurement (II)
+ SAMS Stratospheric and Mesospheric Sounder
+ SBUV Solar and Backscatter ultraviolet Spectrometer
+ TOMS (Total Ozone Mapping Spectrometer)
+ SMMR (Scanning Multichannel Microwave Radiometer)
+ THIR Temperature Humidity Infra-red Radiometer
* NOAA Polar Orbiting Environmental Satellites (series)
+ AVHRR Advanced Very High Resolution Radiometer
+ TOVS (TIROS Operational Vertical Sounder)
+ SBUV/2 Solar Backscatter Ultraviolet Spectrometer
* Radarsat (Canada)
+ SAR
* RESURS
+ MSU-E High resolution optical scanner
+ MSU-SK Medium-resolution Optical-IR
* SeaStar
+ SeaWiFS Sea-viewing Wide Field-of-view Sensor
* SeaSat Ocean Dynamics Satellite
+ SAR L-band
+ ALT Radar altimeter
+ SASS Radar Scatterometer
+ SMMR Scanning Multi-Spectral Microwave Radiometer
+ VIRR Visible en Infra-red Radiometer
* Shuttle
+ SIR-A Shuttle Imaging Radar
+ SIR-B
+ SIR-C (cross polarized returns VH and HV) (Apr+Oct 1994)
+ LFC Large Format Camera
+ MOMS Modular Opto-electronic Multi-spectral Scanner (2 bands)
* SkyLab
+ S 192 MSS Multispectral Scanner
+ Metric camera experiment
* SPOT
+ HRV High Resolution Visible (2x) has 2 modes:
o XS (MultiSpectral mode)
o PAN (PANchromatic mode)
* SPOT 4 (launch 1995)
+ HRVIR High Resolution Visible and Infrared
* TIROS, TOS and ITOS forerunners of the current NOAA series
(9-12+14, 13 failed just after launch). See NOAA above.
+ AVHRR Advanced Very High Resolution Radiometer
+ TOVS (TIROS Operational Vertical Sounder) consisting of:
o HIRS/2 infra-red sounder
o SSU stratospheric sounding unit
o MSU microwave sounding unit
* TOPEX/POSEIDON
+ ALT Radar Altimeter
+ TMR TOPEX Microwave Radiometer
+ LRA Laser Retroreflector Array
+ SSALT Single-Frequency Solid-State Radar Altimeter
+ DORIS Dual-Doppler Tracking System Receiver
+ GPSDR GPS Demonstration Receiver
* TRMM Tropical Rainfall Measuring Mission (launch 1997, Japan)
+ PR Precipitation Radar
+ TMI TRMM Microwave Imager
+ VIRS Visible Infrared Scanner
+ CERES Clouds and the Earth's Radiant Energy System
+ LIS Lightning Imaging Sensor

_________________________________________________________________

------------------------------

Subject: Military / Intelligence Imagery

Military / Intelligence Imagery

FAS (Federation of American Scientists) have compiled a comprehensive
guide to imaging intelligence [IMINT] at
http://www.fas.org/irp/wwwimint.html.

Didn't President Clinton recently declassify some military imagery?

By an order dated 23rd Feb 1995,
* Imagery from the CORONA, ARGON, and LANYARD missions to be
declassified within 18 months.
* Review process to be instituted for other imagery.

Details and imagery are available at
http://edcwww.cr.usgs.gov/dclass/dclass.html.
_________________________________________________________________

------------------------------

Subject: Russian Imagery

Russian Imagery

_Contributed by W. Steven Sklaris (then of DBA systems; now
[email protected]). Information regarding suppliers and availability
applies to the USA; elsewhere YMMV._

What about Russian Satellite Imagery?

The Russian Federation through the Russian Space Agency permits the
sale of commercial multi-source satellite imagery. The current
restriction placed on this imagery is limited to 2 meter resolution
but 1 meter resolutions are currently being considered. The majority
of commercial sources are from film return systems. The technical
philosophy is that the highest quality ground resolve is acquired by
film systems - no argument. The two primary commercial satellites are
KOSMOS, RESURS and Okean. The KOSMOS is utilized by the ministry of
Defense. RESURS and Okean satisfies environmental and weather
monitoring.

What are the characteristics of the KOSMOS satellite systems?

The KOSMOS has on board 2 camera systems; the KVR-1000 and TK-350. The
main attraction of the system is for mapping applications. The TK-350
is a frame camera that provides 80% overlap between images (every
third image provides 60%), along with internal and external
orientation data. This system provides for accurate determination of
latitude, longitude and elevation. The TK-350 covers an approximately
265 x 170 kilometer area per image and an 8 to 10 meter resolution.
The ground feature characteristics are provided by the KVR-1000
camera. This camera system operates simultaneously with the TK- 350
and provides 10% overlap between images. This is a panoramic camera
with 2 meter ground resolution and 36 - 44 x 165 kilometer area.

What are the characteristics of the RESURS satellite system?

The RESURS-O consists of the 01 and 02 series and are direct digital
return systems.

The RESURS-01 has on-board 2 sensor systems; the MSU-E and MSU-SK. The
MSU-E is a three channel system covering the 500 to 900 nanometer band
range. The sensor has a resolution of 45 meters and covers a 45
kilometer swath. The MSU-SK has 5 distinct channels covering the 540
to 11,800 nanometer band range. This sensor has a resolution of 160
meters for the first 4 channels and 600 meters for the 5th channel and
covers a 600 kilometer swath.

The RESURS-02 is an upgraded version of the 01 and has 4 on-board
sensor systems; the MSU-E, MSU-SK, SLR "Travers-1T" and MW-radiometer
"Delta-2." The MSU-E on this more recent satellite system covers the
same 3 channels as that of the 01 but the resolution has improved to
25 to 30 meters while retaining the 45 kilometer swath. The MSU-SK is
again included on the RESURS- 02 with no improvement from the 01
version. The Synthetic Aperture Radar "Travers-1T" and Micro Wave
radiometer "Delta-2" operate at a radiation wave length of 23cm. The
Travers-1T has a ground resolve of 200 x 200 meters and a swath width
of 100 kilometers. The Delta-2 has a ground resolve of 17,000 x 90,000
meters and a swath width of 1,000 kilometers.

The RESURS-F consists of the F1, F2 and F3 series.

The RESURS-F1 is the oldest and has on-board 2 camera types; the
KATE-200 and KFA-1000. The KATE-200 is a frame camera with a ground
resolution of 15 to 30 meters and covers a ground area of 240 x 240
kilometers. The camera system has three separate film bands covering
500 to 850 nanometers. The KFA- 1000 is an excellent higher resolution
color spectrazonal film camera and coverage of 80 x 80 kilometers. The
resolution advertised is 6 to 8 meters but is more around 8 to 10
meters. The color spectrazonal film covers the 570 to 680 nanometer
and 680 to 810 nanometer band ranges.

The RESURS-F2 is a more sophisiticated topographic camera system. The
MK-4 is a true multi-spectral camera system with data recorded on
three separate black and white film bases. There are 6 available bands
(460 to 900 nanometers) from which 3 can be selected for imaging. The
resolution of the MK-4 is about 6 to 8 meters and advertised to be
excellent for cartographic, environmental and geological surveys. The
coverage of the MK-4 is 150 x 150 kilometers. The RESURS-F2 has
on-board 2 stellar cameras to augment orientation accuracy information
but in almost all cases the cameras are not operated. Because of this
the cartographic capabilties are limited without ground control. The
excellent features of the camera are in the resolution and separate
band characteristics.

The RESURS-F3 is the most recent system and the most impressive. The
panchromatic frame camera covers 30 x 30 kilometers with at least 2
meter resolution. The 1:70,000 to 1:90,000 scale of the imagery
provides excellent ground definition.

What are the characteristics of the Okean?

The Okean-O is also a digital data return system and known to operate
for ocean monitoring. This satellite has on-board 6 sensor systems;
the MSU-V, MSU-SK, MSU-M, SLR, Scanning MW-radiometer "Delta-2", Track
MW-radiometer R- 600 and the Track VW-radiometer. The MSU-V is a eight
channel system, the spectral range is unknown. This sensor has a
resolution of 50 meters in the first 4 channels, 100 meters in the 6th
channel and 275 meters in the 7th and 8th channels and covers a 180 to
200 kilometer swath The MSU-SK has 5 distinct channels covering the
540 to 11,800 nanometer band range. This sensor has a resolution of
160 meters for the first 4 channels and 600 meters for the 5th channel
and covers a 600 kilometer swath. The MSU-M is a four channel system,
the spectral range is unknown. The sensor has a resolution of 1,600 to
2,000 meters and covers a 1,900 kilometer swath. The Side Looking
Radar operates at a radiation wavelength of 3.1cm at a ground
resolution of 800 to 1,500 meters and a swath width of 450 kilometers.
The Scanning Microwave radiometer "Delta-2" can operate at a
wavelength of 0.,8, 1.35, 2.2 or 4.5cm. The resolution is from 20,000
to 100,000 meters and covers a 800 kilometer swathwidth. The Track
Microwave radiometer R-600 operates at a wavelength of 6cm and has a
resolution of 130 meters (swath width unknown). The Track
VW-radiometer operates at a wavelength of 2.25 cm and also has a
resolution of 130 meters (swath width unknown).

What about all of the problems concerning Russian sources?

Numerous problems have been encountered with purchasing satellite
source from Russia. Most of the problems stemmed from the unauthorized
source distributors. Most distributors had access to the archives and
conducted a 1 or 2 time sale before they got caught. The Russian Space
Agency is now controling this distribution activity and has eliminated
this problem. Several other problems still exist and will not be
resolved in the near future. Access to coverage in a timely manner is
one. The archives of the KOSMOS system are not catalogued in a digital
form and acquiring coverage information is extensive and timely.
Information on coverage is typically provided in a week (depending on
the extent of coverage requested). The cloud cover information
provided with the coverage plots are very accurate but does not
satisfy all users. Several distributors of the TK-350 are preparing
digitization and browsing of the archived image files. Core Software
is considered to be the furthest along in this venture. A digital
database of the RESURS-F exists and provides extensive information
relating to coverage and collection detail. DBA Systems has a copy of
this database in their Melbourne, Florida office and can provide quick
turn-around information. The time to acquire the imagery has been
another problem area. This is much improved and is dependent on the
amount of coverage requested. A single image request, once selected
from the coverage plot, will take approximately 5 to 7 work days. Part
of this delay is due to the shipping services (DHL is 3 days from
Moscow). Film quality has also been questioned and although the
processing has significantly improved, many of the archived images are
scratched and were poorly processed during original production.

Can the film sources be provided in digital form?

Several distributors now provide the film sources in digital form.
EOSAT and DBA Systems both can perform digitization of the KVR-1000
down to the 45m range but only DBA can provide a continuous scan of
the entire TK-350 image down to the 45m spot size if desired (125m is
recommended). The precise scanning of their custom build scanner
retains the metric accuracy of the frame image. Any of the RESURS-F
films can also be scanned by the DBA scanner and JEBCO has also
provided digital product from the RESURS-F archives but we are unsure
whether the JEBCO source is still available. The color spectrazonal
film of the KFA-1000 cannot currently be captured by the DBA scanner
and other providers of color scanning of the KFA-1000 are unknown.

How can I purchase Russian Imagery?

There are several suppliers of Russian imagery and value-added
products created from the various Russian satellite systems. EOSAT,
through authorized Russian distributor Kieberso, provides digital
KVR-1000; Core Software through authorized Russian distributor
SOVINFORMSPUTNIK, provides hardcopy and digital KVR-1000 and TK-350;
DBA Systems through multiple authorized Russian distributors of
KOSMOS, RESURS and ALMAZ, provides the majority of Russian satellite
sources in both hardcopy and digital form.

Are the Russian planning any future commercial satellite systems?

Yes, the RESURS-F1M and RESURS-F2M will be upgrades to the existing
film return systems and a newer system referred to as Nika-Kuban will
be added to the RESURS satellite family. The Nika-Kuban will operate 3
camera systems and 1 forward looking digital return system to assist
in eliminating collection of cloud covered imagery. The Nika-Kuban
will offer panchromatic and multispectral collection in the 3 to 6
meter resolution range. Also planned as a major player in the
commercial remote sensing industry will be the ALMAZ-1B and ALMAZ-1C.
Both systems are currently awaiting financing to complete development
but will house the most sophisticated array of remote sensing systems
available in the commercial market. The ALMAZ-1B will offer a unique,
complex, multi-sensor payload providing for the first time, a
capability for simultaneous, multi-sensor, high resolution imagery,
including single-pass stereo coverage in the optical and multispectral
bandwidths; and high resolution, two-pass, all weather stereo in
microwave bandwidths.

Russian Imagery section by
W. Steven Sklaris
DBA Systems, Inc.
1200 South Woody Burke Rd.
Melbourne, Florida 32901
ph: 1-800-622-8554
fax: (407) 727-7019

------------------------------

Subject: Where can I get Imagery?

Where can I get Imagery?

This very frequently asked question has several parts, which are
addressed in various parts of this FAQ:
* Where can I get full products? (LIST - TBD)
* Where can I see/get samples of [some satellite's imagery] ?
* Where can I browse imagery for [some specific geographic
location]?
_Most of the references in this FAQ are global in scope - enter
lat/long or click a map.
_ * Where can I get current weather pics (online) ?
* Where can I browse images on the Web?
* Where can I get whole-world images?
* Where can I get full-resolution imagery cheap or free?
* Where can I get imagery for [my type of application]?
_That's outside the scope of this document - for the time being at
least - but check in the Further Reading_

------------------------------

Subject: How do I access the imagery catalogues?

How do I access the imagery catalogues?

There are a number of catalogue services available for interactive
login, via telnet; a few of these also offer alternative access
methods, including WWW. These will give full catalogue information,
and browse products online (typically by ftp). Some addresses for
these are listed under further reading.

CEOS IDN

The CEOS International Directory Network comprises three coordinating
nodes, together with a number of cooperating nodes. Each coordinating
node includes access to every known imagery catalogue, so in principle
you never need more than one address. These are listed in further
information.

Cintex

The Catalogue Interoperability Experiment aims to ensure
interoperability between the various catalogues.

GUIs for catalogue access

Various dedicated GUI systems exist to assist CINTEX catalogue users.
These include:
* DLR ISIS
* ESA UIT
* NASA EOSDIS V0 IMS

Details are available at http://gds.esrin.esa.it/Ccintex.cs.clients.

WWW Browse Services

In addition to the login services, there are some services available
on the WWW, offering a world-map and forms-based interface. These
include:

http://shark1.esrin.esa.it/
_Ionia_ AVHRR browser

http://tracy.esrin.esa.it:8001/
Eye-Browser Multi-Mission Browse Service: NOAA AVHRR, ERS-1
SAR, JERS OPS, Landsat TM.

http://www.coresw.com
"Imagenet" service - Landsat, SPOT and a promise of
Sovinformsputnik. Appears only to have data for America when
last checked. Commercial; the free service is limited.

http://www.eurimage.it/einet/einet_home.html
EiNet (European Imagenet) from Eurimage offers Landsat TM,
KVR-1000 and RESURS.

http://southport.jpl.nasa.gov/general.html/
SIR-C/X-SAR (Space Shuttle) imagery.

http://ic-www.arc.nasa.gov/ic/projects/bayes-group/Atlas/Earth/
Browser for Earth Observations from Shuttle

------------------------------

Subject: Where can I get full-resolution imagery cheap or free?

Where can I get full-resolution imagery cheap or free?

Answer 1: In general, you can't!
Answer 2: Old Landsat. The following was posted by Wim Bakker on
IMAGRS-L:

Paul DeVries ([email protected]) writes:

> Can anyone point me in the direction of satellite imagery of (dry) Andean
> altiplano, very cheap or in the public domain, of any vintage? Thanks.

In principle the old Landsat TM (acquired from July 16, 1982 through
September 27, 1985) and old Landsat MSS (older than 2 year) are
available at reduced prices:

MSS $ 200
TM raw $ 300
TM systematic corrected $ 425
TM precision corrected $ 600

Inquires can be made to

Customer Services
EROS Data Center (EDC)
Sioux Falls SD 57198
(605)-594-6151

In the mean time you can check on the Inventory service of EDC

URL telnet://glis.cr.usgs.gov

whether any images of your area of interest are available.

What datasets are available on CD-ROM?

Wim Bakker's report "Remote Sensing Data and GIS data on CD-ROM" is
available at http://www.itc.nl/~bakker/info/rs-data/index.html

Note - this is referenced for want of a better list, but is not kept
up-to-date.
_________________________________________________________________

------------------------------

Subject: Whole-World Images

Whole-World Images

_This answer is slanted towards Global AVHRR Land datasets. Anyone
care to talk about other images?_

Why create whole-world images?
_Because they're fun, of course! :-)_
Continental to global scale images are useful if they show
information that is studied at a large scale, such as the state
of the global biosphere. One major measure is NDVI, which
characterises 'greenness' (see RS/Vegetation FAQ for details).
Global NDVI images taken regularly over time - at intervals
between one and two weeks - enable scientists to study change
in the biosphere in detail.

How do they create whole-world images
The AVHRR Pathfinder and Global 1KM projects have created
global land datasets showing NDVI (together with lower-level
data) from AVHRR imagery, at resolutions up to 1.1KM. The
global images are created by mosaicing a large number of
individual scenes, taken over ten-day periods. Individual
scenes are first stitched to generate half-orbits (in principle
south to north pole, but generally broken because only daytime
data is used)! The half orbits are then stitched together, with
reference to a digital chart of the world.

The key to compositing for NDVI is that each point on the
Earth's surface is replicated in several images over the
sampling period. Only the _best_ NDVI value is selected, so bad
data (such as cloud cover) is discarded.

Why AVHRR? Why not, say, Landsat?
Yes, Landsat data is just as well-suited to computing NDVI as
is the AVHRR.

The NOAA satellites, in a polar orbit at an altitude of 833 KM,
orbit the Earth fourteen times per day. The AVHRR instrument
images a 2400-KM wide swath as it passes. Thus every point on
the Earth's surface is viewed at least about once per day (the
exact frequency of course varies with latitude).

The Landsat series (4-5), in near-polar orbits at 705 KM, also
orbit the Earth fourteen times per day. However, the swath
imaged is just 185KM, so a point on the equator may be viewed
only once in sixteen days. The data with which to generate
weekly, ten-day or fortnightly global composites is simply not
available. A sixteen-day composite would of course be subject
to considerable cloud-cover (see below).

Having said that, it is certainly possible to make large-area
Landsat mosaics. NASA's Landsat Pathfinder Project (see
http://pathfinder-www.sr.unh.edu/pathfinder/) has created such
datasets for the study of tropical deforestation.

How do they get rid of the cloud?
As noted above, only the best NDVI values from each input
dataset is used. Clouds will necessarily generate very low NDVI
values - _clouds are not green!_. Hence clouds are
automatically filtered out in the compositing process, provided
there is at least one cloudless view of a point within the
sample. Thus cloudlessness is not in fact guaranteed, but is
statistically far more likely than for a single pass.
Alternatively, it can be assured by collecting data over an
unlimited time period; c.f. the GeoSphere project).

Clearly this will work if and only if the characteristics being
studied are dissimilar to any cloud in at least one of the
available bands!

Further reading:

http://sun1.cr.usgs.gov/landdaac/1KM/1kmhomepage.html
Global Land 1-KM Project Front Page from USGS/EDC. Includes
extensive description of the project, and access to the data.

http://atlas.esrin.esa.it:8000/
Global AVHRR 1KM Server from ESA/ESRIN. The contents is
essentially the same as the EDC server; readers should normally
use whichever is closer to you in terms of Net connections.

http://shark1.esrin.esa.it/
_Ionia_ browser - AVHRR scenes and a browse version of a global
composite from ESA/ESRIN

http://xtreme.gsfc.nasa.gov/
AVHRR Land Pathfinder from NASA/GSFC - various global
composites.

http://infolane.com/infolane/geosphere/geospher.html
The GeoSphere project (commercial)

All the above references deal with global land datasets. NASA's
pathfinder program created also Ocean and Atmospheric datasets:

http://sst-www.jpl.nasa.gov/
SST Pathfinder from NASA/JPL

http://pegasus.nesdis.noaa.gov/pathfinder.html
Atmosphere pathfinder from NOAA

General Questions

------------------------------

Subject: Programmes and Policies

What are the National and International Remote Sensing programmes around the
World?

_(Should I have a brief summary and/or plain list here?_

This is dealt with in detail in a US Congress (Office of Technology
Assessment) report "Remotely Sensed Data: Technology, Management and
Markets", Chapter 5. Whilst this *is* explicitly a US government
document, it is generally an objective summary!

The report is available online at http://otabbs.ota.gov/T90 (thanks to
[email protected] for drawing my attention to the OTA reports).

Where can I read about government policies in Remote Sensing

_USA_: See also the previous question.
The US Congress (Office of Technology Assessment) has published some
detailed reports, two of which are available online. In addition to
the report referenced in the previous question above, "Civilian
Satellite Remote Sensing: A Strategic Approach" is available at
http://otabbs.ota.gov/T85.

_Others_: AFAIK no such government documents are available elsewhere
(but see CEOS below for worldwide policy coordination). Check the
various space agency pages, listed under URLS.

------------------------------

Subject: Where can I find information on RS and the Environment

Resources concerning the Environment

This is far too big a subject to cover in this FAQ, so here are some
links, limited to major (and established) collections:

Environmental Resources Information Network, ERIN (Australia)

The ERIN homepage is at http://kaos.erin.gov.au/erin.html
(formerly listed under misc. URLS)

Global Environmental Research Federal Metadata Network GENIE
at http://www-genie.lut.ac.uk/.

United States Geological Survey - Environment
http://www.usgs.gov/environment/index.html

United Nations Environment Programme
Frontpage is at href=http://www.unep.ch. The main RS/GIS
related information is in the Global Resource Information
Database (GRID) at sites including
http://www.grid.unep.ch/gridhome.html, http://www.grida.no/ and
http://www.inpe.br/grid/home

US Global Change Research Information Office (GCRIO)
http://www.gcrio.org/

------------------------------

Subject: Using imagery during Natural (and other) disasters.

Can satellite imagery be used to watch newsworthy events?

Earthquakes, floods, volcanos, mega-icebergs, pollution disasters...
There is imagery for all of them! Watch relevant newsgroups as news of
a disaster breaks.
That's not to say there is immediate and extensive coverage of every
possible event: the satellites capable of imaging it may not be in the
right place at the right time! However, systematic programmes exist;
notably the ESA/Eurimage Earthwatch program at
http://www.eurimage.it/Earth_Watching/Earth_Watching.html _(formerly
listed at http://gds.esrin.esa.it/CSacquisitions which is still valid)_

------------------------------

Subject: Jobs

Where can I advertise or look for a job in Remote Sensing?

_Note: there is a very high percentage of duplication between these
sources!_
* The University of Minnesota's _GIS Jobs Clearinghouse_ at
http://www.gis.umn.edu/rsgisinfo/jobs.html. A good one-stop shop,
with the best list of pointers to other sources you'll find
anywhere.
* The GIS-JOBS list at gopher://nisp.ncl.ac.uk:70/11/lists/gis-jobs
* SPIE's Employment Service, at
http://www.spie.org/web/employment/employ_home.html
* The GEOSCI-JOBS and MET-JOBS listserv. Send subscription requests
(for both lists) to [email protected]. You will recieve details
on how to post to the list, and guidelines for what is
appropriate. Either full (each job mailed separately) or digest
(weekly list) forms are available:

subscribe geosci-jobs-digest / met-jobs-digest (digest)
or subscribe geosci-jobs / met-jobs (full)
* Geographic Designs, Inc, are an agency specialising in RS/GIS.
http://www.geodesigns.com/
* GeoSearch, Inc are at http://www.geosearch.com/
* The GeoWeb Jobs Page http://www.ggrweb.com/job.html.
* SDCSC Jobs Page

In addition to the above, comp.infosystems.gis tolerates a certain
range of job postings. Please read the detailed guidelines in that
group's FAQ before posting.

_________________________________________________________________

------------------------------

Subject: Online Services Exchanges / Trade Fairs

WWW Information and Services Exchanges

The following interactive web sites are perhaps best described as
'trade fairs':
* European Wide Service Exchange http://ewse.ceo.org/
* GeoWeb http://www.ggrweb.com/

A similar but non-interactive site is
* The Geo Exchange http://giant.mindlink.net/geo_exchange

------------------------------

Subject: Geoscience Journal Information

Geoscience Journal Information

The UCSD service referenced in the August96 update of the SATFAQ drew
quite a lot of error reports, and has been withdrawn from here.

Elsevier have a mail server offering the tables of contents of their
Earth and Planetary Science journals. The subscription address for all
titles is [email protected]. For information on the service, use
subject line "help".

A good reference point on the Web is Bill Corner's site, at
http://www.man.ac.uk/Arts/geography/rs/rs_journal.html.

------------------------------

Subject: Software + hardware

Software + hardware

Here's a complete cop-out: software is rather well covered in related
documents.

Where can I find Descriptions/Reviews of Remote Sensing Software?

There is an excellect collection of reviews, now maintained by Vinton
Valentine at
http://triton.cms.udel.edu:80/~oliver/gis_gip/gis_gip_list.html. In
spite of the "gislist" name, this deals extensively with Remote
Sensing and Image Processing software. Furthermore, comments and
reviews are generally independent of the manufacturers/distributors.

Is there a list of Software Vendors?

Where can I find information on Software Packages?

These questions are covered in the comp.infosystems.gis FAQ and the
"Using the Web for Geoscience Resources" FAQ, among others.

What software is available in the Public Domain?

See the Public Domain Cartographic Software FAQ.

Pointers to the FAQs are here.

Free packages for image processing include:
* Khoros, from ftp://ftp.khoros.unm.edu/ /
http://www.khoros.unm.edu/.
There is also a commercial khoros from khoral.com (frontpage
www.khoral.com)
* Grass, from ftp://moon.cecer.army.mil/
* MultiSpec from http://dynamo.ecn.purdue.edu/~biehl/MultiSpec/

A few more listed FYI with no comment (in all but one case, simply
because I know nothing):
* http://dcz.gso.uri.edu/XBrowse/browse/browse.html XBrowse- A
client-server browse application for satellite AVHRR imagery.
* Land Analysis System, from USGS/EDC (Landsat TM & NOAA AVHRR)
* http://www.atmos.washington.edu/gcg/SV.man/SVmanual.html Satview
(University of Washington).

How can I recieve imagery on my PC?

This question is dealt with in detail in the WXSAT FAQ and other
documents at ftp://kestrel.umd.edu/pub/wxsat/docs/.

There is a nice "Build your own HRPT groundstation" webpage at
http://www.msoft.it/noaa95/.

------------------------------

Subject: Standards

Standards Committee

Committee on Earth Observations Satellites (CEOS)

_I hope reproducing this paragraph isn't violating copyright - anyone?
It comes from too many sources to attribute!_

CEOS was created in 1984 as a result of the international Economic
Summit of Industrialized Nations and serves as the focal point for
international coordination of space-related, Earth observation
activities. Policy and technical issues of common interest related to
the whole spectrum of Earth observation satellite missions and data
received from such are addressed. CEOS encourages complementarity and
compatibility among space-borne Earth observing systems through
coordination in mission planning, promotion of full and
non-discriminatory data access, setting of data product standards, and
development of compatible data products, services, and applications.
The user community benefits directly from this international
coordination.

The CEOS information system is at http://gds.esrin.esa.it/CCEOSinfo,
and contains full details and CEOS files.

See also CEOS calibration pages at
http://southport.jpl.nasa.gov/calceos/calceos.html

CEOS also sponsors

The CEOS International Directory Network (CEOS IDN)

_Need someone to wirte a real entry_ This is the authoritative
worldwide information system that answers every possible question
about Satellite Earth Observation. The complete database is held at
the three coordinating nodes in America (NASA/GSFC), Europe
(ESA/ESRIN) and Asia (NASDA/EOC). For access details, see under
Further Information.

------------------------------

Subject: Copyright

How does Copyright affect Satellite Imagery?

Wim Bakker recently supplied the following article, in part a
translation from a (Dutch) NLR article. I have taken the liberty of
cutting it down somewhat.

I understand the issue of copyright on satellite imagery may in fact
vary significantly depending on what country you're in. Mark Goodman
([email protected]) writing from a US point of view comments:

I'm not sure that satellite imagery is covered by copyright law. It
may depend on what country you're in. I believe that SPOT and EOSAT
protect their intellectual property rights through trade secrets
laws, and through restrictive sales contracts that prohibit
redistribution of raw data, even for scientific use!

Your mileage may vary!

) Copyright

There is a lot of confusion about the copyright connected to the use
of satellite images and everything related to this.

According to Websters dictionary "copyright" is
1. copy.right \-.r{i-}t\ n : the exclusive legal right to reproduce,
publish, and sell the matter and form of a literary, musical, or
artistic work - copyright aj
2. copyright vt : to secure a copyright on

In 1886, during the Convention of Bern the matter of copyright was
regulated internationally. It states that the author (creator) of a
certain matter remains the owner of his product. This also means that
if you buy a copyrighted product you pay for the _use_ of this product
and you can never claim to be the owner of such a product.
Furthermore, you can never claim any other rights about such a product
(e.g. the right to _reproduce_ the product).

In copyright the following 5 stages can be distinguished:
1. the _creation_ of a product
2. the _manufacturing_ of a product
3. the _distribution_ of a product
4. the _use_ of a product
5. the _reproduction_ of a product

These 5 points can also be distinguished with the use of satellite
images. Two operational Earth observing satellites will be described
here: Landsat and SPOT.

_Here I have cut a detailed description of Landsat and SPOT
distribution, as being (IMHO) too detailed for this FAQ - NK._

Now when does the copyright principle touch the user?
Only when the user reproduces or copies (point 5) the satellite images
is he affected by the copyright issue. At all times the user must be
aware of the owner/producer of the data. The owner/producer may or may
not permit the reproduction of the datas, but must in any case be
mentioned on all publications of satellite images!
_Note: the following details may vary in different parts of the world,
although the principles apply in any case._
For SPOT data this will be CNES; for Landsat data received by European
ground stations this will be ESA; and for Landsat data from America
this will be EOSAT (or NOAA and EROS Data Center (EDC) for old data).

The owner/producer indicates which reproductions are allowed. The
reproduction of raw data - copying CCT's and film - is _never_ allowed
and for other categories that are allowed the owner will ask for a
certain contribution for the right to reproduce the data; this is
called the _reproduction fee_.

The following reproductions are free of reproduction fee
* Posters, slides, advertisement or publications used for
conferences, meetings, symposiums and exhibitions in the field of
Remote Sensing.
* Technical reports of RS conferences, symposiums etc.
* Scientific reports and papers

For the following, a reproduction fee is due:
* Newspapers
* Magazines
* Brochures
* Books _not_ related to the field of RS
* Posters, either ones that are sold as well as free copies
* Calendars
* Atlasses
* Postcards and invitations
* Using images on TV and video

At all times the owner/producer must be mentioned on the
reproductions, even if no reproduction fee is due!
This can be done in two ways
1. To use the word _copyright_ followed by the owner/producer and the
year of production. E.g.
Copyright ESA 1988
2. To use the international sign for copyright _)_ followed by the
owner/producer and the year of production. E.g.
) CNES/NLR 1994
In the last example the NLR could have processed data from SPOT.

Conclusion

* For some (scientific) applications you owe no _reproduction fee_.
* At all times the owner/producer must be mentioned on reproductions
using the word _copyright_ or the sign _)_
* In case of doubt, ask your distributor!