Subject: Satellite Imagery FAQ - 2/5
Supersedes: <sci/Satellite-Imagery-FAQ/part2_824542314@rtfm.mit.edu>
Date: 19 Mar 1996 03:58:16 GMT
References: <sci/Satellite-Imagery-FAQ/part1_827207059@rtfm.mit.edu>
Summary: Satellite Imagery for Earth Observation
X-Last-Updated: 1996/02/14


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 (?).

Click here for 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 

the future... 

   RadarSat 
   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. A
   paper describing the technique and experiments is available at 
   http://gds.esrin.esa.it/A0x0000001c.

   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 ?

this wants a better entry - else I'll just point to a bibliography on the
Net 

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

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 microvawe 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/home_page.html and 
http://dutlru8.lr.tudelft.nl/pages/atlas.html. 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 (launch 1996,
   Japan) 
      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

   See the Russian Imagery entry in this document. 
   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: 
         XS (MultiSpectral mode) 
         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: 
         HIRS/2 infra-red sounder 
         SSU stratospheric sounding unit 
         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

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
ssklaris@tds.com). 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/www/ 
   Multi-Mission Browse Service: NOAA AVHRR, ERS-1 SAR,
   JERS OPS, Landsat TM. Prototype: availability intermittent.
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://ic-www.arc.nasa.gov/ic/projects/bayes-group/Atlas/Earth/
   Browser for Earth Observations from Shuttle (but either I or they
   have a problem that needs fixing: someone tell me if it will actually
   serve you images)?


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

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 (bosse@bahnhof.se) 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/info/rs-data/index.html 



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

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://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
Mark_Goodman@achre.gov 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


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

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 majordomo@eskimo.com. 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: 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 maintained by Oliver
Weatherbee 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/ or (supposedly) 
   http://www.infc.ulst.ac.uk:80/informatics/research/vision/khoros/
   Grass, from ftp://moon.cecer.army.mil/ 

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/
. 


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

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
(Mark_Goodman@achre.gov) 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! 

