Review of sensors and associated imagery available

Landsat 7 etm+ Sensor

Landsat is a US satellite, which has been operating since the early 80’s. Satellites typically have a limited life span (in the region of 5 years) and the newest Landsat sensor is now the 7th in the series (Landsat 7). Landsat 7 has 7 multispectral bands (colour) at 30m x 30m pixel resolution and a panchromatic band (black and white) at 15m x 15m pixel resolution. It is possible for some applications to produce a pan merge product which effectively fuses the 30m colour data with the 15m black and white data to effectively get the best of both – a 15m colour picture/pan merge. Landsat operates in a sun-synchronous orbit and passes over the same area every 16 days (effectively the revisit frequency).

Landsat scene coverage

A full Landsat scene covers an area of 180km x 180km (see figure 1. Scene coverages). E- LISOSAT receives Landsat data from roughly 5º South of the equator. E-LISOSAT has an archive of the preceding Landsat series of sensors dating back roughly 20 years, which is extremely useful in temporal analyses of any area of interest. In order to determine the availability of Landsat imagery for your area and application (and to view a snapshot of the image). Data can effectively be supplied at 4 levels: - Path/Map orientated: This represents the lowest level of data available. For all products, satellite ephemeris data is used on the raw data received by the satellite to correct for sun angle, sensor distortions and atmospheric corrections. A path/ map orientated product has no co-ordinate system and is only north orientated. - Georectified: Effectively, Ground Control Points (GCPs) are used to register the image to a co- ordinate system. Data is georeferenced (with latitude and longitude) to any specified projection (ie Lat/long with WGS84 datum) and is typically accurate to two pixels. - Orthorectified: GCPs are used in conjunction with a 20m resolution Digital Elevation Model (DEM) to account for variations in altitude and allowing for accuracies of 1 pixel. - Pan merge: Both 15m panchromatic and 30m multispectral data are individually orthorectified and thenfused to create a 15m colour image.

For areas outside of South Africa it may be necessary to supply E-LISOSAT with 1:50 000 map sheets or Digital elevation data in order to conduct georectification and orthorectification respectively, although E-LISOSAT through its partnerships with other geo companies is often able to source these data. Any request in this regard should be forwarded to Sales and Customer Services (+27 12 334 5100).

Landsat Costs

Type Size Path/map orientated Georectified/Orthorectified Pan merge Full scene 180km x 180km R 6000 '+ R2 300 + R1000

See figure 2 for example of Landsat pan merge Landsat Applications

This table lists examples of various applications of Landsat data that have been demonstrated in the 26 year history of the Landsat program. For a more detailed description of Landsat applications with image examples, visit http://landsat.gsfc.nasa.gov/images/Landsat_Applications.html or click on the relevant hyperlinks in blue below:

1. Agriculture, Forestry and 6. Range 2. Land Use and 5. Coastal Environmental Resources Mapping 3. Geology 4. Hydrology Resources Monitoring 4.1 Determining 1.1 Discriminating 3.1 Mapping water boundaries 5.1 Determining vegetative, crop 2.1 Classifying land major geologic and surface water patterns and extent 6.1 Monitoring and timber types uses features areas of turbidity deforestation 1.2 Measuring 2.2 Cartographic 4.2 Mapping floods 6.2 Monitoring crop and timber mapping and map 3.2 Revising and flood plain 5.2 Mapping volcanic flow acreage updating geologic maps characteristics shoreline changes activity 1.3 Precision 3.3 Recognizing 4.3 Determining 5.3 Mapping shoals, 6.3 Mapping and farming land 2.3 Categorizing and classifying area extent of snow reefs and shallow monitoring water management land capabilities certain rock types and ice coverage areas pollution 1.4 Monitoring 3.4 Delineating 4.4 Measuring 5.4 Mapping and 6.4 Determining crop and forest 2.4 Monitoring unconsolidated changes and extent monitoring sea ice in effects of natural harvests urban growth rocks and soils of glacial features shipping lanes disasters 1.5 Determining range readiness, 3.5 Mapping 4.5 Measuring biomass and 2.5 Aiding regional volcanic surface turbidity and 5.5 Tracking beach 6.5 Assessing health planning deposits sediment patterns erosion and flooding drought impact 1.6 Determining 2.6 Mapping 3.6 Mapping soil conditions and transportation geologic 4.6 Delineating 5.6 Monitoring coral 6.6 Tracking oil associations networks landforms irrigated fields reef health spills 3.7 Identifying indicators of 6.7 Assessing mineral and 4.7 Monitoring lake 5.7 Determining and monitoring 1.7 Monitoring 2.7 Mapping land- petroleum inventories and coastal circulation grass and forest desert blooms water boundaries resources health patterns fires 2.8 Siting transportation and 3.8 Determining 6.8 Mapping and 1.8 Assessing power transmission regional geologic 4.8 Estimating 5.8 Measuring sea monitoring lake wildlife habitat routes structures snow melt runoff surface temperature eutrophication 2.9 Planning solid 1.9 Characterizing waste disposal 6.9 Monitoring forest range sites, power plants 3.9 Producing 4.9 Characterizing 5.9 Monitoring and mine waste vegetation and other industries geomorphic maps tropical rainfall tracking 'red' tides pollution 1.10 Monitoring 2.10 Mapping and 6.10 Monitoring and mapping managing flood 3.10 Mapping 4.10 Mapping volcanic ash insect infestations plains impact craters watersheds plumes 2.11 Tracking socio-economic 1.11 Monitoring impacts on land irrigation practices use

The SPOT 2,4 Sensors

The SPOT satellite Earth Observation System was designed by the CNES (Centre National d'Etudes Spatiales), in France, and developed with the participation of Sweden and Belgium. The system comprises a series of spacecraft plus ground facilities for satellite control and programming, image production and distribution. Thanks to the SPOT 1, SPOT 2 and SPOT 4 satellites, the system has been operational for over fifteen years. SPOT has several advantages over Landsat in that it offers 4 multispectral bands at 20m resolution and one panchromatic band at 10m resolution. It has the capacity to acquire stereo pairs (for DEM generation) and is able to revisit the same area every 5 days (effectively the revisit period). This is because Spot can tilt E-W as it orbits.

SPOT scene Coverage

A full SPOT scene covers an area of 60km x 60km and in order to service its clients needs, E- LISOSAT also offers a smaller data chunk at 30km x 30km (see figure 1. for spot coverages). E- LISOSAT also receives SPOT data from roughly 5º South of the equator. In order to determine the availability of SPOT imagery for your area and application (and to view a snapshot of the image). Spot data is also supplied at the 4 levels described for Landsat.

SPOT Costs

Resolutio Path/map Georectifie Orthorectifie Type Size n orientated d d Full scene colour 60kmx60km 20m R 12 000 R 14 760 R 14 760 Full scene Black & white 60kmx60km 10m R 12 000 R 14 760 R 14 760 Full scene pan merge 60kmx60km 10m R 18 000 Quarter scene colour 30kmx30km 20m R 6 000 R 8 760 R 8 760 Quarter scene Black & white 30kmx30km 10m R 6 000 R 8 760 R 8 760 Quarter scene pan merge 30kmx30km 10m R 9 000

*Note that scenes ordered between 1986 and 1998 are discounted by 50%

Applications

For a full list of applications for SPOT imagery, visist http://www.spot.com/home/appli/welcome.htm or click on the hyperlink application which is of interest to you below:

> AGRICULTURE > PLANNING, LAND USE AND LANDCOVER > CADASTRAL MAPPING > CARTOGRAPHY AND TOPOGRAPHY > URBAN PLANNING > FORESTRY > NATURAL RESERVE MANAGEMENT AND PLANNING > NATURAL HAZARD AND POLLUTION MONITORING > GEOLOGY, MINERAL AND OIL EXPLORATION > WATER RESOURCES > COASTAL AND OCEAN STUDIES

> MONITORING AND SURVEILLANCE

See figure 3 for an example of Spot imagery Spot 5 Sensor

On 3 May 2002 Spot 5 was successfully launched on an Ariane 4 rocket from the Guiana Space Centre, Europe’s spaceport in Kourou, French Guiana, and is now fully operational.

SPOT 5 offers unrivalled acquisition capability with its two HRG (High Resolution Geometric) instruments, each covering a wide imaging swath of 60 km x 60 km at a resolution of 2.5 metres, and its HRS (High Resolution Stereoscopic) instrument, which supports operational production of high- accuracy digital elevation models (DEMs).

Spot 5 is ultimately able to provide multispectral imagery at 10m resolution and panchromatic imagery at 5m resolution. By combining the two HRG instruments it is also possible to provide supersampled panchromatic imagery at 2.5m resolution with the normal 60km x 60km scene size.

SPOT 5 Costs

Archived Products 60kmx60km 40kmx40km 30kmx30km 20kmx20km 20m colour/10m B&W € 1 900 10m colour/5m B&W € 2 700 € 2 025 € 1 350 € 1 020 2.5mB&W € 5 400 € 4 050 € 2 700 € 2 040

Programmed Products 60kmx60km 40kmx40km 30kmx30km 20kmx20km 20m colour/10m B&W € 2 700 10m colour/5m B&W € 3 500 € 2 825 € 2 150 € 1 820 2.5mB&W € 6 200 € 4 850 € 3 500 € 2 840

*Note priority programming is avaliable at + € 3100

DEM Products avaliable on request

Applications

http://www.spotimage.fr/spot5/appli/eng/appli_frame.html

Examples for spot 5 for an area in Tolouse in France are given below

Spot 5 10m colour Spot 5 5m pan Spot 5 2.5m supersampled pan

3d spot 5 colour merge

Spot 2.5m colour merge for Eskom Head Office Johannesburg Spot 5 High Resolution Stereoscopic Imagery

This document is aimed at detailing the basic principles of Spot Image’s offer regarding HRS and Reference3D products.

What is HRS ?

HRS stands for High Resolution Stereoscopy. Carried by SPOT 5, HRS is a stereoscopic sensor, capturing simultaneous stereopairs (simultaneity is the key to build the most efficient and cheapest DTM production line). A single HRS stereo strip images up to 600 km x 120 km (72.000 sq. km) in Panchromatic. The revisit capability is 26 days. HRS is due to acquire at least 30 Millions sq. km of validated cloudless imagery within 5 years.

The HRS images are received by Spot image, who has got exclusive distribution and adaptation rights over HRS data.

What is Reference3D ?

Reference3D is a database. Reference3D does not include HRS stereopairs, but is built mainly from HRS data :

As soon as received from the satellite, each and every HRS stereo strip is validated to identify the areas where the data is suitable for DTM production. Invalidated areas (clouds, haze, smoke, snow,…) are reported to the HRS tasking team, to be tasked again and again. After several attempts, the decision is made to use adequate ―external‖ data to fill the remaining gaps : eg stereopairs from the Spot archive or from ASTER, SRTM DTM, ERS tandem ,…. It is expected, as an average, that HRS will form at least 90% of the input data of Reference3D.

After a significant area is covered, the whole data set is processed to extract DTM and orthorectified image, which are integrated into Reference3D, along with detailed quality information.

Reference3D is a 3-layer database, stored into 1° by 1° tiles, under DIMAP format : a DTM layer , DTED 2 class : 1 arc sec. posting, an HRS orthoimage layer, rectified upon the above DTM : 1/3 arc sec. posting, a specific layer including node-by-node parameters among which : estimated values of the local accuracy, for the DTM and for the orthoimage the data provenance (HRS, SRTM, ASTER,…) of the DTM and of the orthoimage recording of the processes which were applied (interpolation, smoothing, corrections…)

The first step of the calibration phase, closed on July 12th, shows that the vertical accuracy of HRS DEMs is better than 10m @ 90%, the horizontal accuracy (without GCPs) of both HRS DEM and Orthoimage being 35m, in line with CNES (French Space Agency) expectations. The second step of the calibration phase, dedicated to the fine tuning of geometrical model and system parameters, will end on December 6th 2002. Target value for horizontal accuracy without GCP is 15 m @ 90%, and will be reached only at that time, after precise assessment of in-flight parameters, and using sophisticated processing tools. .

Reference3D products

Important : prior to any proposal, a feasibility study is necessary. The main goal is to agree upon the specifications (technical dialogue with the user), to study whether the acquisition is possible regarding the existing task plan (taking into account the climate, the relief, the probable orbital conflicts, the available ―external‖ data, the production capability…) , and to establish the corresponding price.

Reference3D ―regular‖

We offer the Reference3D coverage of a pre-determined area, upon the following principles : Technical specifications from the preliminary study Various options are available to customise Reference3D (see below) The delivery calendar is commonly agreed Pricing by sq. km

We will provide : Synthetic report showing the progression of the work upon your zone of interest : every 2 (or 3) months, and under an agreed format (MapInfo, ArcView,…). Reference3D data, following the agreed delivery calendar. Several options available : Each tile is delivered once (ie after completion) Each tile is delivered twice (or more) according to its completion ratio Every 6 (or 12) month, delivery of all the recent ―geometrically correct‖ tiles Any mix of the above…

Depending on your needs, the contract shall include several technical specifications :

The minimum ratio of HRS data within Reference3D ; The maximum ratio of ―no data‖ coverage ; The ―external‖ data that could be used to fill the HRS holes, if any ;

Reference3D ―full‖

Reference3D ―full‖ is an add-on option over the ―regular‖ offer (see above). It allows the user to benefit both from Reference3D and from the HRS stereopairs over his area of interest. This could prove useful for : taking into account very accurate GCPs within a block adjustment process involving very high resolution imagery (2.5m SPOT 5 , Ikonos, QuickBird…) performing sophisticated 3D processes …

One single HRS stereopair encompasses a 120km by 60km area. The processing of HRS stereopairs implies a dedicated sophisticated software. Please note that the content of Reference3D ―full‖ package has nothing to do neither with the design, nor with the procurement, or adaptation, or maintenance of such a software. These matters are to be addressed by the user itself, along with his software provider. We would be glad to help you if needed.

The mode, frequency and schedule of the delivery of HRS stereopairs are to be agreed upon. Many possibilities can be combined within the contract, which must answer the following questions :

Which are the HRS stereopairs provided ? A1 : only the ―useful‖ ones, ie those used (even partly) to build Reference3D A2 : all of the HRS stereopairs acquired over the area during the contract time A3 : A1 + A2, under a cloud-coverage condition (eg : cloud cover < 35%)

When does the procurement of the HRS stereopairs occur ? the HRS pairs are provided only once, ie along with the definitive version of the corresponding tile of Reference3D . All A1, A2, A3 options possible. one update every 2 (or 3, or 4,…) months . All A1, A2, A3 options possible. update every week or fortnight or month. Possible only with A2 , A3 options.

Reference3D licences

User licence

The licensee is granted the right to use the Reference3D product for internal purposes only ; he is not allowed to sell, distribute, loan or otherwise transfer the product to any third party ; he is not allowed to use Reference3D within the processing of marketed value-added product (eg : production of orthoimages for the market).

Business licence

The licensee is granted the right to use, modify and to sell or otherwise transfer the product.

ANNEX #1 Short presentation of HRS instrument and products

The HRS instrument has two telescopes, one pointing forward and one aft of the satellite. The forward-looking sensor acquires images of the ground at a viewing angle of 20° ahead of the vertical. One minute and 30 seconds later, the aft-looking sensor images the same strip at an angle of 20° behind the vertical. The instrument is thus able to cover an area of 600 km x 120 km in a single pass (ie 72 000 km² strips). Over a year, the minimum average acquisition will be 126,000 km2 a day.

Simultaneous stereopair acquisition means better DEM The ability to acquire stereopair images simultaneously is a huge step forward for relief mapping and digital elevation model (DEM) production.

A digital elevation model (DEM) is a digital file, usually containing a uniform grid of terrain elevation values of a region of interest. For example, a DEM might provide an elevation value every 20 metres or every arc second. DEMs are used to generate orthoimages and derive contour files, and to produce slope, insolation and surface runoff maps used to plan sites such as leisure parks and to mitigate natural hazards. DEMs also provide vital information on terrain for aircraft navigation.

Using SPOT 1 to 4, stereopairs have been acquired by imaging the same area from different orbits. Since the resulting images are obviously obtained on different satellite passes, the interval between cloud-free acquisitions can be quite long. This time difference is the chief obstacle when generating a DEM, because the cross-correlation of the two images of the stereopair is the way to map relief. The matching process involves measuring differences that stem only from the different viewing angles, which is of course easier when the images’ radiometric parameters are identical. But the landscape can dramatically change within a few days, as trees lose their leaves, fields are ploughed, soils dry out or soak up moisture, construction projects advance or snow falls. HRS ensures maximum correlation between the two images of the stereopair, since they are acquired just one minute and 30 seconds apart. This key advantage significantly improves DEM quality, and decreases their cost.

No need for GCPs SPOT 5 is carrying a star tracker. This sophisticated instrument points at the stars and recognises constellations to position the satellite with respect to the celestial sphere. It provides very accurate information about the satellite’s attitude (i.e. orientation angles). To fix SPOT 5’s attitude, the star tracker first needs to know the exact position of the satellite along its orbit. This is where the DORIS instrument comes in. DORIS, already used on SPOT 2, SPOT 3 and SPOT 4, calculates the 3D position of the satellite to within centimetres.

The first step of the calibration phase, ended July 2002, shows that the vertical accuracy of HRS DEMs is better than 10m @ 90%, the horizontal accuracy (without GCPs) being 35m, in line with CNES (French Space Agency) expectations. The second step of the calibration phase, dedicated to the fine tuning of geometrical model and system parameters, will end on December 6th 2002. Target value for horizontal accuracy without GCP is 15 m @ 90%, and will be reached only at that time, after precise assessment of in-flight parameters, and using sophisticated processing tools. By comparison, current accuracy with SPOT 1, SPOT 2, SPOT 3 and SPOT 4 is only around 350 to 400 metres. Today, to get round this obstacle and produce accurate DEMs and spacemaps, we have to correct images by tying them to ground control points (GCPs) extracted from topographic maps. This step is vital when SPOT imagery is used as GIS raster basemap, to ensure that other layers register correctly.

So, tying images to GCPs will become a thing of the past, because a 15 meter accuracy is sufficient enough for most of the applications’ needs. That will clear the way for automatic DEM and orthoimage production, the next step towards which Spot Image and IGN are currently working.

HRS builds a world-wide geometric reference

HRS has an expected service lifetime of five years and will cover 6 to 10 million km2 every year, ie. a total of 30 to 50 million km2 in five years —one fifth to one third of the globe’s land masses. HRS stereopairs are acquired systematically over wide areas and will gradually build up a world-wide DEM and orthoimage database named Reference3D. As soon as received from the satellite, each and every HRS stereo strip are validated by IGN teams, (through a strategic operational partnership) to check whether the data is suitable to provide DEM over the whole strip. Invalidated areas (clouds, haze, smoke, snow,…) are reported to the Spot Image tasking unit, which makes the appropriate decision : either tasking HRS again over the missing zones, or find any other source (eg from the Spot archive, or from ASTER, or SRTM…) to fill the gaps. The next step consists in the geometric positioning of the HRS stereo strip via a block-adjustment process, running over large areas ( ± 500 000 km²). Once precisely located, the HRS DTM and orthorectified image data are integrated into Reference3D, along with detailed quality information.

Accurate and affordable orthoimagery

Every Earth Observation data user knows about orthoimages, these very accurate basemaps that integrate easily into a GIS. Through Reference3D and its excellent absolute location accuracy, HRS will be a key player for low-cost orthoimage production, because it will provide a geometric reference to register any image from SPOT 1 to 5, as well as from other sensors. In other words, HRS will help EO users to get rid of control points, thus saving a great deal of time, effort and cost, though they will probably not even suspect the HRS benefit for their 2.5m or 5m SPOT 5 HRG orthoimage.

Today, DEMs (to correct relief displacement effects) and maps (to extract control points) are the main causes for the high cost of orthorectified products. Finding maps is often where most effort is required, since DEM coverage is by no means easy to find outside developed countries. As a matter of fact, the DEM coverage of the Earth is very small. By instance : two per cent of South America and none of Africa ! The coverage is slightly better in fast-developing regions, but the less privileged areas of the world are where it is most needed today. Several systems currently operating can acquire stereoscopic data, but each of them has severe drawbacks. Aerial photography is too costly for wide-area coverages. Radar interferometry is another technique for measuring ground displacements, but which only works well where terrain slopes gently and is sometimes affected by undetectable atmospheric perturbations, a significant source of error. One can also generate DEMs at rather low cost by digitizing existing maps, but available maps often prove of poor quality, hardly acceptable for GIS-based applications.

Thus, thanks to HRS, Spot Image is able to produce DEMs and orthoimages faster, cheaper and better, through this unique and very powerful tool. That will be the outstanding ― HRS advantage‖. World demand for DEMs and orthoimage is huge. So the ability to produce them systematically is bound to nurture new applications and attract new customers.

Multiple applications for orthoimagery

All GIS products on the market today use aerial or satellite imagery to varying degrees. These images must register accurately with other data layers, from statistical, documentary, administrative, socio-economic, geographic and other sources . Corrections for relief displacement, essential for the registration, are made using a HRS DEM with an elevation accuracy of 10 metres, accurate enough outside densely populated urban areas. Mobile phone network planning is currently one area where 3-D data are greatly in demand, but DEMs are also widely used in agriculture, for environmental impact studies and by government mapping agencies. Defence applications are among the biggest users of orthoimagery, which provides vital information for aerial mission planners and command information systems. Combined with DEMs, orthoimages give a detailed picture of terrain relief in future theatres of operations. Consequently, they have become a key asset for low-altitude flight simulations. HRS is thus set to meet a range of as yet unfulfilled requirements, while improving quality and cutting lead times.

The EROS Sensor

The Eros high resolution satellite sensor, launched in December 2000 was designed by Image Sat International which is headquartered in Cypres. Imagesat plans a constellation of 6 hi res satellites by 2004 which will have a panchromatic resolution of 0.8m and 4 multispectral channels at 2.5m resolution. E-LISOSAT currently receives data from the EROS A1 sensor, which only has a panchromatic channel at 1.8m resolution. Eros A1 is also able to capture imagery at 1m resolution in the so called over-sampling mode and can image stereo pairs for high resolution DEM generation. Since Eros can tilt up to 45º, it has a revisit period of 3 days. E-LISOSAT is also a reseller of the only other operational high resolution sensor – IKONOS (1m pan, 4m multispectral), however since E-LISOSAT directly receives data from Eros, we are able to deliver image product for Eros within a matter of days. Although this rapid delivery is charged at a premium, cheaper alternative delivery times are provided for.

Eros scene Coverage

A full Eros scene covers an area of 12.5km x 12.5km and since Eros has an onboard storage facility, it is possible for E-LISOSAT to receive Eros data for anywhere in Africa (see figure 1 for eros scene coverage).

Eros Costs

E-LISOSAT is currently conducting an acquisition plan for Eros imagery. Any imagery acquired from the archive will be charged at $750. In order to search the availability of Eros scenes in the archive visit www. e-Lisosat.co.za or contact customer services (+27 12 334 5100).

For areas of interest which are not covered by archived data, E-LISOSAT will arrange for the programming of the EROS satellite. The cost is $1 500 with a specified delivery time of 90 days (typical delivery time is 2-4 weeks weather permitting). Should the image be clouded, E-LISOSAT will arrange for reimaging of the area up to 3 times within the 3 month period. Only images with less than 10% cloud cover will be invoiced. This arrangement is subject to change at the suppliers discretion.

E-LISOSAT can also arrange for an area to be imaged with a delivery time of 5 days. The client will be invoiced $1500 for the programming of the satellite and $1500 for the image. In this scenario, the risk of cloud cover rests with the client and although the client is not obliged to purchase the clouded image, reimaging will cost a further $1500.

For examples of Eros imager see figures 4 and 5

Agriculture High Resolution Image Applications Civil Government Environmental Exploration/Resources Forestry Insurance & Law Mapping

Media & Entertainment National & Global Security Real Estate Relief & EO Telecommunications Transportation

Utilities

Figure 1. Scene coverages for Landsat 180kmx180km (red), Spot 60kmx60km (tan), Spot 30km x 30km (yellow) and Eros 12.5km x 12.5km (blue), with Gauteng province in backdrop for reference.

Figure 2. Landsat pan merge of JHB North showing Alexandra, Sandton, Hyde Park and Bryanston

Figure 3 Enhanced Spot pan merge of JHB North showing Alexandra, Sandton, Hyde Park and Bryanston

Figure 4 Eros image of Riverclub Golf course

Zoom in on Eros pan 1.8m res (Riverside Golf Course)

Figure 5 Eros image of RDP development outside George

The Ikonos Sensor

Launch Date September 24, 1999 (11:21:08 am PDT)

Launch Vehicle Athena II

Manufacturer Lockheed Martin

Launch Location Vandenberg Air Force Base, California

Viewing angle Agile spacecraft - in-track and cross-track pointing

Weight 725 kg

Altitude 423 miles/681 kilometers

Inclination 98.1 degrees

Speed 4 miles per second/ 7 kilometers per second

Descending nodal 10:30 a.m. crossing time

Orbit time 98 minutes

Orbit type Near-polar, sun-synchronous

Sensor Characteristics

The IKONOS sensor represents a significant step forward in commercial satellite imaging, with an agile spacecraft giving the ability to acquire imagery according to client-specified co-ordinates, 11 bit data and the highest resolution imagery currently commercially available.

Sensors Panchromatic Multispectral

Resolution Ground resolution of each band: 1-meter panchromatic (nominal at <26deg off nadir) 4-meter multispectral (nominal at <26deg off nadir) The ground processing software has the capability to rapidly process and mosaic imagery so as to create seamless image products with a consistent pixel ground sample distance (GSD)

Imagery Spectral Response Panchromatic: 0.45 - 0.90 microns Multispectral: (same as Landsat 4&5 TM Bands #1-4) #1: Blue 0.45 - 0.52 microns #2: Green 0.52 - 0.60 microns #3: Red 0.63 - 0.69 microns #4: Near IR 0.76 - 0.90 microns

Swath Widths Nominal swath width:11 km

Revisit Frequency 2.9 days at 1-meter resolution; 1.5 days at 1.5-meter resolution. These values are for targets at 40 degrees latitude. The revisit times will be more frequent for higher latitudes and less frequent for latitudes closer to the equator.

Viewing Angle Agile spacecraft - in-track and cross-track pointing

Dynamic Range 11-bit data or 8-bit data

Ikonos scene Coverage

Scene Sizes  a nominal single image at 11 km x 11 km  strips of 11km x 100 km up to 11 km x 1000 km  image mosaics of up to 10,000 km2.  up to two 10,000 km2 contiguous areas in a single pass within a region  in-track stereo imagery capability of 22km x 130km perpendicular to the ground track

Ikonos Costs

Ikonos scenes are priced at $2720 or $22.5 per square kilometre where archived scenes are available

Example of 1m pan merge Ikonos image over Dubai

Lidar – Precision high resolution laser DEM, DTM and imagery

E-LISOSAT is proud to announce an addition to its current portfolio of earth observation sensors in the precision high resolution domain. E-LISOSAT recently signed a deal to exclusively distribute very high, resolution precision imagery. ALS perform high speed aerial surveys using aircraft mounted laser scanning systems (LiDAR - Light detection and ranging) and color digital cameras to perform high density aerial surveys. Cutting edge technology in the form of an infrared laser which emits narrow optical pulses, allows for the simultaneous measurement of precision Digital Elevation Models (DEMs) and Digital Terrain Models (DTM). These can be classified into ground and non- ground and even buildings, trees, overhead wires, rails, etc., according to the client’s requirements. In addition, a Kodak DCS 420 or Hasselblad digital camera simultaneously allows for the capture of 24 bit colour imagery tuned to match the swath width of the laser. The resultant product is a rapidly processed precision orthorectified digital colour image of up to 5cm resolution. On board GPS and a state of the art inertial navigation system allows for absolute accuracies of 20cm. Value added products including vector Drawings, surface modelling, contouring, ground profiles and volumes can also be rapidly produced

This technology redefines the concept of high, resolution imagery and its potential offerings, which will now include the land ownership/demarcation, surveying, engineering, mining, security, telecommunications, property evaluation, precision forestry and detailed urban planning sectors. The long term vision is to provide current precision high resolution data from the Lidar system for all the major metropolitan areas in South Africa. Data is already available for Alexandra township in Gauteng as well as 500 000 ha in the Eastern Cape Province and a significant coverage in the North West Province. As demand rises, the system will be web and e-commerce enabled allowing the end user access to the data on his/her proprietary software over the internet. Demand for these data sets is expected to allow entry to the mass market with individual homeowners being able to download images of their properties to the extent that they will be able to calculate exactly how many split pole beams they require for their new fence, or how much topsoil is required to fill a bed for example. Alternatively, the banking councils will be able to make significant savings on property valuations by utilizing the technology and intelligence operations will be able to work out access to suspect properties to the extent of determining the height of a wall which needs to be scaled to 20cm accuracy. ―The obvious advantage of multi users is the fact that data costs can be significantly reduced which fits into the larger E-LISOSAT vision‖

In another deal, E-LISOSAT gained the rights to resell conventional off the shelf, digital orthorectified colour, aerial photography for Cape Town, Bloemfontein, Durban, East London, Port Elizabeth and Gauteng at 50cm resolution. This data set was acquired in 1996, which allows for a baseline against which future high, resolution imagery such as Lidar can be compared for the major metopolitan areas in South Africa. Intelligent archiving systems will allow users to purchase tiles as small as 2.75km x 2.75km, thereby significantly reducing the costs typically associated with high, resolution digital data. This data set will be available form July

3 dimensional image derived from Lidar technology 4cm resolution orthorectified Lidar imagery

Example of Ground and Building top laser data JHB Side view of ground and building top laser data JHB

Lidar image 20cm reolution of Alexandra

Associated Laser points of Alexandra showing building or vegetation in green and ground in brown (all points are absolute accurate to 20cm x,y,z

Contours derived from Lidar (20cm absolute accurate x,y,z)

Drainage patterns derived from lidar (20cm absolute accurate x,y,z)

QuickBird Satellite Images and Sensor Specifications

Because of our relationship with DigitalGlobe, developer and owner of the QuickBird Sensor, Satellite Imaging Corporation (SIC) acquires QuickBird Satellite Imagery worldwide for our customers seeking high-resolution, digital aerial photographs.

QuickBird at Launch; QuickBird in Orbit About the QuickBird Satellite Sensor

QuickBird is a high resolution satellite owned and operated by DigitalGlobe. Using a state-of-the-art BGIS 2000 sensor (PDF), QuickBird collects image data to 0.61m pixel resolution degree of detail. This satellite is an excellent source of environmental data useful for analyses of changes in land usage, agricultural and forest climates. QuickBird's imaging capabilities can be applied to a host of industries, including Oil and Gas Exploration & Production (E&P), Engineering and Construction and environmental studies

QuickBird Satellite Sensor Characteristics Launch Date October 18, 2001 Launch Vehicle Boeing Delta II Launch Location Vandenberg Air Force Base, California, USA Orbit Altitude 450 Km Orbit Inclination 97.2°, sun-synchronous Speed 7.1 Km/sec (25,560 Km/hour) Equator Crossing Time 10:30 AM (descending node) Orbit Time 93.5 minutes Revisit Time 1-3.5 days, depending on latitude (30° off-nadir) Swath Width 16.5 Km x 16.5 Km at nadir Metric Accuracy 23 meter horizontal (CE90%) Digitization 11 bits Pan: 61 cm (nadir) to 72 cm (25° off-nadir) Resolution MS: 2.44 m (nadir) to 2.88 m (25° off-nadir) Pan: 450-900 nm

Blue: 450-520 nm

Image Bands Green: 520-600 nm

Red: 630-690 nm

Near IR: 760-900 nm

Archived or New QuickBird Imagery from the QuickBird Satellite Sensor

For many image requests, a matching image can already be located in the archives of high- resolution QuickBird imagery from around the world. If no image data is available in the archives, new QuickBird satellite image data can be acquired through a satellite tasking process. For more information and pricing, please visit our Contact Us page.

We care and pride ourselves in maintaining a high standard of customer service by sharing our technical know-how and use our worldwide experiences in remote sensing, geodesy, GIS, GPS surveying and mapping. The Satellite Imaging Corporation (SIC) customer support team and senior staff assure that suitable archived image data is identified and ordered or collected through a new tasking order, to meet the project objectives and specifications by providing the following services:

 Negotiations to the attainment of archived or new images with DigitalGlobe  Processing imagery services including orthorectification, color balancing and mosaicing  Advanced Image processing for agriculture, forest, coastal and resource management applications  Extract culture and terrain data in support of GIS and CAD projects  3D Terrain Visualization and modeling for project planning and support  Services to incorporate customer-provided, third party US, and International GIS geospatial data in ESRI's ArcGIS 9.x or other GIS or CAD projects  Consultancy to customers to select band combinations and imaging processing techniques most appropriate to bring out the geographical and manmade features most pertinent to your project. SIC utilizes specialized pansharpening processing techniques to enhance coastal seafloor features and monitor environmental sensitive areas, such as coral zones  Information to customers to assure that correct geodetic and mapping parameters are utilized in support to maintain a "seamless" GIS computer environment for projects involved and to further enhance the spectral analysis for oil and gas, landcover-use classifications, and Environmental Impact Studies (EIS)  New QuickBird satellite image collection at pre-selected time intervals under a subscription tasking program, including attractive pricing discounts, to monitor changes in the environment and progress of construction projects worldwide

WorldView-1 Satellite Sensor

WorldView-1, DigitalGlobe's earth imaging satellite, completed a successful launch from Vandenberg Air Force Base, California, U.S.A., at 11:35 Hrs Pacific Daylight Time (PDT) on September 18th, 2007. The Delta II rocket lifted off in good weather and the WorldView-1 satellite is "currently undergoing a calibration and check-out period," according to DigitalGlobe. The first panchromatic image data should become available before October 18th, 2007.

To view a video of the WorldView-1 satellite launch, click here.

The high-capacity, panchromatic imaging system features half-meter resolution imagery. Operating at an altitude of 496 kilometers, WorldView-1 has an average revisit time of 1.7 days and is capable of collecting up to 750,000 square kilometers (290,000 square miles) per day of half-meter imagery. The satellite is also equipped with state-of-the-art geo-location capabilities and exhibits stunning agility with rapid targeting and efficient in-track stereo collection.

WorldView-1 Satellite Sensor Characteristics Scheduled Launch Date September 18, 2007 Launch Vehicle Boeing Delta 7920 (9-strap-ons) Launch Location Vandenberg Air Force Base, California, USA Orbit Altitude 496 Km Orbit Inclination sun-synchronous 3.6 meters (12 feet) tall x 2.5 meters (8 feet) across, Spacecraft Size, Mass & 7.1 meters (23 feet) across the deployed solar arrays Power 2500 kilograms (5500 pounds) 3.2 kW solar array, 100 Ahr battery Equator Crossing Time 10:30 AM (descending node) 1.7 days at 1 meter GSD or less Revisit Time 5.9 days at 20° off-nadir or less (0.51 meter GSD) Swath Width 17.6 Km at nadir Full Scene 17.6 Km x 14 Km or 246.4 Km 2 at nadir Orbit Time 94.6 minutes Dynamic Range 11 bits per pixel 0.50 meters GSD at nadir

Resolution 0.55 meters GSD at 20° off-nadir (note that imagery must be re-sampled to 0.5 meters for non-US Government customers) Sensor Bands Panchromatic Accuracy: <500 meters at image start and stop Metric Accuracy Knowledge: Supports geolocation accuracy below Specification of 12.2 m CE90, with predicted performance in the range of 3.0 to Geolocation Accuracy 7.6 meters (10 to 25 feet) CE90, excluding terrain and off-nadir effects (CE 90%) With registration to GCPs in image: 2.0 meters (6.6 feet) Acceleration: 2.5 deg/s/s Retargeting Ability Rate: 4.5 deg/s Time to slew 300 kilometers: 9 seconds 3-axis stabilized Attitude Determination Actuators: Control Moment Gyros (CMGs) and Control Sensors: Star trackers, solid state IRU, GPS Onboard Storage 2199 gigabits solid state with EDAC Image and Ancillary Data: 800 Mbps X-band Communications Housekeeping: 4, 16 or 32 kbps real-time, 524 kbps stored, X-band Command: 2 or 64 kbps S-band Max Viewing Angle / 60 x 110 km mono Accessible Ground Swath 30 x 110 km stereo

WorldView-2 Satellite Sensor

DigitalGlobe's WorldView-2 Satellite, launched October 8, 2009, provides 0.5m Panchromatic (B&W) mono and stereo satellite image data. Click here to watch the WorldView-2 launch (courtesy Boeing).

With its improved agility, WorldView-2 is able to act like a paintbrush, sweeping back and forth to collect very large areas of multispectral imagery in a single pass. WorldView-2 alone is able to collect nearly 1 million km2 every day, doubling the collection capacity of our constellation to nearly 2 million km2 per day. And the combination of WorldView-2’s increased agility and high altitude enables it to typically revisit any place on earth in 1.1 days. When added to the satellite constellation, revisit time drops below one day and never exceeds two days, providing the most same-day passes of any commercial high resolution constellation.

The WorldView-2 sensor provides a high resolution Panchromatic band and eight (8) Multispectral bands; four (4) standard colors (red, green, blue, and near-infrared 1) and four (4) new bands (coastal, yellow, red edge, and near-infrared 2), full-color images for enhanced spectral analysis, mapping and monitoring applications, land-use planning, disaster relief, exploration, defense and intelligence, and visualization and simulation environments.

Coastal Band (400 - 450 nm): This band supports vegetation identification and analysis, and supports bathymetric studies based upon its chlorophyll and water penetration characteristics. Also, this band is subject to atmospheric scattering and will be used to investigate atmospheric correction techniques.

Yellow Band (585 - 625 nm): Used to identify "yellow- ness" characteristics of targets, important for vegetation applications. Also, this band assists in the development of "true-color" hue correction for human vision representation. Red Edge Band (705 - 745 nm): Aids in the analysis of vegetative condition. Directly related to plant health revealed through chlorophyll production.

Near Infrared 2 Band (860 - 1040 nm): This band overlaps the NIR 1 band but is less affected by atmospheric influence. It supports vegetation analysis and biomass studies.

The WorldView-2 imaging payload is the second such system engineered and manufactured by ITT Space Systems Division for DigitalGlobe. Once deployed, it will operate at an altitude of 770 kilometers, and the advanced on-board imaging system will capture pan-sharpened, multispectral images (with better than 0.5-meter resolution) from almost 500 miles above the Earth. These images supply unprecedented detail and geospatial accuracy, further expanding the applications for satellite imagery in both commercial and government markets. Added spectral diversity provides the ability to perform precise change detection and mapping.

In addition to numerous other technical improvements, WorldView-2 also has the ability to accommodate direct tasking, which will allow select customers around the world to load imaging profiles directly up to the spacecraft and execute delivery of the data directly down to their own ground stations.

WorldView-2 Satellite Sensor Characteristics Launch Date October 8, 2009

Launch Vehicle Delta 7920 (9 strap-ons)

Launch Site Vandenberg Air Force Base

Orbit Altitude 770 kilometers

Orbit Type Sun synchronous, 10:30 am (LT) descending Node

100 minutes; 7.25 year mission life, including all consumables and Orbit Period degradables (e.g., propellant)

4.3 meters (14 feet) tall x 2.5 meters (8 feet) across, 7.1 meters (23 Spacecraft Size, Mass, & Power feet) across the deployed solar arrays; 2800 kilograms (6200 pounds); 3.2 kW solar array, 100 Ahr battery

Panchromatic Sensor Bands 8 Multispectral (4 standard colors: red, blue, green, near-IR), 4 new colors: red edge, coastal, yellow, near-IR2

Ground Sample Distance Panchromatic: 0.46 meters GSD at Nadir, 0.52 meters GSD at 20° Off-Nadir

Sensor Resolution GSD Multispectral: 1.8 meters GSD at Nadir, 2.4 meters GSD at 20° Off- Nadir (note that imagery must be resampled to 0.5 meters for non-US Government customers) Dynamic Range 11-bits per pixel

Panchromatic - 6 selectable levels from 8 to 64 Time Delay Integration (TDI) Multispectral - 7 selectable levels from 3 to 24

Swath Width 16.4 kilometers at nadir

Attitude Determination and 3-axis stabilized Control

Actuators Control Moment Gyros (CMGs)

Sensors Star trackers, solid state IRU

GPS Position Accuracy & < 500 meters at image start and stop Knowledge Knowledge: Supports geolocation accuracy below Retargeting

1.5 deg/s/s Agility Acceleration Rate: 3.5 deg/s Time to slew 300 kilometers: 9 seconds

2199 gigabits solid state with EDAC Communications Onboard Storage Image and Ancillary Data: 800 Mbps X-band

Housekeeping 4, 16 or 32 kbps real-time, 524 kbps stored, X-band

Command 2 or 64 kbps S-band

Accessible Ground Swath Nominally +/-40° off-nadir = 1355 km wide swath Higher angles selectively available Max Viewing Angle Per Orbit Collection: 524 gigabits Max Contiguous Area Collected in a Single Pass: 96 x 110 km mono, 48 x 110 km stereo

1.1 days at 1 meter GSD or less 3.7 days at 20° off-nadir or less (0.52 Revisit Frequency meter GSD)

(CE 90) Specification of 12.2m CE90, with predicted performance in the range of 4.6 to 10.7 meters (15 to 35 feet) CE90, excluding terrain Geolocation Accuracy and off-nadir effects

With registration to GCP's in image: <2.0 meters (6.6 ft)

For more information on Characterization of Satellite Remote Sensing Systems, please click on the hyperlink.

DigitalGlobe currently operates the QuickBird satellite, which can collect black-and-white, or panchromatic, images with 0.61-meter resolution at Nadir. The satellite, launched in October 2001, also collects multispectral images with 2.5 meter resolution. WorldView-1 high-capacity, panchromatic imaging system features half-meter resolution imagery. Operating at an altitude of 496 kilometers, WorldView-1 has an average revisit time of 1.7 days and is capable of collecting up to 750,000 square kilometers (290,000 square miles) per day of half-meter imagery. The satellite also is equipped with state-of-the-art geo-location accuracy of <2m without GCP's while with one (1) or two (2) GCP's the geospatial accuracy is <1m and further exhibits stunning agility with rapid targeting and efficient in-track stereo collection