Remote Sensing & Mineral Exploration By Keiko Hamam & Sylvia Michael GEOIMAGE Pty Ltd.
Download ReportTranscript Remote Sensing & Mineral Exploration By Keiko Hamam & Sylvia Michael GEOIMAGE Pty Ltd.
Slide 1
Remote Sensing & Mineral Exploration
By Keiko Hamam & Sylvia Michael
GEOIMAGE Pty Ltd
Slide 2
Presentation Overview
• Brief introduction to Satellite Remote Sensing
• Resolutions – Spatial, Spectral, Temporal &
Radiometric
• Which satellite is best for me?
• What if my area has no archive imagery?
• What if my area of interest is constantly covered by
cloud ? - a brief introduction to Radar Data
• Case Study: The use of ALOS Imagery in Mineral
Exploration – Pakistan, including
• How to collect or supply GCP’s
• Orthorectification
• DEMs from Satellite Imagery
• Accuracy of Data
• Software
• Questions
Slide 3
Remote Sensing Introduction
• Satellites capture imagery as digital raster datasets
• Electro-optical sensors capture energy in different
electromagnetic wavelengths or bands from the visible, near
infrared, short-wave infrared and thermal infrared
• Different ground covers reflect or absorb energy in different
wavelengths
Slide 4
Remote Sensing Introduction - Useful Bands
Visible Blue:(0.450.52 um)
Best penetration
for clear water,
poor penetration
through haze
Near Infra Red (NIR): (0.77-1.30 um)
Determines biomass content,
delineates water bodies
Visible Green:
(0.52-0.60 um)
Vegetation vigour
assessment
Visible Red: (0.63-0.69 um)
Vegetation discrimination, high iron
oxide reflectivity
Short Wave Infra Red (SWIR): (1.306.00 um) Determines soil moisture
content, discrimination of rock types,
hydrothermal clay mapping
Slide 5
Remote Sensing Introduction - Resolutions
• SPATIAL
• SPECTRAL
• TEMPORAL
• RADIOMETRIC
Slide 6
Spatial Resolution
• The smallest feature that is distinguishable on an image is
determined by the spatial resolution, the XY dimensions of each
pixel
© Space Imaging 2003
© CNES 2004
Slide 7
Spatial Resolutions
SPOT 5 10-metre false colour left, 5-metre panchromatic right
© CNES
Slide 8
Spatial Resolutions
SPOT 5 5-metre panchromatic left, 2.5-metre panchromatic right
© CNES
Slide 9
Spatial Resolutions
SPOT 5 10-metre false colour left, 2.5-metre pan-sharpened pseudo-natural
colour right
© CNES
Slide 10
Spectral Resolution
• Spectral Resolution refers to the number of different
electromagnetic wavelength bands recorded by the
sensor
Panchromatic or black and
white imagery is acquired by a
digital sensor that measures
energy reflectance in one wide
portion of the electromagnetic
spectrum. For most current
panchromatic sensors, this
single band usually spans the
visible to near-infrared part of
the spectrum.
Slide 11
Spectral Resolution
Multispectral imagery is
acquired by a digital sensor that
measures reflectance in a
number of bands. Current
optical multispectral remote
sensing satellites can
simultaneously measure
reflectance in three to fourteen
different bands.
Slide 12
Spectral Resolution
RGB
Landsat
321
RGB
Landsat
432
RGB
Landsat
543
Slide 13
Spatial and spectral resolutions of commonly used highand medium- resolution electro-optical satellites
QuickBird
0.61m Pan (Visible to NIR), 2.44m Multi (B, G, R, NIR)
IKONOS
0.82m Pan (Visible to NIR), 3.28m Multi (B, G, R, NIR)
SPOT 5
2.5m Merged Pan (Visible), 5m Pan (Visible),
10m Multi (G, R, NIR, SWIR)
ALOS
2.5m PRISM (Visible to NIR), 10m AVNIR-2 (B, G, R, NIR)
SPOT 4
10m Pan (Visible), 20m Multi (G, R, NIR, SWIR)
SPOT 2
10m Pan (Visible), 20m Multi (G, R, NIR)
ASTER
15m 3 bands VNIR, 30m 6 bands SWIR, 90m 5 bands TIR
Landsat 7
15m Pan (Visible to NIR), 30m Multi (B, G, R, NIR, 2 bands
SWIR), 60m TIR
Landsat 5
30m Multi (B, G, R, NIR, 2 bands SWIR), 60m TIR
Slide 14
Temporal Resolution
• Temporal resolution is defined by the revisit
capabilities of the satellite
For example, Landsat 5 and 7 revisit the same
location every 16 days. Off-nadir viewing satellites,
including IKONOS, QuickBird and SPOT can be
programmed to revisit a location every few days.
Slide 15
Temporal Resolution
29 November 2001
21 December 2001
Slide 16
Temporal Resolution
30 December 1999
25 June 2001
Slide 17
Temporal Resolution
Change in Band 7
Slide 18
Radiometric Resolution
• Radiometric resolution is defined by the number of
greyscale values recorded in each band by the sensor
For example, ALOS, SPOT and Landsat have 8-bit or
single byte data. IKONOS and QuickBird have 11-bit
data.
Slide 19
Radiometric Resolution
8 Bit – 256 shades of grey
11 Bit – 2048 shades of grey
8 Bit imagery – suitable for GIS applications
11 Bit Imagery – suitable for Remote Sensing + Processing applications
Slide 20
Which satellite is best for me?
Questions to consider:
Regional exploration, prospect exploration or mine
site planning?
Amount of vegetation cover?
Suitability of age of archived imagery?
Availability of imagery?
Slide 21
Applications of high resolution imagery
• Base maps for planning of prospect exploration and
development work and mine site planning
• Planning of access roads and utilities into remote locations
• Targeting prospect areas for further exploration based on
topographic features
• Identification of previous exploration work
• Seismic planning and field operations
• Detailed identification of drainage for geochemical sampling
• Production of high-resolution digital elevation models
Slide 22
Applications of medium resolution imagery
• Regional overview of large areas
• Mapping of major geologic units
• Determination of regional structures
• Mapping recent volcanic surface deposits
• Spectral processing using Landsat and ASTER
• Extensive archive of imagery, particularly Landsat
• Small cost for large area coverage
• Production of medium-resolution digital elevation models
Slide 23
What if my area has no archive imagery?
Satellites available for programming:
• SPOT 2, 4 and 5
• IKONOS
• QuickBird
• Radarsat
Slide 24
What if my area is constantly covered by cloud?
Electro-optical sensors are passive imaging instruments that
measure electromagnetic energy emitted by the sun and
reflected off the Earth’s surface.
Synthetic Aperture Radar (SAR) sensors actively transmit a
radar signal in the microwave portion of the spectrum and
measure the strength and other characteristics of the return
signal reflected off the Earth’s surface. Because SAR is active
and operates in longer wavelengths, it can acquire images
through cloud, fog, haze and darkness.
Slide 25
What if my area is constantly covered by cloud?
SAR sensors measure the roughness of the surface compared
to the radar wavelength transmitted.
The most common wavelengths used are L-band or 235 mm
(JERS and PALSAR) and C-band or 56 mm (Radarsat, ERS and
Envisat).
Slide 26
What if my area is constantly covered by cloud?
PALSAR image of Darwin
Landsat 7 image of Darwin
Slide 27
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
At Koh-i-Sultan, Lake Resources is exploring an
extensive system of intensely altered volcanics on
the margin of an extinct caldera in a Quaternary age
compound andesitic stratovolcano.
Slide 28
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Aims:
• 5-metre DEM contours to plan access for a drill rig
• Stereo hardcopy for interpretation at 1:25,000
scale
ALOS data purchases included:
• 10-metre AVNIR-2 acquired 2 October 2006
• 2.5-metre PRISM triplet i.e. backward, nadir and
forward-looking, acquired 17 August 2006
Slide 29
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
ALOS AVNIR-2 acquired
2 October 2006
Visible bands shown in
blue, green, red
No geometric correction
applied
Slide 30
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
ALOS PRISM acquired
17 August 2006
Forward, nadir,
backward
No geometric correction
applied
Slide 31
From raw to end product – Collection of Ground
Control
• Most types of raw satellite imagery require some form of
geometric correction or rectification so that the imagery will
correspond to real world map projections and coordinate
systems
• Geometric rectification improves the horizontal positional
accuracy of the imagery by warping the data to match
identifiable features (Ground Control Points) from coordinated
imagery or airphotos, maps, vectors or dGPS points
• Each ground control point should be identifiable as a single
pixel on the image to be rectified
Slide 32
From raw to end product – Collection of Ground
Control
A good spread of ground control points within each
individual scene and in overlapping areas will provide a
good rectification result.
Slide 33
From raw to end product – Rectification and
Orthorectification
• For areas where there is undulating topography, or if the
imagery has been captured at a high angle to the vertical, or
very high accuracy is required, orthorectification is necessary
• Orthorectification is rectification that incorporates a digital
elevation model (DEM) to correct for distortions due to
capture angle and topographic relief
• Orthorectification is also recommended for pan-sharpening
imagery where the higher resolution panchromatic data is not
captured in conjunction with the lower resolution multispectral
Slide 34
From raw to end product – Rectification and
Orthorectification
An accurate and detailed DEM will improve the internal
locational accuracy of each pixel.
Slide 35
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
• Accurate ground control was only available
for the immediate area of the caldera
• Systematic orthorectification of the nadir
PRISM using the Geocover Landsat 7 Pan and
the Shuttle Radar Topography Mission (SRTM)
DEM
Slide 36
Digital Elevation Models (DEMs) from Satellite
Imagery
• DEMs from satellite imagery
are produced by in- or crosstrack stereo
ASTER VNIR and ALOS PRISM
(right) have in-track stereo
and SPOT has cross-track
stereo.
The agile IKONOS satellite
has a combination of both inand cross-track stereo.
Slide 37
Digital Elevation Models (DEMs) from Satellite
Imagery
ASTER VNIR band 3N on left and band 3B on right showing coincident GCPs in red
Slide 38
Digital Elevation Models (DEMs) from Satellite
Imagery
Epipolar images from previous ASTER datasets, left and right
Slide 39
Digital Elevation Models (DEMs) from Satellite
Imagery
Resultant DEM before editing
Slide 40
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Epipolar images from backward-forward PRISM pair, left and right
Slide 41
Accuracy of Data
• The accuracy of the final DEM or imagery is very
dependent on the accuracy of the ground control in
X, Y and Z space and needs to match the spatial
resolution of the imagery
For example, Geocover Landsat 7 Pan is a good
control base for imagery with a spatial resolution of
15+ metres, as it has a quoted accuracy of +/-50
metres. System corrected IKONOS and QuickBird
both have an accuracy of +/-23 metres, excluding
terrain effects, and therefore the ground control base
should have a better accuracy than this.
Slide 42
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
AVNIR-2 Visible
Blue, Green, Red
Orthorectified full
scene
70 km by 70 km
Slide 43
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Nadir PRISM
Orthorectified full
scene
35 km x 35 km
Slide 44
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Pan-sharpened
AVNIR-2 Visible
Blue, Green, Red
Coincident Scene
35 km x 35 km
Slide 45
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Pan-sharpened
AVNIR-2 Visible
Blue, Green, Red
right half and
AVNIR-2 Blue,
Green, Red left half
~2 km by 2 km
Slide 46
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
• The systematically orthorectified ALOS nadir
PRISM was used for control of the AVNIR-2
• The pan-sharpened AVNIR-2 was shifted to
match supplied ground control over the caldera
• The accuracy of the DEM can only be
assessed using the automatically generated
drainage
Slide 47
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Resultant DEM
35 km by 35 km
Slide 48
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Resultant DEM
showing generated
drainage vectors
35 km by 35 km
Slide 49
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Resultant ALOS DEM with contours on the left and the SRTM DEM on the right
Slide 50
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Using the ALOS imagery and DEM, we were able to
supply the required 2-5-metre pan-sharpened imagery,
pseudo-stereo hardcopy for interpretation at 1:25,000
scale, a 10-metre DEM and 5-metre contours. In
addition the data was found to be of better quality
than expected and exceeded our client’s expectations.
Slide 51
Software
• At Geoimage, we use, sell and support two of the
major image processing packages, ER Mapper Pro
and PCI Geomatics.
ER Mapper Pro is an intuitive desktop package for
the processing of raster imagery. The package allows
rectification of satellite imagery and orthorectification
of air photos. We use it for geocoding, image
compression and general image processing.
Slide 52
Software
PCI Geomatics is an advanced image processing
package for remote sensing, digital photogrammetry,
spatial analysis and cartographic editing. We use it
for orthorectification of satellite imagery as it models
the satellite parameters and DEM generation. For the
case study, we also used PCI for production of a flow
accumulation image from which vector drainage lines
were automatically generated.
Slide 53
SPECTRAL PROCESSING OF ASTER DATA
ASTER VNIR bands 3, 2, 1 in red, green, blue on left
ASTER SWIR bands 5+6+7+8, VNIR bands 3, 1 in red, green and blue on right
Slide 54
SPECTRAL PROCESSING OF ASTER DATA
ASTER decorrelated SWIR bands 7, 6, 5 in red, green, blue on left
Highest predicted clay minerals on an albedo image on the right
Slide 55
Thank you
www.geoimage.com.au
Remote Sensing & Mineral Exploration
By Keiko Hamam & Sylvia Michael
GEOIMAGE Pty Ltd
Slide 2
Presentation Overview
• Brief introduction to Satellite Remote Sensing
• Resolutions – Spatial, Spectral, Temporal &
Radiometric
• Which satellite is best for me?
• What if my area has no archive imagery?
• What if my area of interest is constantly covered by
cloud ? - a brief introduction to Radar Data
• Case Study: The use of ALOS Imagery in Mineral
Exploration – Pakistan, including
• How to collect or supply GCP’s
• Orthorectification
• DEMs from Satellite Imagery
• Accuracy of Data
• Software
• Questions
Slide 3
Remote Sensing Introduction
• Satellites capture imagery as digital raster datasets
• Electro-optical sensors capture energy in different
electromagnetic wavelengths or bands from the visible, near
infrared, short-wave infrared and thermal infrared
• Different ground covers reflect or absorb energy in different
wavelengths
Slide 4
Remote Sensing Introduction - Useful Bands
Visible Blue:(0.450.52 um)
Best penetration
for clear water,
poor penetration
through haze
Near Infra Red (NIR): (0.77-1.30 um)
Determines biomass content,
delineates water bodies
Visible Green:
(0.52-0.60 um)
Vegetation vigour
assessment
Visible Red: (0.63-0.69 um)
Vegetation discrimination, high iron
oxide reflectivity
Short Wave Infra Red (SWIR): (1.306.00 um) Determines soil moisture
content, discrimination of rock types,
hydrothermal clay mapping
Slide 5
Remote Sensing Introduction - Resolutions
• SPATIAL
• SPECTRAL
• TEMPORAL
• RADIOMETRIC
Slide 6
Spatial Resolution
• The smallest feature that is distinguishable on an image is
determined by the spatial resolution, the XY dimensions of each
pixel
© Space Imaging 2003
© CNES 2004
Slide 7
Spatial Resolutions
SPOT 5 10-metre false colour left, 5-metre panchromatic right
© CNES
Slide 8
Spatial Resolutions
SPOT 5 5-metre panchromatic left, 2.5-metre panchromatic right
© CNES
Slide 9
Spatial Resolutions
SPOT 5 10-metre false colour left, 2.5-metre pan-sharpened pseudo-natural
colour right
© CNES
Slide 10
Spectral Resolution
• Spectral Resolution refers to the number of different
electromagnetic wavelength bands recorded by the
sensor
Panchromatic or black and
white imagery is acquired by a
digital sensor that measures
energy reflectance in one wide
portion of the electromagnetic
spectrum. For most current
panchromatic sensors, this
single band usually spans the
visible to near-infrared part of
the spectrum.
Slide 11
Spectral Resolution
Multispectral imagery is
acquired by a digital sensor that
measures reflectance in a
number of bands. Current
optical multispectral remote
sensing satellites can
simultaneously measure
reflectance in three to fourteen
different bands.
Slide 12
Spectral Resolution
RGB
Landsat
321
RGB
Landsat
432
RGB
Landsat
543
Slide 13
Spatial and spectral resolutions of commonly used highand medium- resolution electro-optical satellites
QuickBird
0.61m Pan (Visible to NIR), 2.44m Multi (B, G, R, NIR)
IKONOS
0.82m Pan (Visible to NIR), 3.28m Multi (B, G, R, NIR)
SPOT 5
2.5m Merged Pan (Visible), 5m Pan (Visible),
10m Multi (G, R, NIR, SWIR)
ALOS
2.5m PRISM (Visible to NIR), 10m AVNIR-2 (B, G, R, NIR)
SPOT 4
10m Pan (Visible), 20m Multi (G, R, NIR, SWIR)
SPOT 2
10m Pan (Visible), 20m Multi (G, R, NIR)
ASTER
15m 3 bands VNIR, 30m 6 bands SWIR, 90m 5 bands TIR
Landsat 7
15m Pan (Visible to NIR), 30m Multi (B, G, R, NIR, 2 bands
SWIR), 60m TIR
Landsat 5
30m Multi (B, G, R, NIR, 2 bands SWIR), 60m TIR
Slide 14
Temporal Resolution
• Temporal resolution is defined by the revisit
capabilities of the satellite
For example, Landsat 5 and 7 revisit the same
location every 16 days. Off-nadir viewing satellites,
including IKONOS, QuickBird and SPOT can be
programmed to revisit a location every few days.
Slide 15
Temporal Resolution
29 November 2001
21 December 2001
Slide 16
Temporal Resolution
30 December 1999
25 June 2001
Slide 17
Temporal Resolution
Change in Band 7
Slide 18
Radiometric Resolution
• Radiometric resolution is defined by the number of
greyscale values recorded in each band by the sensor
For example, ALOS, SPOT and Landsat have 8-bit or
single byte data. IKONOS and QuickBird have 11-bit
data.
Slide 19
Radiometric Resolution
8 Bit – 256 shades of grey
11 Bit – 2048 shades of grey
8 Bit imagery – suitable for GIS applications
11 Bit Imagery – suitable for Remote Sensing + Processing applications
Slide 20
Which satellite is best for me?
Questions to consider:
Regional exploration, prospect exploration or mine
site planning?
Amount of vegetation cover?
Suitability of age of archived imagery?
Availability of imagery?
Slide 21
Applications of high resolution imagery
• Base maps for planning of prospect exploration and
development work and mine site planning
• Planning of access roads and utilities into remote locations
• Targeting prospect areas for further exploration based on
topographic features
• Identification of previous exploration work
• Seismic planning and field operations
• Detailed identification of drainage for geochemical sampling
• Production of high-resolution digital elevation models
Slide 22
Applications of medium resolution imagery
• Regional overview of large areas
• Mapping of major geologic units
• Determination of regional structures
• Mapping recent volcanic surface deposits
• Spectral processing using Landsat and ASTER
• Extensive archive of imagery, particularly Landsat
• Small cost for large area coverage
• Production of medium-resolution digital elevation models
Slide 23
What if my area has no archive imagery?
Satellites available for programming:
• SPOT 2, 4 and 5
• IKONOS
• QuickBird
• Radarsat
Slide 24
What if my area is constantly covered by cloud?
Electro-optical sensors are passive imaging instruments that
measure electromagnetic energy emitted by the sun and
reflected off the Earth’s surface.
Synthetic Aperture Radar (SAR) sensors actively transmit a
radar signal in the microwave portion of the spectrum and
measure the strength and other characteristics of the return
signal reflected off the Earth’s surface. Because SAR is active
and operates in longer wavelengths, it can acquire images
through cloud, fog, haze and darkness.
Slide 25
What if my area is constantly covered by cloud?
SAR sensors measure the roughness of the surface compared
to the radar wavelength transmitted.
The most common wavelengths used are L-band or 235 mm
(JERS and PALSAR) and C-band or 56 mm (Radarsat, ERS and
Envisat).
Slide 26
What if my area is constantly covered by cloud?
PALSAR image of Darwin
Landsat 7 image of Darwin
Slide 27
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
At Koh-i-Sultan, Lake Resources is exploring an
extensive system of intensely altered volcanics on
the margin of an extinct caldera in a Quaternary age
compound andesitic stratovolcano.
Slide 28
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Aims:
• 5-metre DEM contours to plan access for a drill rig
• Stereo hardcopy for interpretation at 1:25,000
scale
ALOS data purchases included:
• 10-metre AVNIR-2 acquired 2 October 2006
• 2.5-metre PRISM triplet i.e. backward, nadir and
forward-looking, acquired 17 August 2006
Slide 29
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
ALOS AVNIR-2 acquired
2 October 2006
Visible bands shown in
blue, green, red
No geometric correction
applied
Slide 30
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
ALOS PRISM acquired
17 August 2006
Forward, nadir,
backward
No geometric correction
applied
Slide 31
From raw to end product – Collection of Ground
Control
• Most types of raw satellite imagery require some form of
geometric correction or rectification so that the imagery will
correspond to real world map projections and coordinate
systems
• Geometric rectification improves the horizontal positional
accuracy of the imagery by warping the data to match
identifiable features (Ground Control Points) from coordinated
imagery or airphotos, maps, vectors or dGPS points
• Each ground control point should be identifiable as a single
pixel on the image to be rectified
Slide 32
From raw to end product – Collection of Ground
Control
A good spread of ground control points within each
individual scene and in overlapping areas will provide a
good rectification result.
Slide 33
From raw to end product – Rectification and
Orthorectification
• For areas where there is undulating topography, or if the
imagery has been captured at a high angle to the vertical, or
very high accuracy is required, orthorectification is necessary
• Orthorectification is rectification that incorporates a digital
elevation model (DEM) to correct for distortions due to
capture angle and topographic relief
• Orthorectification is also recommended for pan-sharpening
imagery where the higher resolution panchromatic data is not
captured in conjunction with the lower resolution multispectral
Slide 34
From raw to end product – Rectification and
Orthorectification
An accurate and detailed DEM will improve the internal
locational accuracy of each pixel.
Slide 35
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
• Accurate ground control was only available
for the immediate area of the caldera
• Systematic orthorectification of the nadir
PRISM using the Geocover Landsat 7 Pan and
the Shuttle Radar Topography Mission (SRTM)
DEM
Slide 36
Digital Elevation Models (DEMs) from Satellite
Imagery
• DEMs from satellite imagery
are produced by in- or crosstrack stereo
ASTER VNIR and ALOS PRISM
(right) have in-track stereo
and SPOT has cross-track
stereo.
The agile IKONOS satellite
has a combination of both inand cross-track stereo.
Slide 37
Digital Elevation Models (DEMs) from Satellite
Imagery
ASTER VNIR band 3N on left and band 3B on right showing coincident GCPs in red
Slide 38
Digital Elevation Models (DEMs) from Satellite
Imagery
Epipolar images from previous ASTER datasets, left and right
Slide 39
Digital Elevation Models (DEMs) from Satellite
Imagery
Resultant DEM before editing
Slide 40
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Epipolar images from backward-forward PRISM pair, left and right
Slide 41
Accuracy of Data
• The accuracy of the final DEM or imagery is very
dependent on the accuracy of the ground control in
X, Y and Z space and needs to match the spatial
resolution of the imagery
For example, Geocover Landsat 7 Pan is a good
control base for imagery with a spatial resolution of
15+ metres, as it has a quoted accuracy of +/-50
metres. System corrected IKONOS and QuickBird
both have an accuracy of +/-23 metres, excluding
terrain effects, and therefore the ground control base
should have a better accuracy than this.
Slide 42
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
AVNIR-2 Visible
Blue, Green, Red
Orthorectified full
scene
70 km by 70 km
Slide 43
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Nadir PRISM
Orthorectified full
scene
35 km x 35 km
Slide 44
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Pan-sharpened
AVNIR-2 Visible
Blue, Green, Red
Coincident Scene
35 km x 35 km
Slide 45
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Pan-sharpened
AVNIR-2 Visible
Blue, Green, Red
right half and
AVNIR-2 Blue,
Green, Red left half
~2 km by 2 km
Slide 46
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
• The systematically orthorectified ALOS nadir
PRISM was used for control of the AVNIR-2
• The pan-sharpened AVNIR-2 was shifted to
match supplied ground control over the caldera
• The accuracy of the DEM can only be
assessed using the automatically generated
drainage
Slide 47
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Resultant DEM
35 km by 35 km
Slide 48
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Resultant DEM
showing generated
drainage vectors
35 km by 35 km
Slide 49
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Resultant ALOS DEM with contours on the left and the SRTM DEM on the right
Slide 50
Case Study: The Use of ALOS Imagery in
Mineral Exploration, Pakistan
Using the ALOS imagery and DEM, we were able to
supply the required 2-5-metre pan-sharpened imagery,
pseudo-stereo hardcopy for interpretation at 1:25,000
scale, a 10-metre DEM and 5-metre contours. In
addition the data was found to be of better quality
than expected and exceeded our client’s expectations.
Slide 51
Software
• At Geoimage, we use, sell and support two of the
major image processing packages, ER Mapper Pro
and PCI Geomatics.
ER Mapper Pro is an intuitive desktop package for
the processing of raster imagery. The package allows
rectification of satellite imagery and orthorectification
of air photos. We use it for geocoding, image
compression and general image processing.
Slide 52
Software
PCI Geomatics is an advanced image processing
package for remote sensing, digital photogrammetry,
spatial analysis and cartographic editing. We use it
for orthorectification of satellite imagery as it models
the satellite parameters and DEM generation. For the
case study, we also used PCI for production of a flow
accumulation image from which vector drainage lines
were automatically generated.
Slide 53
SPECTRAL PROCESSING OF ASTER DATA
ASTER VNIR bands 3, 2, 1 in red, green, blue on left
ASTER SWIR bands 5+6+7+8, VNIR bands 3, 1 in red, green and blue on right
Slide 54
SPECTRAL PROCESSING OF ASTER DATA
ASTER decorrelated SWIR bands 7, 6, 5 in red, green, blue on left
Highest predicted clay minerals on an albedo image on the right
Slide 55
Thank you
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