airminex aster minmap brochure
TRANSCRIPT
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8/12/2019 Airminex ASTER MinMap Brochure
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---------Javier Prado Oeste 1445, Dpto 702, San Isidro Lima 27. Telfono (51-1)2216679. Telefax (51-1)221-6634---------------
AirMinEx Standard ASTER Mineral Maps
Corresponding to
INGEMMET 1:100,000-Scale Geology Series
ASTER image data have been processed for much of Peru and the resultant alteration mineralmaps have been compiled into a series of GISs in both MapInfo and Arc-GIS format covering
individual 1:100,000-scale, quarter degree quadrangles. The ASTER imagery has been used to
create a Digital Elevation Model (DEM) at a spatial resolution of 30m and this in turn has been
used to orthorectify the spectral image data. This DEM is also used to create both colour and
greyscale shaded relief images which form the lower layers of the overall GIS (Figure 1).
Figure 1; Examples of the greyscale and colour shaded reliefimages that form the base of the GIS.
Figure 2; Semi transparent geology image drapedon the greyscale shaded relief image.
An image of the geology for the quadrangle or map sheet is also imported into the GIS so that the
geology can be related to topography and structures as well as to any alteration mineralogy that
has been mapped (figure 2).
Above the DEM layers are a series of image layers representing the intensity or probability of the
presence of individual alteration minerals and general alteration styles (figure 3). The alteration
minerals mapped comprise jarosite, goethite, hematite, silica, pyrophyllite, alunite, dickite,
kaolinite, high-AlOH illite, low-AlOH illite, chlorite, epidote, dolomite and calcite and the
alteration styles mapped are ferruginous; silicic, advanced argillic, argillic, phyllic, propylitic and
carbonate. These intensity images essentially measure the closeness of match in the pixel
spectrum relative to the reference spectrum for each mineral or style and hence can be interpreted
as representing either the relative purity of the mineralogy in a pixel or the relative probability.
The lower limit of the colour scaled zones represents the level of spectral matching where there is
no evidence at all for the presence of that particular mineral or style. Vector polygon layers for
each of the mapped minerals and styles overlie all of the raster intensity layers and the limit of
each vector polygon is at the lower limit of the colour scaled raster image (figure 3).
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8/12/2019 Airminex ASTER MinMap Brochure
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---------Javier Prado Oeste 1445, Dpto 702, San Isidro Lima 27. Telfono (51-1)2216679. Telefax (51-1)221-6634---------------
0% probability 100% probability
Figure 3; Intensity image for the mineral kaolinite, top
left, and the vector layer overlain top right with the
relative scaling for the intensity image bottom left.
The vector polygons for the individual minerals and alteration styles are placed in order of their
relative extents with the more extensive minerals positioned below the less extensive ones so that
all alteration minerals present in any given system may be viewed without any single layer being
obscured (figure 4).
Figure 4; All alteration mineral vector polygon layers
shown over combined shaded relief and greyscale
albedo image (top left) and combined shaded relief
and geology image (top right) with an example of the
information tool showing the assemblage at any one
point (bottom left and arrow).
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8/12/2019 Airminex ASTER MinMap Brochure
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---------Javier Prado Oeste 1445, Dpto 702, San Isidro Lima 27. Telfono (51-1)2216679. Telefax (51-1)221-6634---------------
This layering also has the advantage that when any given point is queried, the entire alteration
mineral assemblage indicated for that point is revealed (figure 4). These individual mineral
distributions can then be viewed relative to one and other in terms of their intensities as well as
relative to the topography and to the geology (figure 4). Finally; additional image algorithms such
as a grey scale albedo image and the equivalent of a Landsat TM 7-4-2 rgb image are provided forpossible photo-geologic interpretive purposes along with comprehensive legends for the mineral
mapping, topography and geology (figures 5 and 6).
Figure 5; ASTER 6-3-1 rgb equivalent of the Landsat TM 7-4-2 rgb image, draped on greyscale shaded relief.
Current coverage available is shown in figure 7 and map sheets that are as yet incomplete can be
prepared in advance of our planned schedule on request and at the same price as those currently
available.
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8/12/2019 Airminex ASTER MinMap Brochure
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---------Javier Prado Oeste 1445, Dpto 702, San Isidro Lima 27. Telfono (51-1)2216679. Telefax (51-1)221-6634-
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8/12/2019 Airminex ASTER MinMap Brochure
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---------Javier Prado Oeste 1445, Dpto 702, San Isidro Lima 27. Telfono (51-1)2216679. Telefax (51-1)221-6634---------------
Figure 7; Current map sheets covered and planned.
The same procedures and products can also be prepared over customer-designated areas either
within a map sheet or covering a number of map sheets. Furthermore, such customized products
need not conform to map sheet boundaries. For further information and costings for such
customized products please contact us.