If you can interpolate and organize the data as follows, I can
incorporate it fairly painlessly;
/* not real data */
sensor= Spot 2
band= 3 hvr2
Lower edge wavelength = 0.715
Upper edge wavelength = 0.9175
Spectral Response =
.0000, .0001, .0001, .0002, .0004, .0005, .0007, .0009
.0012, .0014, .0017, .0021, .0024, .0028, .0032, .0036
.0040, .0045, .0054, .0065, .0080, .0112, .0170, .0245
.0330, .0450, .0740, .0990, .1520, .2140, .3050, .4200
.5970, .6750, .7900, .8270, .8400, .8408, .9010, .9050
.9100, .9140, .9050, .9260, .9470, .9670, .9760, .9840
.9710, .9790, .9880,1.0000, .9902, .9840, .9780, .9710
.9470, .9510, .9450, .9380, .9340, .9300, .9360, .9420
.9140, .8970, .7980, .7000, .5970, .4610, .3700, .2630
.1730, .1259, .0888, .0619, .0450, .0346, .0267, .0207
.0160, .0120, .0086, .0060, .0040, .0025, .0013, .0003
.0000
Note that;
(Upper edge wavelength - lower edge wavelength)/2.5nm should equal the
number of elements in the Spectral response.
(Lower edge wavelength - 250nm)/2.5nm should be a integer. ie 250,
257.5 & 260 not 251,258.5 & 261.
Linear interpolation is probably the safest, but bilinear should be
fine. I'd plot the "before" and "after" one on top of the other to
make sure there are no major deviations between the two. If you're
familiar with, I found using Octave/matlab and interp1 to greatly
simplify things. In the mean time I'll try to figure out GeomCond.cpp
so I can simply submit a patch.
Cheers,
Mike
On 28-Jul-09, at 5:23 PM, andrew haywood wrote:
Hi Mike
thanks for this supporting information. I will start the
interpolation. Is there any prefered method for this? Can I use a
bilinear approach.
I think this is as far as I can take it though - as I have no
understanding of lwave.cpp and the file construct. Will it be ok to
post a txt file on the list with the interpretation results?
Cheers
Andrew
On 7/29/09, Michael Perdue <[email protected]> wrote:
Hi Andy,
Yes, it looks like the right info for the SPOT sensor platforms.
Iwave.cpp expects the data to be in 2.5nm increments so you will
have to interpolate the data to the correct interval. It's a bit
tedious, but is straight forward. I might be able to dedicate some
time to it, but won't have any till the weekend now.
Cheers,
Mike
On 27-Jul-09, at 10:35 PM, andrew haywood wrote:
Hi All,
Im just adding to this discusssion. I would be interested in using
i.atcorr with SPOT 2, 3, 4 and 5. I have found a file on the http://www.spotimage.com/web/en/555-spot-images.php
website that contains the spectral sensitivity data. Is this the
same as the spectral profile? It looks like the data is in 5nm
increments. Do i need to create 2.5nm increments or can i tell the
function its in 5nm or 10nm increments?
Any help would be appreciated.
thanks
Andy
On 7/28/09, Michael Perdue <[email protected]> wrote:
Hi Markus,
Here is a text file with everything organized as I think it should
be. I didn't add the this Iwave.cpp to submit a patch as I wasn't
really sure how to modify GeomCond.cpp.
Cheers,
Mike
On 26-Jul-09, at 1:34 PM, Markus Neteler wrote:
Great - the header of Iwave.cpp contains instructions how to add
a new sensor like this.
thanks
Markus
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