[GRASS-user] Pan sharpen Worldview-2 imagery

William Hudspeth bhudspeth at edac.unm.edu
Tue Aug 16 10:56:43 PDT 2016

Hello Nikos,

The link you provided documents how to use g.extension for installing 
python scripts in GRASS 7.3. In particular, it uses the 'url=....' 
argument to specify a link to a zip file. I am using the stable version 
of GRASS 7.0 that is installed with Ubuntu 16.01. In that version, the 
'url=...' argument is not available. Is there an alternative way to 
install your extension in GRASS 7.0?

Thanks much, William

On 08/13/2016 11:23 PM, Nikos Alexandris wrote:
> William Hudspeth:
>> Hello,
> Hello William,
>> I was wondering whether anyone has a workflow to pan sharpen Worldview-2
>> imagery (0.5 m pan, and 2.0 m MS) with 5 bands (panchromatic, red, blue,
>> green, NIR).
>> I am using grass 7.0.3 on ubuntu 16.01, but cannot find the
>> i.fusion.hbf command. I would also like information on any
>> pre-processing I might need to perform, such as converting digital
>> number to reflectance.
> A simple workflow, would be to *first*, ortho-rectify your images
> based on their own RPCs. You might want to read this à propos:
> http://fwarmerdam.blogspot.ch/2013/09/exploring-rpcs.html
> Next, you can create a Location based on the image's own reference
> system, like:
> grass70 -c WorldView2_Image.TIF /projects/grassdb/location_name
> of course, you would (re-)name the above as it fits for you.
> Now, inside GRASS,
> 1. import bands (pan and multispectral) in grass' data base using 
> `r.in.gdal` -- bands will
> likely get a basename (the one given for `output=`, and a number as a
> suffix if the number of bands is more than 3, I think).
> 2. optionally, rename for the imported multispectral bands their names 
> to easier
> know which is which (like instead of ".1" , "blue" or whatsoever fits).
> 3. you may want to use
> https://github.com/NikosAlexandris/i.worldview.toar to convert digital
> numbers to radiance or reflectance. An example command:
> i.worldview.toar
> band=11APR03001446-M2AS_R1C1.Blue,11APR03001446-M2AS_R1C1.Green,11APR03001446-M2AS_R1C1.Red,11APR03001446-M2AS_R1C1.NIR 
> outputsuffix=Rad utc=2011-04-03T00:14:46.590888Z sea=44.1
> 4. Then you can use i.fusion.hpf to sharpen all multispectral bands in
> one go like:
> i.fusion.hpf pan=Panchromatic msx=msRed,msBlue,msGreen,msNIR
> given, of course, the appropriate band names.
>> Any assistance is much appreciated...
>> Thanks
> You might want to have a look at
> https://grasswiki.osgeo.org/wiki/WorldView and assist in cleaning it up
> and improving it.
> Nikos

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