Re: [GRASS-user] Matching Histograms for Aerial Photography?

2017-06-21 Thread Moritz Lennert 

On 21/06/17 08:03, Jeshua Lacock wrote:



On Jun 20, 2017, at 6:02 AM, Moritz Lennert  
wrote:

You can try the addon: i.histo.match. You can install it with g.extension.


Hi Moritz,

Thanks for the suggestion. Currently the data is raster - I assume I will have 
to convert it to imagery?



imagery = raster. To be more precise, imagery is raster data in which 
pixel values are physical camera-like sensor values. But in terms of 
format they are identical, so no need to convert.




I tried installing the extension, but it fails with an SSL certificate error. I 
don’t see anyway to ignore or use a non-secure transfer.


I really cannot help you with that error. What you can do, however, is 
download the addon as a zip file from [1] and install directly from that 
zip with g.extension [...] url=/path/to/zipfile


Moritz

[1] 
https://trac.osgeo.org/grass/browser/grass-addons/grass7/imagery/i.histo.match?format=zip



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Re: [GRASS-user] Matching Histograms for Aerial Photography?

2017-06-20 Thread Jeshua Lacock 
Sorry for the duplicate; I posted the other message after waiting over 6 hours 
for this message to post (which ultimately took about 24 hours).
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Re: [GRASS-user] Matching Histograms for Aerial Photography?

2017-06-20 Thread Moritz Lennert 

On 20/06/17 11:06, Jeshua Lacock wrote:


Greetings,

I am struggling to match histograms for various US states NAIP 1-meter
aerial photography.

It appears that each state shown here has been equalized for each
individual state except for Nevada and Arizona.

I have tried using r.rescale.eq with many different parameters but I
cannot really get Nevada and Arizona to roughly match the intensities of
the rest of the states. It is difficult to guess values that match
because the images are quite large and when I attempt to use a thumbnail
(say at 50m resolution), the parameters used for the 50m thumbnail don’t
match when using the full resolution image.

Can anyone recommend how I might be able to get the histograms to match?


You can try the addon: i.histo.match. You can install it with g.extension.

Moritz
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