[mapserver-users] stretching imagery in MapServer

[Mark Volz]

Andy,

The 2015 leaf off air photos were flown while it was still cold here, which is good because it is easy to identify buildings, but bad because the image is brown.  I had experimented with a couple changes using LUT.  However the Highway Department mentioned that they still prefer the brown images.  Therefore I removed any lut corrections.  

I will try to answer your questions about the server performance tomorrow.


Sincerely,
Mark Volz, GISP
Lyon County GIS Coordinator



> -----Original Message-----
> From: Andy Colson [mailto:andy at squeakycode.net]
> Sent: Wednesday, May 27, 2015 8:50 AM
> To: Mark Volz; Rahkonen Jukka (MML)
> Cc: mapserver-users at lists.osgeo.org
> Subject: Re: [mapserver-users] stretching imagery in MapServer
> 
> Hi Mark.  Two questions for you:
> 
> 1) I know it might be a bunch of extra work, but I don't suppose you could post
> some before and after shots (or urls or whatever).  I really have no idea what
> sort of change your talking about.
> 
> 2) Holy freaking cow you have fast imagery.  I don't suppose you could share
> some processing/hardware/setup secrets?
> 
> Thanks
> 
> -Andy
> 
> 
> On 5/26/2015 2:07 PM, Mark Volz wrote:
> > Jukka, (and others)
> >
> > Thank you for your reply.  I think I figured out how lut works.  If
> > you don't mind please check and make sure I have this correct:
> >
> > I can use ArcGIS to report the correct input and output values for a
> > n=2.5 standard deviation by going to
> > layers->symbology->stretch->histograms->Info window.  Once I have
> > layers->symbology->stretch->histograms->those
> > values I can modify my map file to include for example:
> >
> > PROCESSING "LUT_1=73:0,226:255" #changes red band input of 0-73 to 0,
> > inputs of 226-255 to 255, inputs between 73-226 linearly interpolated.
> >
> > PROCESSING "LUT_2=60:0,199:255" #changes green band input of 0-60 to
> > 0, inputs of 199-255 to 255, inputs between 60-199 linearly interpolated.
> >
> > PROCESSING "LUT_3=35:0,155:255" #changes blue band input of 0-35 to 0,
> > inputs of 155-255 to 255, inputs between 35-155 linearly interpolated.
> >
> > P.S.
> >
> > Before I knew what the heck I was doing with LUT I noticed that I
> > could identify wet areas, and tree cover quite easily with the
> > following
> > combinations:
> >
> > PROCESSING "LUT=50:50,60:250,70:250" is a good way to identify tree
> cover.
> >
> > PROCESSING "LUT=50:50,60:250,70:70"  is a good way to identify wet areas.
> >
> > Thank You
> >
> > Sincerely,
> >
> > *Mark Volz, GISP*
> >
> > *From:*Rahkonen Jukka (MML)
> > [mailto:jukka.rahkonen at maanmittauslaitos.fi]
> > *Sent:* Monday, May 25, 2015 9:18 AM
> > *To:* Mark Volz; mapserver-users at lists.osgeo.org
> > *Subject:* Re: stretching imagery in MapServer
> >
> > Hi,
> >
> > As far as I know automatic stretch by standard deviation is not
> > supported. You can do automatic min-max stretch with PROCESSING
> > "SCALE=AUTO". If your source data is uniform you may reach a good
> > result with manual scale settings or with PROCESSING "LUT=  "
> >
> >
> >
> > -Jukka Rahkonen-
> >
> > Mark Volz wrote:
> >
> > Hello,
> >
> > I added our new Pictometry Air Photos on our mapping site at
> > http://geomoose.lyonco.org/geomoose2/geomoose.html.  The air photos
> > seem somewhat washed out.  In ArcGIS I was able to get a nicer looking
> > image by stretching the air photo using standard deviations. Can we
> > stretch imagery in MapServer?  If not please let me know if you have a
> > comment regarding how I can improve the image quality.
> >
> > Thanks
> >
> > Sincerely,
> >
> > *Mark Volz, GISP*
> >
> >
> >
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> >