[mapserver-users] Re: displaying ERDAS .img files with mapserver

[Puneet Kishor]

On Nov 10, 2011, at 2:48 PM, Puneet Kishor wrote:

> Additionally, my rendered image is grayscale. How can I apply a color ramp to this image? For example, instead of from white to black, I would like it to be from white to red or black to yellow (or whatever). Is there a way to do this without having to specify a color value for each of the 256 pixels?

A few days ago I asked the above question, but got no reply.

Then, yesterday I saw the following email


On Nov 17, 2011, at 2:00 PM, Mark Volz wrote:

> Hello,
> 
> I recently found a post http://www.osgeo.org/pipermail/mapserver-users/2011-October/070461.html that shows how add a nice DEM gradient in a map.  I was wondering if it would be possible to display a gradient based on the current extent of the map.  This would be very similar to how you can use the current display extent in ArcGIS when the symbology type is set to stretched.  In other words, I would like the color ramp to be based of the current extent.

which led me to http://www.osgeo.org/pipermail/mapserver-users/2011-October/070461.html where I learned about COLORRANGE and DATARANGE. I used those keywords and now I have a color ramp, and although I can guess the meaning of the syntax from the usage, I really don't have any official documentation on those directives.

The interesting thing is, the thread referenced in the link above has the following comment

>> On Fri, Oct 14, 2011 at 5:49 PM, Smith, Michael ERDC-CRREL-NH 
>> <Michael.Smith at usace.army.mil<mailto:Michael.Smith at usace.army.mil
>> wrote:
>> John
>> 
>> The DATARANGE / COLORRANGE keywords will be fully documented by 6.2 but they have been 
>> present in MapServer for years (since 4.6 or so).


Really! Have those directives really been unavailable since version 4.6, but won't be "officially" available until 6.2 (assuming that the existence of documentation implies official availability).


--
Puneet Kishor