What is the best way to make real colour images from Landsat bands?

January 22, 2006 5:41 PM

What is the best way to make real colour images from Landsat bands?

The images I've created by merging the first three bands as RGB channels in Photoshop look very washed out, or have a strong red tint. Photoshop's auto-levels and auto-colour seems to help, but presumably then the colours are not true. Does anyone know of a better (or the correct) method?

posted by richard m to science & nature (3 comments total)

Here's a pretty good tutorial on just that.

The primary hints seems to be:

Select Image>Levels, and adjust each channel independently of the others. This will give you the most control over the output.

So, yeah, you have to manually adjust the colors, it seems.

Apprenently this filter is suppose to help, too.

I'm guess as with most things you'll just have to play with it until you get something right. In my personal experiences of playing with GIS data, I always just have to tweak it to suite my uses.

Are you going to be doing this in bulk or just a few one-off instances?
posted by killThisKid at 7:10 AM on January 23, 2006

You can get good and rapid results by using MultiSpec opening the first band's file (it will appear in black and white). Then going back to the open dialog and selecting Link to active image window, then select the next band you want to add and then click open...the file selection dialog will reappear and you can select the third band. Then click cancel. From the Processor menu select Display Image... and then set your band combination to 3, 2, 1 and click ok. You can then save the file being displayed out to a GeoTiff from the File->Save menu.

That should do a pretty good job and give you a better place to start tweaking the levels in photoshop.

FYI, the reason the raw tif's look so bad when first opened is that you are looking at raw sensor data that is not histogram stretched. There are some settings you can play around with in MultiSpec that will let you tweak things too.

Also, MultiSpec is a program that is used for doing classifications of remote sensing images (Landsat, SPOT, MODIS etc.), it is freely available and pretty good/quick at what you need to do.
posted by jduckles at 7:47 AM on January 23, 2006

Thanks so much Jonah! Multispec is giving me great results so far.
posted by richard m at 9:54 AM on January 23, 2006