6

1 - I have two scenes Landsat-8 RGB 6/5/4 and I need to mosaic them:

Landsat-8 scenes

2- This is my cutline in polygon format that will smooth the overlapping area:

Landsat-8 polygon cutline

3 - So, I need to create a mosaic with feathering like ERDAS or ENVI applications. This is my goal:

Landsat-8 mosaic with cutline and feathering

It's possible to make this in QGIS, GDAL or another opensource software?

  • Feathering would imply that you want to use blurring along the borders. Is that the case? Or do you only want to use the polygon cutlines? – underdark Dec 21 '14 at 14:17
  • Yes, Anita. I need to apply a feathering to smooth the overlapping area this way: bit.ly/1wRRpkc – Jorge Santos Dec 21 '14 at 14:24
  • 1
    OSSIM can do feathering trac.osgeo.org/ossim. – user30184 Dec 22 '14 at 9:39
  • 2
    We are currently developing such an algorithm for GRASS GIS, so please stay tuned... However, histogram matching is already there: grass.osgeo.org/grass70/manuals/addons/i.histo.match.html – markusN Dec 22 '14 at 22:31
  • user30184, please send me a step by step for OSSIM program. – Jorge Santos Dec 24 '14 at 11:50
2

Like mentioned before, you might want to try OSSIM. It is a series of commandline programs and one or two GUI's. I am currently trying that out. There is no option to use a cutline as far as I know.

Information about OSSIM: http://trac.osgeo.org/ossim

Installers can be found at: http://download.osgeo.org/ossim/installers

The current GUI is called Geocell. You can find a video tutorial here http://www.youtube.com/watch?v=66wUXo95yp0

Imagelinker is a GUI that is not being updated anymore, although it does come along with the current Osgeo4W installer. But you can still take a look at tutorials for some guidance.

The only unpleasant thing about OSSIM is you have to setup elevation and preferences. But with some persistance, you get everything running. Please keep me updated on your progress. Would like to see what works best for you.

4

I am a developer of the open-source GIS Whitebox GAT, which contains several image processing tools including a tool called Mosaic With Feathering. I doubt that it is as sophisticated as ERDAS or ENVI tools, but it will create a seamless mosaic using a feathering scheme.

enter image description here

A detailed description of the process can be found in the linked tutorial. You can use the Find Tie Points tool to automatically identify tie points between the images that you are mosaicing if they are not geo-registered. I should mention as well that you will likely have to mosaic the individual bands prior to creating a colour composite image.

Here is an example of a Landsat 8 band 753 colour-composite without seamless mosaicing:

enter image description here

And here is the same image with the use of the Mosaic With Feathering tool:

enter image description here

The tool applies histogram matching to the images to further improve the mosaic and the Create Colour Composite tool will apply a balance contrast enhancement (BCE) to the individual bands when you combine the mosaiced bands to form a colour composite image. The feathering during the mosacing is based on a distance-weighted scheme but there is no 'cut line' and you do not need to specify any input image polygons.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.