Topic: overlay of velocity vector on study area

I am working on one of the glacier in India. I have trying to overlay the velocity vector on the subset image of study area but the I guess the direction of the velocity vectors are not oriented correctly, means some velocity vector are going uphill rather than coming down. What can be the possible error??

I have done image to image registration of the subset images of LANDSAT TM images then find the correlation. After that I masked the results whose SNR < 0.9.

Kindly help.


Re: overlay of velocity vector on study area


make sure to check that the correlation map that you obtained makes sense. For instance check if the displacements on areas outside the glacier are close to zero. Also, you might have spurious measurements on the glacier that are incorrect (even with high SNR) and cause the displacement to be oriented upslope. These should be easily identified and discarded.