Hello
I am trying to compare two SAR images taken from Sentinel-1 .
They have the same configuration ,same Eval ,same location ,same Orbit .
The only difference is the date ,12 days b/w each image.
However ,the images are not the same.
I know for certain ,that there was no physical change to that location.
How can you explain this difference b/w the images?
Btw ,I took more than two samples ,and more than two time periods.
Thank you
Please share some examples that we can compare. Either EO Browser links or the request bodies you used including time and location.
In addition, do bear in mind that while satellite imagery is great for automating the detection of land cover change over large areas, the results are typically not as accurate or precise what you would get from measurements directly in the field.
Multiple reasons could be behind the differences in the images; change that you are unaware, the angle of data acquisition, the time of day.
Thanks for your response.
In regards to “the angle of data acquisition, the time of day”
Doesn’t the Satellite go over the same location in the exact time(and angle) the following time it revisits that location?
Generally, yes this is the case but many areas of interest will actually overlap with different orbits. For example, in an example area of interest you can see here that the two acquisitions have different orbits, contrasting orbit directions and very different times of day.
This isn’t the case in every single situation, but when running change detection on satellite imagery, it should always be accepted that there will be false positives as well as false negatives too.
Again thank you for your response.
But ,in the examples you provided ,one is Descending ,and the other is Ascending ,which would obviously cause a difference.
I am referring to a situation where both are the same. Why should there be any difference?
Regards
This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.
