Topic: General Information
Firstly, i would like to point out that i am a new user of the CosiCorr. I am trying to determine the mass movements by cosicorr. However, i have got some questions. I would be too pleased if you could answer them.
I have got two ASTER (L1A *.hdf) images in two different periods. I want to determine the mass movements(about 5-10 meters) between two periods related to study area.
First of all, i wonder the answer of these questions.
I think we should use GCPS (5-6 GCPs in two images by Image to Image) in stead of orthorectification by ancillary file (about accuracy of 100 meters). We need also to a good DEM. Generally, you should suggest the shaded DEM for orthorectifying. We can have some difficulties to determine location of the tie points in shaded DEM. On the other hand, in case of having the high resolution data (quickbird image, orthophoto or toposheet), can we use them for converting from tie points to GCPs? If we use them, Do we encounter any problems? During the orthorectification, if needed, which one of the optimized GCPS or GCPS should we use with DEM?
In correlation file or nlmfiltered file, Data represents what (in Cursor/Location Value window),and what is its unit (metre or pixel)? For example, what does it mean in case of data:-12.125171.
Processes performing for my study
1. I applied the orthorectifications (by using ASTER GDEM) for images in two periods without GCPS.
2. I have the correlation file and it appears good.
3. I applied the filter the SNR Band of the correlation file (between 0.9 and 1)Discard / Replace images values
4. I defined subset area in the region without NaN values and determined the h parametre for nlmfilter.
4. Although i applied nlmfilter for EW and NS bands, i have still some NaN values. How can we get rid of these NaN values?
5. Should i apply the destripe image for nlmfiltered image? if it should be, which one of files should we select for Automatic Orientation (in image destriping / undulation removal)
Thank you in advance.