INSCOHSTATS

Description

From a set of coregistered interferograms, INSCOHSTATS creates an output file consisting of the average, standard deviation, minimum, and maximum coherence. A time-ordered stack of coherence layers can optionally be appended to the output.

Parameters

inscohstats(mfile, dbic, stack, flsz, filo)

Name	Type	Caption	Length	Value range
MFILE *	str	Input folder, or text file	1 -
DBIC	List[int]	Selected Channel (Default channel 1)	0 -	Default: 1
STACK	str	Stack Data	0 -	yes| no Default: no
FLSZ	List[int]	Filter size (pixels, lines) ODD	0 -
FILO *	str	Database output file name	1 -

* Required parameter

Parameter descriptions

MFILE

The name of a folder, or a text file that contains the list of input interferograms to be processed. Only the PIX file format (*pix) is supported. All files listed in the MFILE or within the input folder pointed to by MFILE must correspond to interferograms generated by INSRAW, INSTOPO, INSADJUST, INSMLOOK or INSMODGOLD. Unwrapped interferograms generated by INSUNWRAP are not supported.

All input files must be co-registered and have the same number of lines and columns.

When MFILE is a text file, it must contain a list of interferograms (one per line) with their full pathname, fore example: MFILE=r"C:/InSAR_project/RAW_neterograms_list.txt"

where the text file contains

C:\InSAR_project\RAW\ref20141028_dep20141215.pix C:\InSAR_project\RAW\ref20141121_dep20141215.pix C:\InSAR_project\RAW\ref20141215_dep20150108.pix C:\InSAR_project\RAW\ref20131009_dep20131126.pix C:\InSAR_project\RAW\ref20131126_dep20131220.pix ...

Alternatively, an input folder can be specified: MFILE = "C:\InSAR_project\RAW"

It is recommended to use wildcards (*) to refine the search within the specified folder, for example:

MFILE = r"C:\InSAR_project\RAW\*.pix"

MFILE = r"C:\InSAR_project\RAW\ref*.pix"

DBIC

This file must not already exist.

STACK

This option indicates whether to include the time-ordered coherence layers in the output PIX file. The layers are sorted in lexicographic order by reference date followed by dependent date.

If STACK="no", only the four statistics layers are returned (see the details section).

FLSZ

FILO

Specifies the name of the PIX file to be generated.

This file must not already exist.

Details

INSCOHSTATS computes coherence statistics for a given series of interferograms. The output file (filo) contains:

• Coherence Average: the average of coherence at each pixel.
• Coherence Standard Deviation: the standard deviation of each pixel.
• Coherence Maximum: the maximum coherency at each pixel from all the interferogram.
• Coherence Minimum: the minimum coherency at each pixel from all the interferogram.

Optionally, when STACK = "YES", the output file (FILO) will also contain the time series of coherence layers used to compute the statistics channels. The output coherence stack is time-ordered based upon the reference and dependent acquisition times as defined by the interferogram's metadata.

INSCOHSTATS accepts wrapped interferograms generated by INSRAW, INSTOPO, INSADJUST, INSMODGOLD and INSMLOOK.

The NoData values (as defined by the "NO_DATA_VAULE" metadata tag) are excluded from the statistical computations.

If the center of the averaging window falls on a NODATA pixel, no statistics are calculated for that pixel. If an averaging window contains NODATA values, they are not used to calculate the statistics of that pixels.

Workflow

INSCOHSTASTS is generally used within the Persistent Scatterers Interferometry workflow (PSI) and requires all interferograms identified by MFILE to be co-registered to a common reference frame with the exact same number of lines and columns.

This is usually accomplished by first ingesting the data (SARINGESTAOI), co-registering the files (INSCOREG) using a single-reference file or the small baselines (SBAS) technique and then generating the interferograms (INSRAW) for co-registered pairs of reference and dependent data.

Examples

Generate the coherence statistics layers, with no filtering, using a list of RAW interferograms.

from pci.inscohstats import inscohstats

mfile   =  "mfile.txt"    				#List of raw interferograms files
dbic	= []								#selecting channel, default 1st channel
stack    =  "no"                      		#process default ""=no, only statistics
flsz    =  []                       		#no filter
filo    =  "INSCOHSTATS_stats.pix"		#output containing the raster layers

inscohstats(mfile, dbic, stack, flsz, filo)
        

Generate a pix file with a 5x5 filter containing only the statistics channels.

from pci.inscohstats import inscohstats

mfile   =  "mfile.txt"    				#List of raw interferograms files
dbic	= []								#selecting channel, default 1st channel
stack    =  ""                      		#process default "no", only statistics
flsz    =  [5]                      		# 5 x 5 filter
filo    =  "INSCOHSTATS_stats.pix"      #output containing the raster layers

inscohstats(mfile, dbic, stack, flsz, filo)
        

Generate a pix file with a 5x7 filter containing only the statistics channels.

from pci.inscohstats import inscohstats

mfile   =  "mfile.txt"    				#List of raw interferograms files
dbic	= []								#selecting channel, default 1st channel
stack    =  ""                      		#process default ""=no, only statistics
flsz    =  [5,7]                   			#rectangular 5x7 filter size
filo    =  "INSCOHSTATS_5x7_stats.pix"  #output containing the raster layers

inscohstats(mfile, dbic, stack, flsz, filo)
        

Generate a pix file with a 5x5 filter containing the statistics channels and the time-ordered series of coherence layers.

from pci.inscohstats import inscohstats

mfile   =  "mfile.txt"    				#List of raw interferograms files
dbic	= []								#selecting channel, default 1st channel
stack    =  "yes"                      		#append temporally ordered coherence layers
flsz    =  [5,5]                   			#rectangular 5x5 filter size
filo    =  "INSCOHSTATS_5x5_stack.pix"  #output containing the raster layers

inscohstats(mfile, dbic, stack, flsz, filo)
        

Generate a pix file containing the statistics channels from channel 2, could be from any valid channel.

from pci.inscohstats import inscohstats

mfile   =  "mfile.txt"    				#List of raw interferograms files
dbic	= [2]								#selecting channel 2, could be any valid channel
stack    =  "no"                      		#process default ""=no, only statistics
flsz    =  []                       		#no filter
filo    =  "INSCOHSTATS_ch_2_def.pix" 	#output containing the raster layers

inscohstats(mfile, dbic, stack, flsz, filo)