INSSTACK

Description

INSSTACK generates velocities, displacements, or cumulative displacements for non-overlapping time steps corresponding to consecutive SAR acquisition times. INSSTACK supports line-of-sight measurements (LOS) from single stack output and geodetic (vertical, longitudinal (east/west)) from multi-stack output.

Parameters

insstack(fili, oquant, dispdir, dunits, tunits, filo)

Name	Type	Caption	Length	Value range
FILI*	str	Database input file name	1 -
OQUANT	str	Output quantity	0 -	VEL | DISP | CDIS | AVER Default: CDIS
DISPDIR	str	Displacement direction	0 -	LOS | VERT | LONG Default: LOS
DUNITS	str	Distance units	0 -	MM | CM | M | IN | FT Default: M
TUNITS	str	Time units	0 -	DAT | YEAR Default: YEAR
FILO*	str	Database output file name	1 -

* Required parameter

Parameter descriptions

FILI

The name of the file containing the single stack LOS displacements from INSDMV or decomposed multi-stack displacements generated by INSGEODISP. The displacement values must be written in meters.

OQUANT

Specifies the output parameter.

DISPDIR

DUNITS

The distance units used to measure the displacement.

TUNITS

The time units used to measure the time interval used for velocity estimates. This unit is also used as the X axis by the InSAR temporal chart tool.

FILO

The name of the output PCIDSK (.pix) which will contain the estimated displacements, cumulative displacements, or velocities corresponding to the time intervals bracketed by the temporally ordered acquisition dates.

The specified output file must not already exist.

Details

INSSTACK reads the stack of temporally ordered, non-overlapping displacements corresponding to each acquisition interval and converts them to velocity, displacement, or cumulative displacement in user defined units. For single stack input generated by INSDMV the output is written in the line-of-sight (LOS) direction. For multi-stack input generated by INSGEODISP, the output may be written in the vertical direction (up is positive) or the longitudinal direction (east is positive). If OQUANT is set to CDIS, the cumulative displacement for each layer is written. If OQUANT is set to AVER, the output will consist of a single layer of average velocity. The average velocity is calculated as the cumulative displacement divided by the reference stack time interval. The units selected for DUNITS and TUNITS are also used as the X and Y axis by the InSAR temporal chart tool.

Examples

The following example reads the file of temporally ordered, non-overlapping, LOS displacements generated by INSDMV to provide temporally ordered layers of LOS velocity. The output will be measured in centimeters per year.

from pci.insstack import insstack

fili = r"D:\INSDMV_Displacements.pix"
oquant = "VEL"
dispdir = "LOS"
dunits = "CM"
tunits = "YEAR"
filo = r"D:\Velocity.pix"
insstack(fili, oquant, dispdir, dunits, tunits, filo)
      

The following example uses the output from INSGEODISP generate cumulative vertical (up positive) displacement in millimeters.

from pci.insstack import insstack

fili = r"D:\INSGEODISP_Displacements.pix"
oquant = "CDISP"
dispdir = "VERT"
dunits = "MM"
tunits = "YEAR"
filo = r"D:\Vertical.pix"
insstack(fili, oquant, dispdir, dunits, tunits, filo)
      

The following example uses the output from the same INSGEODISP file to generate cumulative longitudinal (east positive) displacement in millimeters.

from pci.insstack import insstack

fili = r"D:\INSGEODISP_Displacements.pix"
oquant = "CDISP"
dispdir = "LONG"
dunits = "MM"
tunits = "YEAR"
filo = r"D:\Vertical.pix"
insstack(fili, oquant, dispdir, dunits, tunits, filo)