MintPy mainly uses attribute names from ROI_PAC, with some additional self-generated attributes.

#### Required attributes

If using ROI_PAC as the InSAR processor, both baseline parameter RSC file (i.e. 100416-100901_baseline.rsc) and basic metadata file (i.e. filt_100416-100901-sim_HDR_4rlks_c10.unw.rsc) will be imported into MintPy. The following attributes for each interferogram are required in order to run MintPy:

- LENGTH = number of rows.
- WIDTH = number of columns.
- X/Y_FIRST = (for geocoded product) Longitude/easting/X and latitude/northing/Y coordinate in degrees/meters of the upper left corner of the first pixel.
- X/Y_STEP = (for geocoded product) Ground resolution in degrees/meters in X/Y direction.
- X/Y_UNIT = (for geocoded product) Coordinate unit in X/Y direction: degrees or meters.
- LAT/LON_REF1/2/3/4 = Latitude/northing and longitude/easting at corner 1/2/3/4 (in degrees or meters), used in save_unavco, PyAPS (DEM file in radar coord), not accurate; number named in order of first line near/far range, last line near/far range.
- WAVELENGTH = Radar wavelength in meters.
- RANGE_PIXEL_SIZE = Slant range pixel size (search for pixel_ratio to convert to ground size, in m), used in dem_error, incidence_angle, multilook, transect.
- EARTH_RADIUS = Best fitting spheroid radius in meters, used in dem_error, incidence_angle, convert2mat.
- CENTER_LINE_UTC = Time at middle of interferogram in seconds, used in tropo correction using PyAPS.
- HEIGHT = Height of satellite in meters, used in dem_error, incidence_angle, convert2mat.
- STARTING_RANGE = Distance from satellite to first ground pixel in meters, used in incidence_angle calculation
- PLATFORM = satellite/sensor name, used in Local Oscillator Drift correction for Envisat.
- ORBIT_DIRECTION = ascending, or descending.
- ALOOKS/RLOOKS = multilook number in azimuth/range direction, used in weighted network inversion.

The following attributes vary for each interferogram:

- DATE12 = (date1)-(date2), reference - secondary date of interferogram in 6 digit number.
- P_BASELINE_TOP_HDR = Perpendicular baseline at top (first line) of interferogram in meters.
- P_BASELINE_BOTTOM_HDR = Perpendicular baseline at bottom (last line) of interferogram in meters.

#### Optional attributes

- ANTENNA_SIDE = -1 for right looking radar, used in save_unavco
- AZIMUTH_PIXEL_SIZE = Azimuth pixel size at orbital altitude (multiply by Re/(Re+h) for ground size (m), where Re is the local earth radius), used in baseline_error/trop and multilook.
- HEADING = Spacecraft heading at peg point (degrees), measured from the north with clock-wise as positive, used in asc_desc
- PRF = Pulse repetition frequency (Hz), used in save_unavco

#### Self-generated attributes

- FILE_TYPE = file type.
  - for HDF5 files, it’s the root level dataset name, such as `velocity, timeseries, ifgramStack, temporalCoherence, mask, HDFEOS, dem, coherence, etc.`;`
  - for binary files, it’s the file extension name, such as `.unw, .cor, .int, .amp, .mli, .dem, .hgt, .unw.conncomp, .UTM_TO_RDC, .trans, etc.`, except for ISCE geometry files, which is the file base name such as `hgt, lat, lon, los, shadowMask, incLocal`.
- FILE_PATH = absolute file path
- PROCESSOR = processing software, i.e. isce, aria, snap, gamma, roipac etc.
- DATA_TYPE = data type, i.e. float32, int16, etc., for isce product read using GDAL
- BYTE_ORDER = order of bytes, or endianness, for binary files, i.e. big-endian or little-endian. Most InSAR processors use little-endian, except for Gamma, which sometimes use big-endian.
- BANDS = number of bands, for binary file I/O.
- INTERLEAVE = band interleave type, i.e. BSQ, BIL, BIP for binary file I/O.
- NO_DATA_VALUE = No data value, value that should be ignored.
- UNIT = data unit, i.e. m, m/yr, radian, and 1 for file without unit, such as coherence [source]
- REF_DATE = reference date
- REF_X/Y = column/row of the reference point
- REF_LAT/LON = latitude/northing and longitude/easting of the reference point (in degrees or meters)
- SUBSET_XMIN/XMAX/YMIN/YMAX = start/end column/row number of subset in the original coverage
- MODIFICATION_TIME = dataset modification time, exists in ifgramStack.h5 file for 3D dataset, used for “–update” option of unwrap error corrections.
- NCORRLOOKS = number of independent looks, as explained in SNAPHU
- UTM_ZONE = UTM zone, comprises a zone number and a hemisphere, e.g. 11N, 60S, for geocoded file with UTM projection only.
- EPSG = EPSG code for coordinate systems, for geocoded files only. Check here for its relationship with UTM zone.
- CENTER_INCIDENCE_ANGLE = incidence angle in degrees at the scene center, read from the 2D incidence angle matrix, for isce2 files only.

#### Reference

- Pritchard et al., (2014), Open-source software for geodetic imaging: ROI_PAC for InSAR and pixel tracking, pp 44-48. PDF

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