Compensated Phase History Data (sarkit.cphd)

Python reference implementations of the suite of NGA.STND.0068 standardization documents that define the Compensated Phase History Data (CPHD) format.

Supported Versions

• CPHD 1.0.1

• CPHD 1.1.0

Data Structure & File Format

FileHeaderPart(*[, additional_kvps])	CPHD header fields which are set per program specific Product Design Document
Metadata(*[, file_header_part])	Settable CPHD metadata
Reader(file)	Read a CPHD file
Writer(file, metadata)	Write a CPHD file
read_file_header(file)	Read a file header.
binary_format_string_to_dtype(format_string)	Return the numpy.dtype corresponding to a binary format string.
dtype_to_binary_format_string(dtype)	Return the binary format string corresponding to a numpy.dtype.
mask_support_array(array[, nodata_hex])	Apply a NODATA hex string to a support array to mask the array.

Per Vector Parameters

dtype_to_pvp_element(ns, dtype)	Return a CPHD/PVP XML element describing structured datatype dtype.
get_pvp_dtype(cphd_xmltree)	Get a structured datatype for the Per Vector Parameter set defined in cphd_xmltree.
get_defined_pvp_dtype(ns)	Get a structured datatype containing all defined PVPs from the requested namespace.

XML Metadata

High-level classes and methods

XmlHelper(element_tree)	XmlHelper for CPHD
ElementWrapper(elem[, xsdhelper, ...])	ElementWrapper for CPHD that can set xsdhelper automatically.
XsdHelper(root_ns)	XsdHelper for CPHD

Transcoders for defined XML parameter types

TxtType()	Transcoder for text (TXT) XML parameter types.
EnuType()	Transcoder for enumeration (ENU) XML parameter types.
BoolType()	Transcoder for boolean (BOOL) XML parameter types.
XdtType([force_utc])	Transcoder for XML dateTime (XDT) XML parameter types.
IntType()	Transcoder for integer (INT) XML parameter types.
DblType()	Transcoder for double-precision floating point (DBL) XML parameter types.
HexType()	Transcoder for HEX XML parameter types.
LineSampType([child_ns])	Transcoder for XML parameter types containing scalar Line and Sample components.
XyType([child_ns])	Transcoder for XML parameter types containing scalar X and Y components.
XyzType([child_ns])	Transcoder for XML parameter types containing scalar X, Y, and Z components.
LatLonType([child_ns])	Transcoder for XML parameter types containing scalar Lat and Lon components.
LatLonHaeType([child_ns])	Transcoder for XML parameter types containing scalar Lat, Lon, and HAE components.
PolyType(*[, child_ns])	Transcoder for one-dimensional polynomial (POLY) XML parameter types.
Poly2dType(*[, child_ns])	Transcoder for two-dimensional polynomial (2D_POLY) XML parameter types.
XyzPolyType([child_ns])	Transcoder for XYZ_POLY XML parameter types containing triplets of 1D polynomials.
PvpType()	Transcoder for per-vector parameter (PVP) XML parameter types.

Derived/convenience transcoders

AddedPvpType()	Transcoder for added per-vector parameter (APVP) XML parameter types.
DefinedPvpType(format_string)	Transcoder for per-vector parameter (PVP) XML parameter types with a fixed size and format.
ImageAreaCornerPointsType()	Transcoder for CPHD-like SceneCoordinates/ImageAreaCornerPoints XML parameter types.
ParameterType()	Transcoder for TXT XML parameter types with a required "name" attribute.

CPHD Signal Model

compute_t_ref(xmt, rcv, srp, txc, trc)	Compute the reference times for the given collection geometry parameters.
compute_t_ref_from_pvps(pvp_array)	Compute the reference times for each vector in a PVP array.

Scene Coordinates & Collection Geometry

Image Reference Surface

planar_ecf_to_iac(pt, iarp, uiax, uiay)	Convert from ECF coordinates to IAC coordinates for Surface Type = PLANAR
planar_iac_to_ecf(pt_iac, iarp, uiax, uiay)	Convert from IAC coordinates to ECF coordinates for Surface Type = PLANAR
hae_llh_to_iac(pt_llh, iarp_llh, uiax_ll, ...)	Convert from geodetic LLH coordinates to IAC coordinates for Surface Type = HAE
hae_iac_to_llh(pt_iac, iarp_llh, uiax_ll, ...)	Convert from IAC coordinates to geodetic LLH coordinates for Surface Type = HAE

Convenience functions that operate on parsed XML trees:

ecf_to_iac(cphd_xmltree, pt)	Convert from ECF coordinates to IAC coordinates
iac_to_ecf(cphd_xmltree, pt_iac)	Convert from IAC coordinates to ECF coordinates
llh_to_iac(cphd_xmltree, pt_llh)	Convert from geodetic LLH coordinates to IAC coordinates
iac_to_llh(cphd_xmltree, pt_iac)	Convert from IAC coordinates to geodetic LLH coordinates

Reference Geometry Parameters

compute_reference_geometry(cphd_xmltree, pvps)

Return a CPHD/ReferenceGeometry XML element containing parameters computed from other metadata.

Constants

VERSION_INFO	dict of {xml namespace: version-specific information}
DEFINED_HEADER_KEYS	set of KVP keys defined in the standard
SECTION_TERMINATOR	Two-byte sequence that marks the end of the file header

CLI Utilities

cphdinfo

Display information about CPHD files

usage: cphdinfo [-h] [--xml] [--channels] [--raw {XML,SUPPORT,PVP,SIGNAL}]
                filename

filename

-h, --help

show this help message and exit

--xml, -x

Extract XML formatted for display

--channels, -c

List channels

--raw {XML,SUPPORT,PVP,SIGNAL}

Extract raw bytes of a BLOCK

References

CPHD 1.0.1

[NGA.STND.0068-1_1.0.1_CPHD]

National Center for Geospatial Intelligence Standards, “Compensated Phase History Data (CPHD) Design & Implementation Description Document, Version 1.0.1”, 2018. https://nsgreg.nga.mil/doc/view?i=4638

[CPHD_schema_V1.0.1_2018_05_21.xsd]

National Center for Geospatial Intelligence Standards, “Compensated Phase History Data (CPHD) XML Schema, Version 1.0.1”, 2018. https://nsgreg.nga.mil/doc/view?i=4639

CPHD 1.1.0

[NGA.STND.0068-1_1.1.0_CPHD_2021-11-30]

National Center for Geospatial Intelligence Standards, “Compensated Phase History Data (CPHD) Design & Implementation Description Document, Version 1.1.0”, 2021. https://nsgreg.nga.mil/doc/view?i=5388

[CPHD_schema_V1.1.0_2021_11_30_FINAL.xsd]

National Center for Geospatial Intelligence Standards, “Compensated Phase History Data (CPHD) XML Schema, Version 1.1.0”, 2021. https://nsgreg.nga.mil/doc/view?i=5421