VECHASH

Description

VECHASH computes a hash number that represents an entire vector segment. This hash number is used as a checksum for software testing.

Parameters

vechash(file, dbvs, hashopt)

Name	Type	Caption	Length	Value range
FILE *	str	Input file name	1 -
DBVS *	List[int]	Input vector segment	1 - 48
HASHOPT	str	Vector hash options	0 - 64	Default: ALL

* Required parameter

Parameter descriptions

FILE

Specifies the name of the GDB-supported file containing the vector segment for which the hash number will be computed.

DBVS

Specifies the input vector segment(s) to be processed.

HASHOPT

Specifies the data types from the vector layer to be included when computing the hash value. Multiple options may be specified to compute a joint hashing value; for example, HASHOPT = SCHEMA ATTRIBUTES.

Valid options include:

VERTICES: hash value is based on (X,Y,Z) vertices
ATTRIBUTES: hash value is based on field values
RST: hash value is based on a Representation Style Table
SCHEMA: hash value is based on specified field names/types
PROJ: hash value is based on projection information
ALL: hash value is based on all of the above; this is the default value
SCHEMA ATTRIBUTES: computes hash values for multiple listed types

Return Value

Returns: Image Statistics

Type: PCI_FLOAT

Parameter: imstat

Upon completion, VECHASH returns hash values for each of the vector segments sampled. This value is always a number between 0 and 32767.

Details

VECHASH computes a hash value for a vector segment in a GDB-supported file. This function is primarily used for the construction of test procedures.

Example

Compute and display the hash values for each of the vector segments in irvine.pix.

from pci.vechash import vechash

file = "irvine.pix"	    # File containing the vector data
dbvs = [25,26]	    # Vector segments to process
hashopt = ""	    # Default is "ALL"
hashcode = []

hashcode = vechash(file,dbvs,hashopt)
print(hashcode)

Environments	PYTHON :: EASI
Quick links	Description :: Parameters :: Parameter descriptions :: Return Value :: Details :: Example :: Related