CImage:GetImageScaleXy CImage:GetWcsType

CImage:GetWcsProj


The GetWcsProj method returns an integer code for the world coordinate system ("WCS") projection used by the image.

Syntax

nWcsProj = CImage:GetWcsProj()

bullet.gif    If a WCS exists, then nWcsProj is returned as nWcsProj in the table below.

bullet.gif    If no WCS exists, then -1 is returned.

Remarks

The mathematical relationship between pixel location and world coordinates is known as the world coordinate projection. The projection type is represented in the FITS header using the CTYPEn keyword, where n refers to the axis dimension. Equatorial calibration usually employs the "Tangent Plane (gnomonic)" projection with CTYPEn Code = TAN. In the FITS header, this equatorial projection for right ascension (axis 1) and declination (axis 2) appears as CTYPE1 = 'RA---TAN' and CTYPE2 = 'DEC--TAN'.

Mira supports the types of WCS projection listed in the table below. The projection type nWcsProj is returned by the present method. The CTYPEn Code is listed in FITS header as the string value of the CTYPEn keyword. The Description is reported by the List WCS Keywords menu command of the Mira user interface.

nWcsProj

CTYPEn Code

Description

-1

 

Pixel WCS (default, no WCS)

0

LIN

Linear projection

1

AZP

Zenithal / Azimuthal Perspective

2

TAN

Tangent Plane (gnomonic)

3

SIN

Orthographic / synthesis

4

STG

Stereographic

5

ARC

Zenithal / azimuthal equidistant

6

ZPN

Zenithal / azimuthal Polymomial

7

ZEA

Zenithal / azimuthal Equal Area

8

AIR

Airy

9

CYP

Cylindrical Perspective

10

CAR

Cartesian

11

MER

Mercator

12

CEA

Cylindrical Equal Area

13

COP

Conic Perspective(COP)

14

COD

Conic equidistant

15

COE

Conic Equal Area

16

COO

Conic Orthomorphic

17

BON

Bonne

18

PCO

Polyconic

19

GLS

Sanson - Flamsteed(Global Sinusoidal)

20

PAR

Parabolic

21

AIT

Hammer - Aitoff

22

MOL

Mollweide

23

CSC

COBE quadrilateralized Spherical Cube

24

QSC

Quadrilateralized Spherical Cube

25

TSC

Tangential Spherical Cube

26

NCP

Special case of Orthographic / synthesis

27

DSS

Digitized Sky Survey plate solution

28

PLT

Plate fit polynomials(SAO)

29

TNX

Tangent Plane (gnomonic, NOAO with corrections)

Related Topics

CImage class

GetWcsType

WcsIsEq

WcsToXy

WcsStrToXy

Image Coordinate System

Subpixel Coordinate Definition

World Coordinate System


Mira Pro x64 Script User's Guide, v.8.73 Copyright Ⓒ 2024 Mirametrics, Inc. All Rights Reserved.