CImage:DistanceWcsStr
The DistanceWcsStr method calculates the distance in WCS units between 2 image points measured in world coordinates and returns the result as a string. The related Distance method computes the Distance for pixel coordinates.
sDistance = CImage:DistanceWcsStr( x1, y1, x2, y2) |
wherex1, y1, x2, y2 are world coordinate values and may be expressed as numbers or strings.
On success, this method returns the distance as a string.
On failure, this method returns nil
The DistanceWcsStr method returns a distance in world coordinate units as a string. Also see the related DistanceWcs method that returns the world coordinate calibrated distance as a number.
Assume an image is displayed and attached to a CImageView named V. The following script fragment measures the Distance between between two points (x1,y1) and (x2,y2) when the coordinates are in distance units (pixels, mm, microns, etc.):
I = V:GetImage() |
-- load the image from a |
x1 = 442.5 ; y1 = 220.44 |
-- point 1 |
x2 = 1.554 ; y2 = 20.552 |
-- point 2 |
sD = I:DistanceWcsStr(x1,y1,x2,y2) |
-- make the measurement, returns a string |
Alternatively, the following example supposes an astronomical image with an equatorial calibration and that the points are expressed in angular units:
V:GetImage() |
-- load the image from a |
x1 = "05:42:15.52" ; y1 = "20:40:12.5" |
-- point 1 |
x2 = "05:42:44.12" ; y2 = "20:42:42.1" |
-- point 2 |
sD = I:DistanceWcsStr(x1,y1,x2,y2) |
-- make the measurement, returns a string |
CImage, Distance, DistanceWcs, Image Coordinate System, Subpixel Coordinate Definition