ComputePixelScale

class lsst.pipe.tasks.functors.ComputePixelScale(colCD_1_1, colCD_1_2, colCD_2_1, colCD_2_2, **kwargs)

Bases: LocalWcs

Compute the local pixel scale from the stored CDMatrix.

Attributes Summary

columns	Columns required to perform calculation.
name
noDup	Do not explode by band if used on object table.
shortname	Short name of functor (suitable for column name/dict key).

Methods Summary

__call__(data[, dropna])	Call self as a function.
computeDeltaRaDec(x, y, cd11, cd12, cd21, cd22)	Compute the distance on the sphere from x2, y1 to x1, y1.
computeSkySeparation(ra1, dec1, ra2, dec2)	Compute the local pixel scale conversion.
difference(data1, data2, **kwargs)	Computes difference between functor called on two different DataFrame/Handle objects.
fail(df)
getSkySeparationFromPixel(x1, y1, x2, y2, ...)	Compute the distance on the sphere from x2, y1 to x1, y1.
multilevelColumns(data[, columnIndex, ...])	Returns columns needed by functor from multilevel dataset.
pixelScaleArcseconds(cd11, cd12, cd21, cd22)	Compute the local pixel to scale conversion in arcseconds.

Attributes Documentation

columns

name = 'PixelScale'

noDup

Do not explode by band if used on object table.

shortname

Short name of functor (suitable for column name/dict key).

Methods Documentation

__call__(data, dropna=False)

Call self as a function.

computeDeltaRaDec(x, y, cd11, cd12, cd21, cd22)

Compute the distance on the sphere from x2, y1 to x1, y1.

Parameters:

xSeries

X pixel coordinate.

ySeries

Y pixel coordinate.

cd11Series

[1, 1] element of the local Wcs affine transform.

cd11Series

[1, 1] element of the local Wcs affine transform.

cd12Series

[1, 2] element of the local Wcs affine transform.

cd21Series

[2, 1] element of the local Wcs affine transform.

cd22Series

[2, 2] element of the local Wcs affine transform.

Returns:

raDecTupletuple

RA and dec conversion of x and y given the local Wcs. Returned units are in radians.

computeSkySeparation(ra1, dec1, ra2, dec2)

Compute the local pixel scale conversion.

Parameters:

ra1Series

Ra of the first coordinate in radians.

dec1Series

Dec of the first coordinate in radians.

ra2Series

Ra of the second coordinate in radians.

dec2Series

Dec of the second coordinate in radians.

Returns:

distSeries

Distance on the sphere in radians.

difference(data1, data2, **kwargs)

Computes difference between functor called on two different DataFrame/Handle objects.

fail(df)

getSkySeparationFromPixel(x1, y1, x2, y2, cd11, cd12, cd21, cd22)

Compute the distance on the sphere from x2, y1 to x1, y1.

Parameters:

x1Series

X pixel coordinate.

y1Series

Y pixel coordinate.

x2Series

X pixel coordinate.

y2Series

Y pixel coordinate.

cd11Series

[1, 1] element of the local Wcs affine transform.

cd11Series

[1, 1] element of the local Wcs affine transform.

cd12Series

[1, 2] element of the local Wcs affine transform.

cd21Series

[2, 1] element of the local Wcs affine transform.

cd22Series

[2, 2] element of the local Wcs affine transform.

Returns:

DistanceSeries

Arcseconds per pixel at the location of the local WC.

multilevelColumns(data, columnIndex=None, returnTuple=False)

Returns columns needed by functor from multilevel dataset.

To access tables with multilevel column structure, the DeferredDatasetHandle or InMemoryDatasetHandle needs to be passed either a list of tuples or a dictionary.

Parameters:

datavarious

The data as either DeferredDatasetHandle, or InMemoryDatasetHandle.

columnIndex (optional): pandas `~pandas.Index` object

Either passed or read in from DeferredDatasetHandle.

`returnTuple`bool

If true, then return a list of tuples rather than the column dictionary specification. This is set to True by CompositeFunctor in order to be able to combine columns from the various component functors.

pixelScaleArcseconds(cd11, cd12, cd21, cd22)

Compute the local pixel to scale conversion in arcseconds.

Parameters:

cd11Series

[1, 1] element of the local Wcs affine transform in radians.

cd11Series

[1, 1] element of the local Wcs affine transform in radians.

cd12Series

[1, 2] element of the local Wcs affine transform in radians.

cd21Series

[2, 1] element of the local Wcs affine transform in radians.

cd22Series

[2, 2] element of the local Wcs affine transform in radians.

Returns:

pixScaleSeries

Arcseconds per pixel at the location of the local WC.