__init__ (self,
egm_pgm,
crop=None,
datum=None,
kind=3,
name='',
smooth=0)
(Constructor)
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New GeoidPGM interpolator.
- Arguments:
egm_pgm - An EGM geoid dataset file name
(egm*.pgm ).
crop - Optional box to crop egm_pgm , a 4-tuple
(south, west, north, east ) or 2-tuple ((south,
west), (north, east) ), in degrees90 lat- and
degrees180 longitudes or a 2-tuple (LatLonSW,
LatLonNE ) of LatLon instances.
datum - Optional grid datum (Datum, Ellipsoid, Ellipsoid2 or a_f2Tuple), default WGS84 .
kind - scipy.interpolate order (int ), use 1..5
for RectBivariateSpline, -2 for interp2d linear, -3 for interp2d
cubic or -5 for interp2d quintic .
name - Optional geoid name (str ).
smooth - Smoothing factor for RectBivariateSpline only (int ).
- Raises:
GeoidError - EGM dataset egm_pgm issue or invalid
crop , kind or
smooth .
ImportError - Package numpy or scipy not found or not
installed.
LenError - EGM dataset egm_pgm axis mismatch.
SciPyError - A RectBivariateSpline or inter2d issue.
SciPyWarning - A RectBivariateSpline or inter2d warning
as exception.
TypeError - Invalid datum .
- Overrides:
object.__init__
Notes:
-
scipy.interpolate.interp2d has been
DEPRECATED , specify kind=1..5 for
scipy.interpolate.RectBivariateSpline .
-
The GeographicLib egm*.pgm file sizes are based on a
2-byte
int height converted to 8-byte dtype
float64 for scipy interpolators. Therefore,
internal memory usage is 4 times the egm*.pgm file
size and may exceed the available memory, especially with 32-bit
Python. To reduce memory usage, set keyword argument
crop to the region of interest. For example
crop=(20, -125, 50, -65) covers the conterminous US (CONUS), less than 3% of the
entire egm2008-1.pgm dataset.
See Also:
Class GeoidKarney and function egmGeoidHeights.
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