Merge pull request #1 from CSU-Radarmet/master

Merging nguy edits

Author: tjlang

README.md

@@ -7,15 +7,15 @@ including Brenda Dolan, Brody Fuchs, Kyle Wiens, Rob Cifelli, Larry Carey, Timot
 and others.
 
 Currently, fuzzy-logic-based hydrometeor identification, blended rainfall,
-DSD retrievals, and liquid/ice mass calculations are supported. There is also an 
+DSD retrievals, and liquid/ice mass calculations are supported. There is also an
 algorithm that uses a finite impulse response (FIR) filter to process differential phase
 and calculate specific differential phase.
 Finally, there are some tools to do rudimentary QC on the data.
 
 These are supplied as standalone functions that take polarimetric radar data
 as arguments. Scalars and arrays are supported as function inputs. The main exception
-is `csu_kdp.calc_kdp_bringi()` which requires individual rays, sweeps, or volumes of 
-radar data. 
+is `csu_kdp.calc_kdp_bringi()` which requires individual rays, sweeps, or volumes of
+radar data.
 
 CSU_RadarTools Installation
 ---------------------------
@@ -36,10 +36,10 @@ routines have been substantially altered.</b>
 
 To access, use the following in your analysis code:
 ```
-from csu_radartools import (csu_fhc, csu_liquid_ice_mass, csu_blended_rain, csu_dsd, 
-                            csu_kdp, csu_misc)
+from csu_radartools import (csu_fhc, csu_liquid_ice_mass, csu_blended_rain, csu_dsd,
+                            csu_kdp, csu_misc, fundamentals)
 ```
 
-For help information do help on individual modules. There is also a demonstration IPython notebook in the notebooks directory that covers all the modules. 
+For help information do help on individual modules. There is also a demonstration IPython notebook in the notebooks directory that covers all the modules.
 
 CSU_RadarTools is known to work under Python 2.7 and 3.4. Other Python versions are untested.

csu_radartools/common.py

@@ -0,0 +1,126 @@
+# -*- coding: utf-8 -*-
+"""
+common sub-module of csu_radartools
+
+Contains commonly used functions.
+
+Nick Guy 10 May 2016
+"""
+import numpy as np
+
+##############
+##  Arrays  ##
+##############
+
+
+def _check_for_array(dz, zdr, kdp):
+    len_flag = hasattr(dz, '__len__')
+    if not len_flag:
+        dz = np.array([dz])
+        kdp = np.array([kdp])
+        zdr = np.array([zdr])
+    return dz, zdr, kdp, len_flag
+
+########################
+##  Unit Conversions  ##
+########################
+
+
+def dbz2z(dbz):
+    """
+    Convert from log [dBZ] to linear Z [mm^6 m^−3] units.
+
+    Parameters
+    ----------
+    dbz : float or array
+        logarithmic reflectivity value
+    """
+    return 10.**(np.asarray(dbz)/10.)
+
+
+def linearize(dbz):
+    return dbz2z(dbz)
+
+
+def z2dbz(zlin):
+    """
+    Convert from linear Z [mm^6 m^−3] to log [dBZ] units.
+
+    Parameters
+    ----------
+    zlin : float or array
+        linear reflectivity units
+    """
+    return 10. * np.log10(np.asarray(zlin))
+
+
+def si2kmh(si):
+    """
+    Convert from SI [m/s] wind units to km/h.
+
+    Parameters
+    ----------
+    si : float or array
+        Wind in SI units (m/s)
+    """
+    return np.asarray(si) * 3600. / 1000.
+
+
+def si2mph(si):
+    """
+    Convert from SI wind units to miles/h [mph].
+
+    Parameters
+    ----------
+    si: float or array
+        Wind in SI units (m/s)
+    """
+    return np.asarray(si) * 0.62137 / 1000. * 3600.
+
+
+def si2kts(si):
+    """
+    Convert from SI wind units to knots [kt].
+
+    Parameters
+    ----------
+    si: float or array
+        Wind in SI units (m/s)
+    """
+    return np.asarray(si) * 0.51
+
+
+def kmh2si(kmh):
+    """
+    Convert from km/h to SI wind units [m/s].
+
+    Parameters
+    ----------
+    kmh: float or array
+        Wind in km/hr
+    """
+    return np.asarray(kmh) * 1000. / 3600.
+
+
+def mph2si(mph):
+    """
+    Convert from miles/h to SI wind units [m/s].
+
+    Parameters
+    ----------
+    mph: float or array
+        Wind in miles per hour
+    """
+    return np.asarray(mph) * 1000. / (0.62137 * 3600.)
+
+
+def kts2si(kts):
+    """
+    Convert from knots to SI wind units [m/s].
+
+    Parameters
+    ----------
+    kts: float or array
+        Wind in knots
+    """
+    return np.asarray(kts) / 0.51