Made pyproj an optional dependency. Coordinate conversion is disabled…

… if not present.

docs/whatsnew.rst

@@ -15,6 +15,10 @@ Improvements
 * Also read units from quantities other than VarDens (e.g. EnDens and
   AcDens)
 
+* Package `pyproj` is not an optional dependency. Coordinate
+  conversion is disabled if `pyproj` is not installed. Instead a
+  warning is given in that situation.
+
 New functions/methods
 ^^^^^^^^^^^^^^^^^^^^^
 

oceanwaves/oceanwaves.py

@@ -1,16 +1,18 @@
 from __future__ import absolute_import
 
 import copy
-import pyproj
 import logging
 import numpy as np
 import xarray as xr
 import scipy.integrate
 import scipy.interpolate
 from collections import OrderedDict
 
-from xarray.core.coordinates import DatasetCoordinates
-from xarray.core.dataset import DataVariables
+try:
+    import pyproj
+    HAS_PYPROJ = True
+except ImportError:
+    HAS_PYPROJ = False
 
 from oceanwaves.utils import *
 from oceanwaves.units import simplify
@@ -1088,15 +1090,19 @@ def convert_coordinates(self, crs):
         if self.has_dimension('location'):
 
             if crs is not None:
-                k = self._key_lookup('_location')
-                p1 = pyproj.Proj(init=crs)
-                p2 = pyproj.Proj(proj='latlong', datum='WGS84')
-                x = self._variables['%s_x' % k].values
-                y = self._variables['%s_y' % k].values
-                lat, lon = pyproj.transform(p1, p2, x, y)
-                self.variables['%s_lat' % k].values = lat
-                self.variables['%s_lon' % k].values = lon
-                self.attrs['_crs'] = crs
+                if not HAS_PYPROJ:
+                    logger.warn('Package "pyproj" is not installed, cannot '
+                                'apply coordinate reference system.')
+                else:
+                    k = self._key_lookup('_location')
+                    p1 = pyproj.Proj(init=crs)
+                    p2 = pyproj.Proj(proj='latlong', datum='WGS84')
+                    x = self._variables['%s_x' % k].values
+                    y = self._variables['%s_y' % k].values
+                    lat, lon = pyproj.transform(p1, p2, x, y)
+                    self.variables['%s_lat' % k].values = lat
+                    self.variables['%s_lon' % k].values = lon
+                    self.attrs['_crs'] = crs
 
 
     def __getitem__(self, key):

oceanwaves/swan.py

@@ -4,14 +4,19 @@
 import re
 import glob
 import json
-import pyproj
 import logging
 import xarray as xr
 import numpy as np
 import pandas as pd
 from datetime import datetime
 from collections import OrderedDict
 
+try:
+    import pyproj
+    HAS_PYPROJ = True
+except ImportError:
+    HAS_PYPROJ = False
+
 import oceanwaves.oceanwaves
 
 
@@ -412,7 +417,11 @@ def write_locations(self, latlon=False):
 
             crs = self._get_attr('_crs')
             if crs is not None:
-                latlon = pyproj.Proj(init=crs).is_latlong()
+                if not HAS_PYPROJ:
+                    logger.warn('Package "pyproj" is not installed, cannot '
+                                'apply coordinate reference system.')
+                else:
+                    latlon = pyproj.Proj(init=crs).is_latlong()
 
             if latlon:
                 self.fp.write('LONLAT\n')

setup.py

@@ -37,7 +37,6 @@
     python_requires='>=2.7, <4',
     install_requires=[
         'docopt',
-        'pyproj',
         'xarray',
         'scipy',
         'numpy',