Function process_crs

hvplot/util.py:339–412

Parses cartopy CRS definitions defined in one of a few formats: 1. EPSG codes: Defined as string of the form "EPSG: {code}" or an integer 2. proj.4 string: Defined as string of the form "{proj.4 string}" 3. cartopy.crs.CRS instance 3. pyproj.Proj or pyproj.CRS instanc

(crs)

def process_crs(crs):
    """
    Parses cartopy CRS definitions defined in one of a few formats:

      1. EPSG codes:   Defined as string of the form "EPSG: {code}" or an integer
      2. proj.4 string: Defined as string of the form "{proj.4 string}"
      3. cartopy.crs.CRS instance
      3. pyproj.Proj or pyproj.CRS instance
      4. WKT string:    Defined as string of the form "{WKT string}"
      5. None defaults to crs.PlateCaree
    """
    missing = []
    try:
        import cartopy.crs as ccrs
    except ImportError:
        missing.append('cartopy')
    try:
        import geoviews as gv  # noqa
    except ImportError:
        missing.append('geoviews')
    try:
        import pyproj
    except ImportError:
        missing.append('pyproj')
    if missing:
        raise ImportError(f'Geographic projection support requires: {", ".join(missing)}.')

    if crs is None:
        return ccrs.PlateCarree()
    elif isinstance(crs, ccrs.CRS):
        return crs
    elif isinstance(crs, str):
        all_crs = [
            proj
            for proj in dir(ccrs)
            if callable(getattr(ccrs, proj))
            and proj not in ['ABCMeta', 'CRS']
            and proj[0].isupper()
            or proj == 'GOOGLE_MERCATOR'
        ]
        if crs in all_crs and crs != 'GOOGLE_MERCATOR':
            return getattr(ccrs, crs)()
        elif crs == 'GOOGLE_MERCATOR':
            return getattr(ccrs, crs)
    elif isinstance(crs, pyproj.CRS):
        crs = crs.to_wkt()

    errors = []
    if isinstance(crs, (str, int, pyproj.Proj)):
        wkt = crs
        if isinstance(crs, (str, int)):  # epsg codes
            try:
                wkt = pyproj.CRS.from_epsg(crs).to_wkt()
            except Exception as e:
                errors.append(e)
        try:
            return proj_to_cartopy(wkt)  # should be all proj4 or wkt strings
        except Exception as e: