How to use the fiona.crs.from_string function in fiona

def test_towgs84():
    """+towgs84 is preserved"""
    proj4 = ('+proj=lcc +lat_1=49 +lat_2=46 +lat_0=47.5 '
             '+lon_0=13.33333333333333 +x_0=400000 +y_0=400000 +ellps=bessel '
             '+towgs84=577.326,90.129,463.919,5.137,1.474,5.297,2.4232 '
             '+units=m +wktext +no_defs')
    assert 'towgs84' in crs.from_string(proj4)

def test_wktext():
    """Test +wktext parameter is preserved."""
    proj4 = ('+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 '
             '+x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext '
             '+no_defs')
    assert 'wktext' in crs.from_string(proj4)

print(len(list(c)))
except:
    print(c.closed)
    raise

###############################################################################
c = fiona.open('/gdata/GSHHS_c.shp')
c.driver
###############################################################################
c.crs
###############################################################################
from fiona.crs import to_string
to_string(c.crs)
###############################################################################
from fiona.crs import from_string
from_string(
    "+datum=WGS84 +ellps=WGS84 +no_defs +proj=longlat")
###############################################################################
from fiona.crs import from_epsg
from_epsg(3857)
###############################################################################
len(c)
###############################################################################
c.bounds

def pick_projection(project):
    use_proj, out_crs = None, None

    if project.lower() in ('local', 'utm'):
        use_proj = project.lower()

    elif os.path.exists(project):
        # Is a file
        with open(project) as f:
            out_crs = fiona.crs.from_string(f.read())

    elif project[:5].lower() == 'epsg:':
        # Is an epsg code
        _, epsg = project.split(':')
        out_crs = fiona.crs.from_epsg(int(epsg))

    else:
        # Assume it's a proj4 string.
        # fiona.crs.from_string returns {} if it isn't.
        out_crs = fiona.crs.from_string(project)

    return use_proj, out_crs

if epsg == 4326:
            value = WGS84().value

        # Add a special check for init keys in value dictionary.
        if value is not None:
            if 'init' in value and list(value.values())[0].startswith('epsg'):
                epsg = int(list(value.values())[0].split(':')[1])
                value = None

        if value is None:
            if proj4 is not None:
                value = from_string(proj4)
            elif epsg is not None:
                sr = SpatialReference()
                sr.ImportFromEPSG(epsg)
                value = from_string(sr.ExportToProj4())
            else:
                msg = 'A value dictionary, PROJ.4 string, or EPSG code is required.'
                raise ValueError(msg)
        else:
            # Remove unicode to avoid strange issues with proj and fiona.
            for k, v in value.items():
                if isinstance(v, six.string_types):
                    value[k] = str(v)
                else:
                    try:
                        value[k] = v.tolist()
                    # this may be a numpy arr that needs conversion
                    except AttributeError:
                        continue

        sr = SpatialReference()

project = project or 'default'

    if isinstance(project, dict):
        return project

    elif isinstance(project, string_types):
        if project.lower() == 'file':
            out_crs = file_crs if file_crs is not None else 'file'

        # Is an epsg code
        elif project.lower()[:5] == 'epsg:':
            out_crs = fiona.crs.from_epsg(int(project.split(':')[1]))

        elif project.lower() in METHODS:
            try:
                out_crs = fiona.crs.from_string(generateproj4(project, bounds, file_crs))

            except ValueError:
                return project

        # Is a file
        elif os.path.exists(project):
            with open(project) as f:
                out_crs = fiona.crs.from_string(f.read())

        else:
            # Assume it's a proj4 string.
            # fiona.crs.from_string returns {} if it isn't.
            out_crs = fiona.crs.from_string(project)

    return out_crs

elif project.lower() in METHODS:
            try:
                out_crs = fiona.crs.from_string(generateproj4(project, bounds, file_crs))

            except ValueError:
                return project

        # Is a file
        elif os.path.exists(project):
            with open(project) as f:
                out_crs = fiona.crs.from_string(f.read())

        else:
            # Assume it's a proj4 string.
            # fiona.crs.from_string returns {} if it isn't.
            out_crs = fiona.crs.from_string(project)

    return out_crs

def to_geopandas(raster, **kwargs):
    """
    Convert GeoRaster to GeoPandas DataFrame, which can be easily exported to other types of files
    and used to do other types of operations.
    The DataFrame has the geometry (Polygon), row, col, value, x, and y values for each cell
    Usage:
        df = gr.to_geopandas(raster)
    """
    df = to_pandas(raster, **kwargs)
    df['geometry'] = df.apply(squares, georaster=raster, axis=1)
    df = gp.GeoDataFrame(df, crs=from_string(raster.projection.ExportToProj4()))
    return df

raise ValueError(msg)
        else:
            # Remove unicode to avoid strange issues with proj and fiona.
            for k, v in value.items():
                if isinstance(v, six.string_types):
                    value[k] = str(v)
                else:
                    try:
                        value[k] = v.tolist()
                    # this may be a numpy arr that needs conversion
                    except AttributeError:
                        continue

        sr = SpatialReference()
        sr.ImportFromProj4(to_string(value))
        self.value = from_string(sr.ExportToProj4())

        try:
            assert self.value != {}
        except AssertionError:
            msg = 'Empty CRS: The conversion to PROJ.4 may have failed. The CRS value is: {0}'.format(value)
            raise ValueError(msg)