Define Shapefile Projection with Shapely/Fiona

Question

I am writing a fairly straight forward script of converting GeoJSON data into a shapefile using Shapely and Fiona. My script works but I cannot figure out how to define the CS in the script.

def GeoJSONToFC(shpname,USGSurl):
    import urllib2
    import json
    from shapely.geometry import Point, mapping
    from fiona import collection
    from fiona.crs import from_epsg
    crs = from_epsg(4326)
    schema = {'geometry': 'Point', 'properties': { 'Place': 'str', 'Magnitude': 'str' }}
    with collection(shpname, "w", crs, "ESRI Shapefile", schema) as output:
        url = USGSurl
        weburl = urllib2.urlopen(url)
        if weburl.getcode() == 200:
            data = json.loads(weburl.read())
        for i in data["features"]:
            mag, place = i["properties"]["mag"],i["properties"]["place"]
            x,y = float(i["geometry"]["coordinates"][0]),float(i["geometry"]["coordinates"][1])
            point = Point(x,y)
            output.write({'properties':{'Place': place, 'Magnitude': mag},
            'geometry': mapping(point)})

shpname = "C:\Users\Ralph\Desktop\quakes.shp"
url = "http://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/significant_month.geojson"
GeoJSONToFC(shpname,url)

the crs variable contains the 4326 CS or WGS 1984. the error occurs on line 9 when I insert the crs variable containing the coordinate system into the collection.

Traceback (most recent call last):
  File "C:\Users\Ralph\Desktop\GeoJSONToShapefile.py", line 23, in <module>
    GeoJSONToFC(shpname,url)
  File "C:\Users\Ralph\Desktop\GeoJSONToShapefile.py", line 9, in GeoJSONToFC
    with collection(shpname, "w", crs, "ESRI Shapefile", schema) as output:
  File "C:\Python27\ArcGIS10.1\lib\site-packages\fiona\__init__.py", line 180, in open
    this_schema = schema.copy()
AttributeError: 'str' object has no attribute 'copy'

the script runs fine when I remove the crs variable but the shapefile has no projection

I have seen this post Using Fiona to write a new shapefile from scratch where the answer to defining a CS is

with fiona.open(shapeout, 'w',crs=from_epsg(3857),driver='ESRI Shapefile', schema=yourschema) as output:

I have tried this method and it gives me the exact same error as above. I also checked out the doc pages on fiona to no avail http://toblerity.org/fiona/fiona.html#module-fiona.crs

Answer 1

You are following a red herring, since the issue has nothing to do with a projection, but all to do with the positional arguments of collection (or type help(collection) from an interactive Python shell).

The positional order of arguments should be:

collection(shpname, "w", "ESRI Shapefile", schema, crs)

You can avoid these issues with keyword arguments like:

collection(shpname, "w", crs=crs, driver="ESRI Shapefile", schema=schema)