[GIS] Save Start/End Points in another shapefile using Shapely

fionashapely

I'm trying to get the start/End points of a Shapefile which geometry type is lines, using Shapely.

Here's what I tried : 

import geopandas
from shapely.geometry import *
import fiona

schema = {
'geometry': 'Point',
'properties': {'id': 'int'},
}
for line in fiona.open("./Shapefiles/tl.shp"):
# Write a new Shapefile
with fiona.open('./Outputs/result.shp', 'w', 'ESRI Shapefile', schema) as c:
    startEndPoints = Point(line['geometry']['coordinates'][0]), Point(line['geometry']['coordinates'][-1])
    c.write({
        'geometry': mapping(startEndPoints),
        'properties': {'id': 'int'},
    })

After running the script I got this error : 

Traceback (most recent call last):
File "C:/Users/User/Documents/Scripts/startEndPoints.py", line 15, in <module>
'geometry': mapping(startEndPoints),
File "C:\Program Files (x86)\Python27\lib\site-packages\shapely\geometry\geo.py", line 75, in mapping
return ob.__geo_interface__
AttributeError: 'tuple' object has no attribute '__geo_interface__'

Process finished with exit code 1

Any idea on what the problem is? Am I missing something?

By the way if I just put :

from shapely.geometry import Point
import fiona
for line in fiona.open("./Shapefiles/tl.shp"):
print Point(line['geometry']['coordinates'][0]), Point(line['geometry']['coordinates'][-1])

I get the results :

POINT (-122.4136252231131 37.77444689220926) POINT (-122.4123122222042 37.77339989262978)
POINT (-122.4166172233352 37.77561789207194) POINT (-122.4168352231301 37.77544489272536)
POINT (-122.4254669503756 37.80586514841474) POINT (-122.4253414477887 37.80523738337594)
POINT (-122.4120802227251 37.77329289282841) POINT (-122.4116882221326 37.77360289269223)
POINT (-122.403928221227 37.76968489249516) POINT (-122.4038392206211 37.7686898923368)
POINT (-122.4034062214653 37.77768889337421) POINT (-122.402952221485 37.77804389367528)
POINT (-122.4083362215629 37.77378789309976) POINT (-122.4073822219715 37.77454389279772)
POINT (-122.3988001599508 37.77642529193749) POINT (-122.4004541112463 37.77511695816931)
POINT (-122.3995072203815 37.7666648926454) POINT (-122.3991442197841 37.76637989275558)
POINT (-122.3954705174111 37.75052611064412) POINT (-122.3954953388096 37.75079277249778)
POINT (-122.4096502215665 37.77017689206735) POINT (-122.4086142215983 37.76934889254507)
POINT (-122.40679422218 37.77255089251806) POINT (-122.4065396542004 37.77275206969875)
POINT (-122.3911729658918 37.76952536147485) POINT (-122.3910978699473 37.76875434317915)
POINT (-122.408514985576 37.76433570878993) POINT (-122.4084132127141 37.76323936432929)
....
Process finished with exit code 0

My only problem is saving these endpoints in another shapefile. Any ideas?

I managed to solve the problem with a workaround actually. What I did is save the startPoints and endPoints each in a different shapefile.
Here's my code : 

from shapely.geometry import *
import fiona

schema = {'geometry': 'Point' }
with fiona.open("./TLShapefile/TimeLimits.shp") as input:
    input.schema['geometry'] = "Point"
    # write the startPoint shapefile
    with fiona.open('./Outputs/endPoints.shp', 'w', 'ESRI Shapefile', input.schema.copy(), input.crs) as output:
    for line in input:
        geom = shape(line['geometry'])
        # Write a new Shapefile for the startPoints, do the same thing for endPoints afterwards
        startPoints = Point(line['geometry']['coordinates'][0])
        #endPoints = Point(line['geometry']['coordinates'][-1]) #For the end points
        elem['geometry'] = mapping(startPoints)
        #elem['geometry'] = mapping(endPoints) #For the end points
        output.write(elem)

Now I have seperate shapefiles for the start points and the end points.
Although my main goal is to get one shapefile with the startpoints and endpoints all together.

I have updated my code based on Gene's answer, using Shapely : 

from shapely.geometry import *
import fiona

schema = {
'geometry': 'Point',
'properties': { 'AGENCY': 'str',
                'CONFLICT' :'int',
                'CREATED_DA' :'str',
                'CREATED_US' :'str',
                'CREATED__1' :'str',
                'CREATED__2' :'str',
                'DAYS' :'str',
                'EDITOR' :'str',
                'ENACTED' :'str'
with fiona.open("tl.shp") as input:
    # write the startPoint shapefile
    with fiona.open('./Outputs/startEndPoints.shp', 'w', 'ESRI Shapefile', schema, input.crs) as output:
    for line in input:
        startEndPoints = MultiPoint([line['geometry']['coordinates'][0],  line['geometry']['coordinates'][-1]])
        for point in startEndPoints:
        output.write({'geometry': mapping(point), 'properties': {
                'AGENCY': 'str',
                'CONFLICT' :'int',
                'CREATED_DA' :'str',
                'CREATED_US' :'str',
                'CREATED__1' :'str',
                'CREATED__2' :'str',
                'DAYS' :'str',
                'EDITOR' :'str',
                'ENACTED' :'str'}})

When I run the script now I get this : 

Process finished with exit code -1073741819 (0xC0000005)

Best Answer

Why import geopandas if you don't use it ? (GeoPandas = Pandas + Fiona + Shapely)

1) Following the suggestion of bugmenot123

The schema for a MultiLineString

schema = {
'geometry': 'MultiPoint',
'properties': {'id': 'int'},
 }

And

with fiona.open("lines.shp") as inp:
    with fiona.open('result.shp', 'w', 'ESRI Shapefile', schema) as out:
       for line in inp:
           startEndPoints = MultiPoint([line['geometry']['coordinates'][0],  line['geometry']['coordinates'][-1]])
           out.write({'geometry': mapping(startEndPoints),'properties': {'id': 1}})

2) But a shapefile has no MultiPoint schema geometries: a shapefile that indicates Point in its schema may yield either Point or MultiPoint features (simple list of Point).

Therefore:

schema = {
'geometry': 'Point',
'properties': {'id': 'int'},
 }
with fiona.open("lines.shp") as inp:
with fiona.open('result2.shp', 'w', 'ESRI Shapefile', schema2) as out:
    for line in inp:
        startEndPoints = MultiPoint([line['geometry']['coordinates'][0],  line['geometry']['coordinates'][-1]])
        for point in startEndPoints: 
           out.write({'geometry': mapping(point),'properties': {'id': 1}})

3) Now, if you want to use GeoPandas only 

import geopandas as gpd
from geopandas.geoseries import Point
lines = gpd.GeoDataFrame.from_file("lines.shp")
startpts = gpd.GeoSeries([Point(list(pt['geometry'].coords)[0]) for i,pt in lines.iterrows()])
endpts = gpd.GeoSeries([Point(list(pt['geometry'].coords)[-1]) for i,pt in lines.iterrows()])
points = startpts.append(endpts)
result = gpd.GeoDataFrame(points,columns=['geometry'])
# add a field
result['id']= result.index
# save the resulting shapefile
result.to_file("res_geopandas.shp")

New

 # columns of the GeoDataframe line
 print lines.columns.values
 [u'AFFLEUR' u'IDENT' u'NATURE' 'geometry']
 print lines['IDENT']
 0    3560025
 1    3560023
 2    3560024
 Name: IDENT, dtype: int64

Suppose that I want to add the IDENT column to the results

  # create a GeoDataFrame with the startpts GeoSerie
  dfstartpts = gpd.GeoDataFrame(startpts,columns=['geometry'])
  # add a column and copy the values of IDENT
  dfstartpts['ident'] = lines['IDENT']
  # same for the endpoints
  dfendpts = gpd.GeoDataFrame(endpts,columns=['geometry'])
  dfsendpts['ident'] = lines['IDENT']
  # "merge" the dataframes
  result = dfstartpts.append(dfendpts)
  print result.columns.values
  ['geometry' 'ident']
  print result['ident']
  0    3560025
  1    3560023
  2    3560024
  0    3560025
  1    3560023
  2    3560024
  Name: ident, dtype: int64
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