NMSD
Reputation: 494
Parsing co-ordinate values in a JSON file and extract their corresponding attribute value
I have this JSON in a file:
{
"type": "FeatureCollection",
"generator": "overpass-turbo",
"copyright": "The data included in this document is from www.openstreetmap.org. The data is made available under ODbL.",
"timestamp": "2017-02-23T15:12:02Z",
"features": [
{
"type": "Feature",
"id": "relation/2264913",
"properties": {
"@id": "relation/2264913",
"admin_level": "10",
"boundary": "administrative",
"name": "ABC",
"type": "boundary"
},
"geometry": {
"type": "Polygon",
"coordinates": [
[
[
12.0397449,
51.6438084
],
[
12.0388557,
51.6403582
],
[
12.0413471,
51.640221
],
[
12.0405388,
51.6377118
],
[
12.0423344,
51.6374845
],
[
12.0419595,
51.6343258
],
[
12.0804867,
51.6295502
],
[
12.0698061,
51.6438756
],
[
12.0681545,
51.6437836
],
[
12.0658655,
51.6436203
],
[
12.0632812,
51.6438909
],
[
12.0627055,
51.6442096
],
[
12.063009,
51.6448326
],
[
12.0574821,
51.6445929
],
[
12.0557545,
51.6445538
],
[
12.0519454,
51.6441561
],
[
12.0475772,
51.6440126
],
[
12.0397449,
51.6438084
]
]
]
}
},{
"type": "Feature",
"id": "relation/6249468",
"properties": {
"@id": "relation/6249468",
"landuse": "farmland",
"type": "multipolygon"
},
"geometry": {
"type": "Polygon",
"coordinates": [
[
[
12.0473976,
51.6439141
],
[
12.0505144,
51.6439299
],
[
12.0511152,
51.6439698
],
[
12.0516503,
51.6439931
],
[
12.0523275,
51.6440464
],
[
12.0534621,
51.6441396
],
[
12.053843,
51.6441854
],
[
12.0543982,
51.6442436
],
[
12.0545672,
51.6442727
],
[
12.0553759,
51.6444417
],
[
12.0554563,
51.6444667
],
[
12.055522,
51.6445033
],
[
12.0555596,
51.6445424
],
[
12.0555851,
51.6445981
],
[
12.0556065,
51.6447213
],
[
12.0556333,
51.6448386
],
[
12.0556588,
51.6449244
],
[
12.0557084,
51.6450334
],
[
12.055738,
51.6451124
],
[
12.0558023,
51.6453355
],
[
12.0558868,
51.645531
],
[
12.0561852,
51.645526
],
[
12.0565098,
51.6455568
],
[
12.0570207,
51.6456001
],
[
12.0572956,
51.6456126
],
[
12.0574405,
51.6456276
],
[
12.0575451,
51.6456534
],
[
12.057643,
51.6456966
],
[
12.057706,
51.6457466
],
[
12.0577463,
51.6458015
],
[
12.0577744,
51.6458622
],
[
12.0577905,
51.6459288
],
[
12.0577959,
51.6459962
],
[
12.0577851,
51.6460736
],
[
12.0577382,
51.6461768
],
[
12.057352,
51.6466353
],
[
12.0572889,
51.6467169
],
[
12.0572313,
51.6468076
],
[
12.056904,
51.6475399
],
[
12.0566519,
51.6475282
],
[
12.0563327,
51.6474841
],
[
12.0559586,
51.6473984
],
[
12.0556649,
51.6473202
],
[
12.0555509,
51.6472811
],
[
12.0554449,
51.6472353
],
[
12.0553215,
51.6471962
],
[
12.052414,
51.6465338
],
[
12.0521485,
51.6464814
],
[
12.0518749,
51.6464473
],
[
12.0515061,
51.6464065
],
[
12.0504748,
51.6462933
],
[
12.0499759,
51.6462484
],
[
12.0495588,
51.6462309
],
[
12.049127,
51.6462193
],
[
12.0486402,
51.6461959
],
[
12.048506,
51.646166
],
[
12.0485168,
51.645898
],
[
12.0485597,
51.6457915
],
[
12.0485396,
51.6457349
],
[
12.0484712,
51.645695
],
[
12.0484256,
51.6456351
],
[
12.0484149,
51.6453296
],
[
12.0483988,
51.6450326
],
[
12.0483693,
51.6450109
],
[
12.0482714,
51.6450043
],
[
12.0482767,
51.6456018
],
[
12.0483116,
51.6465022
],
[
12.0483035,
51.6465929
],
[
12.0482807,
51.6466528
],
[
12.0482204,
51.6466936
],
[
12.0481319,
51.6467002
],
[
12.0479904,
51.6466969
],
[
12.0472233,
51.6466503
],
[
12.0469014,
51.6465904
],
[
12.0457454,
51.6462842
],
[
12.0473976,
51.6439141
]
]
]
}
},{
"type": "Feature",
"id": "way/420433184",
"properties": {
"@id": "way/420433184",
"@relations": [
{
"role": "admin_centre",
"rel": "2264913",
"reltags": {
"admin_level": "10",
"boundary": "administrative",
"name": "ABC",
"type": "boundary"
}
}
]
},
"geometry": {
"type": "Point",
"coordinates": [
12.0622848,
51.6370034
]
}
}
]
}
I have loaded the JSON file using Python as shown below:
import json
with open('data.json') as data_file:
data = json.load(data_file)
I need to find the corresponding "@id" attribute for each of the co-ordinates inputs.
Example:
Latitude Longitude Element ID (need to found)
1. 12.0534621 51.6441396 6249468
2. 12.0473976 51.6439141 6249468
3. 12.0622848 51.6370034 420433184
. . .
How do I get the attribute values of the corresponding latitude and longitude? How do you do it iteratively if you have some 100 or more rows of latitude and longitude?
Any help would be really helpful :)
Upvotes: 1
Views: 3213
Answers (1)
Jonathan Portorreal
Reputation: 2836
You could map this function over the list of lat/longs to get a list of all the id's heres the updated code works by considering polygon vs point:
def get_element_id(latitude, longtitude):
"checks each object for lat/long returns objects id or -1 if not found"
# some helper lambda functions
check_coords = lambda arr: [latitude, longtitude] in arr
get_curr_id = lambda obj: obj["properties"]["@id"].split("/")[1]
# since features is an array of 2d arrays
for obj in data["features"]:
obj_type = obj["geometry"]["type"]
curr_arr = obj["geometry"]["coordinates"]
if(obj_type == "Polygon"):
if(any(map(check_coords, curr_arr))):
return get_curr_id(obj)
if(obj_type == "Point"):
if(check_coords([curr_arr]):
return get_curr_id(obj)
# lat/long not found
return -1
print get_element_id(12.0397449, 51.6438084) # prints 2264913
print get_element_id(12.0658655, 51.6436203) # prints 2264913
print get_element_id(12.052414, 51.6465338) # prints 6249468
print get_element_id(12.0622848, 51.6370034) # prints 420433184
Upvotes: 2
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