geo-l1-cairo-multipoint-hull
Map (reference ← swipe → agent)
0:00
I'm putting together the accessibility report for the Metro, and its static maps need to show how far each station's underground box reaches at street level. `cairo_metro_stations.geojson` has each station's street-level entrances. Can you compute the convex hull of each station's entrances and save the result to `cairo_metro_hulls.geojson`, one Polygon per station? Every row must carry `station_name_en` and `station_name_ar`, both non-empty, with the original Arabic strings and diacritics preserved exactly as they appear in the input.
0:00
System info
{
"adapter": "openrouter",
"model": "deepseek/deepseek-v4-flash",
"base_url": "https://openrouter.ai/api/v1"
}
0:02
Let me start by reading the input file to understand its structure.
0:02
Read
/work/cairo_metro_stations.geojson
1 {
2 "type": "FeatureCollection",
3 "name": "cairo_metro_stations",
4 "crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },
5 "features": [
6 { "type": "Feature", "properties": { "station_name_en": "Al-Shohadaa", "station_name_ar": "الشهداء" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.246441, 30.063109 ], [ 31.246778, 30.062428 ], [ 31.246859, 30.063158 ], [ 31.247736, 30.061538 ], [ 31.247931, 30.062636 ] ] } },
7 { "type": "Feature", "properties": { "station_name_en": "Attaba", "station_name_ar": "العتبة" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.246196, 30.051508 ], [ 31.246396, 30.051849 ], [ 31.246716, 30.051944 ], [ 31.246936, 30.052384 ], [ 31.247559, 30.052018 ] ] } },
8 { "type": "Feature", "properties": { "station_name_en": "Cairo University", "station_name_ar": "جامعة القاهرة" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.200216, 30.025256 ], [ 31.200826, 30.026512 ], [ 31.201257, 30.02592 ], [ 31.201463, 30.025147 ], [ 31.20167, 30.026648 ] ] } },
9 { "type": "Feature", "properties": { "station_name_en": "Dokki", "station_name_ar": "الدقي" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.211926, 30.038446 ], [ 31.212858, 30.038563 ], [ 31.213071, 30.039014 ], [ 31.213408, 30.037575 ] ] } },
10 { "type": "Feature", "properties": { "station_name_en": "El Demerdash", "station_name_ar": "الدمرداش" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.272726, 30.079096 ], [ 31.272841, 30.079167 ], [ 31.273817, 30.078925 ], [ 31.274032, 30.079479 ] ] } },
11 { "type": "Feature", "properties": { "station_name_en": "El Malek El Saleh", "station_name_ar": "الملك الصالح" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.233442, 30.019095 ], [ 31.233473, 30.018682 ], [ 31.234504, 30.017367 ], [ 31.234545, 30.017379 ] ] } },
12 { "type": "Feature", "properties": { "station_name_en": "El-Marg", "station_name_ar": "المرج" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.334217, 30.146468 ], [ 31.334253, 30.146538 ], [ 31.334782, 30.146493 ] ] } },
13 { "type": "Feature", "properties": { "station_name_en": "Ghamra", "station_name_ar": "غمرة" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.263164, 30.068985 ], [ 31.263197, 30.068259 ], [ 31.264394, 30.068864 ] ] } },
14 { "type": "Feature", "properties": { "station_name_en": "Hadayek El-Zaitoun", "station_name_ar": "حدائق الزيتون" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.3063, 30.122913 ], [ 31.30776, 30.123157 ], [ 31.307789, 30.122103 ], [ 31.307849, 30.12264 ] ] } },
15 { "type": "Feature", "properties": { "station_name_en": "Helmeyet El-Zaitoun", "station_name_ar": "حلمية الزيتون" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.302031, 30.11224 ], [ 31.302815, 30.111791 ], [ 31.303183, 30.111908 ] ] } },
16 { "type": "Feature", "properties": { "station_name_en": "Helwan", "station_name_ar": "حلوان" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.333401, 29.847533 ], [ 31.333518, 29.84856 ], [ 31.33383, 29.849118 ], [ 31.33423, 29.849025 ] ] } },
17 { "type": "Feature", "properties": { "station_name_en": "Maadi", "station_name_ar": "المعادي" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.256977, 29.960391 ], [ 31.256996, 29.961004 ], [ 31.25776, 29.95986 ], [ 31.25825, 29.959814 ], [ 31.258343, 29.961018 ] ] } },
18 { "type": "Feature", "properties": { "station_name_en": "Manshiet El-Sadr", "station_name_ar": "منشية الصدر" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.286919, 30.07915 ], [ 31.287036, 30.078534 ], [ 31.287853, 30.078947 ] ] } },
19 { "type": "Feature", "properties": { "station_name_en": "Mar Girgis", "station_name_ar": "مار جرجس" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.229596, 30.005582 ], [ 31.230357, 30.006424 ], [ 31.230863, 30.006943 ] ] } },
20 { "type": "Feature", "properties": { "station_name_en": "Mohamed Naguib", "station_name_ar": "محمد نجيب" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.245937, 30.043448 ], [ 31.246011, 30.042638 ], [ 31.246072, 30.042795 ], [ 31.246112, 30.043492 ] ] } },
21 { "type": "Feature", "properties": { "station_name_en": "Nasser", "station_name_ar": "عبد الناصر" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.243015, 30.052462 ], [ 31.243026, 30.053981 ], [ 31.244356, 30.052241 ], [ 31.244365, 30.053045 ] ] } },
22 { "type": "Feature", "properties": { "station_name_en": "Opera", "station_name_ar": "الأوبرا" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.223629, 30.042483 ], [ 31.22406, 30.041978 ], [ 31.224966, 30.042008 ] ] } },
23 { "type": "Feature", "properties": { "station_name_en": "Saad Zaghloul", "station_name_ar": "سعد زغلول" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.248006, 30.037688 ], [ 31.248884, 30.037798 ], [ 31.248954, 30.037359 ] ] } },
24 { "type": "Feature", "properties": { "station_name_en": "Sadat", "station_name_ar": "السادات" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.235032, 30.043948 ], [ 31.236163, 30.044623 ], [ 31.236249, 30.044071 ], [ 31.236357, 30.043795 ], [ 31.236493, 30.044874 ] ] } },
25 { "type": "Feature", "properties": { "station_name_en": "Sayeda Zeinab", "station_name_ar": "السيدة زينب" }, "geometry": { "type": "MultiPoint", "coordinates": [ [ 31.238434, 30.030095 ], [ 31.23933, 30.028708 ], [ 31.239612, 30.029943 ], [ 31.239711, 30.028807 ] ] } }
26 ]
27 }
0:15
The GeoJSON has 20 features, each with a MultiPoint geometry (the entrances). I need to compute the convex hull of each station's entrances and save as a Polygon per station. Let me write a Python script using geopandas and shapely to do this.
0:15
Write
/work/solve.py
content · 52 lines · py
import geopandas as gpd
from shapely.geometry import MultiPoint, Polygon
import json
# Read the input GeoJSON
gdf = gpd.read_file("/work/cairo_metro_stations.geojson")
# List to collect output features
features = []
for idx, row in gdf.iterrows():
# Get the MultiPoint geometry
geom = row.geometry
# Extract the points and compute convex hull
if geom.geom_type == "MultiPoint":
hull = geom.convex_hull # Returns a Polygon
else:
# If it's a single point, convex hull would be a Point, but we need Polygon
hull = geom.convex_hull
# Ensure it's a Polygon (if only 1 or 2 points, convex_hull could be Point or LineString)
if hull.geom_type == "Point":
# Buffer the point slightly to make a polygon
hull = hull.buffer(0.00001, resolution=4)
elif hull.geom_type == "LineString":
hull = hull.buffer(0.00001, resolution=4, cap_style=2, join_style=2)
# Create output feature
feature = {
"type": "Feature",
"properties": {
"station_name_en": row["station_name_en"],
"station_name_ar": row["station_name_ar"]
},
"geometry": hull.__geo_interface__
}
features.append(feature)
# Build the output FeatureCollection
out_fc = {
"type": "FeatureCollection",
"crs": {"type": "name", "properties": {"name": "urn:ogc:def:crs:OGC:1.3:CRS84"}},
"features": features
}
# Write with proper encoding for Arabic characters
with open("/work/cairo_metro_hulls.geojson", "w", encoding="utf-8") as f:
json.dump(out_fc, f, ensure_ascii=False, indent=2)
print(f"Processed {len(features)} stations.")
print("Output written to /work/cairo_metro_hulls.geojson")Wrote /work/solve.py (1715 chars).
0:41
Let me run this script to see if it works.
0:41
Bash
cd /work && python solve.py
Processed 20 stations. Output written to /work/cairo_metro_hulls.geojson
0:44
Let me verify the output looks correct.
0:44
Read
/work/cairo_metro_hulls.geojson
1 {
2 "type": "FeatureCollection",
3 "crs": {
4 "type": "name",
5 "properties": {
6 "name": "urn:ogc:def:crs:OGC:1.3:CRS84"
7 }
8 },
9 "features": [
10 {
11 "type": "Feature",
12 "properties": {
13 "station_name_en": "Al-Shohadaa",
14 "station_name_ar": "الشهداء"
15 },
16 "geometry": {
17 "type": "Polygon",
18 "coordinates": [
19 [
20 [
21 31.247736,
22 30.061538
23 ],
24 [
25 31.246778,
26 30.062428
27 ],
28 [
29 31.246441,
30 30.063109
31 ],
32 [
33 31.246859,
34 30.063158
35 ],
36 [
37 31.247931,
38 30.062636
39 ],
40 [
41 31.247736,
42 30.061538
43 ]
44 ]
45 ]
46 }
47 },
48 {
49 "type": "Feature",
50 "properties": {
51 "station_name_en": "Attaba",
52 "station_name_ar": "العتبة"
53 },
54 "geometry": {
55 "type": "Polygon",
56 "coordinates": [
57 [
58 [
59 31.246196,
60 30.051508
61 ],
62 [
63 31.246396,
64 30.051849
65 ],
66 [
67 31.246936,
68 30.052384
69 ],
70 [
71 31.247559,
72 30.052018
73 ],
74 [
75 31.246196,
76 30.051508
77 ]
78 ]
79 ]
80 }
81 },
82 {
83 "type": "Feature",
84 "properties": {
85 "station_name_en": "Cairo University",
86 "station_name_ar": "جامعة القاهرة"
87 },
88 "geometry": {
89 "type": "Polygon",
90 "coordinates": [
91 [
92 [
93 31.201463,
94 30.025147
95 ],
96 [
97 31.200216,
98 30.025256
99 ],
100 [
101 31.200826,
102 30.026512
103 ],
104 [
105 31.20167,
106 30.026648
107 ],
108 [
109 31.201463,
110 30.025147
111 ]
112 ]
113 ]
114 }
115 },
116 {
117 "type": "Feature",
118 "properties": {
119 "station_name_en": "Dokki",
120 "station_name_ar": "الدقي"
121 },
122 "geometry": {
123 "type": "Polygon",
124 "coordinates": [
125 [
126 [
127 31.213408,
128 30.037575
129 ],
130 [
131 31.211926,
132 30.038446
133 ],
134 [
135 31.213071,
136 30.039014
137 ],
138 [
139 31.213408,
140 30.037575
141 ]
142 ]
143 ]
144 }
145 },
146 {
147 "type": "Feature",
148 "properties": {
149 "station_name_en": "El Demerdash",
150 "station_name_ar": "الدمرداش"
151 },
152 "geometry": {
153 "type": "Polygon",
154 "coordinates": [
155 [
156 [
157 31.273817,
158 30.078925
159 ],
160 [
161 31.272726,
162 30.079096
163 ],
164 [
165 31.272841,
166 30.079167
167 ],
168 [
169 31.274032,
170 30.079479
171 ],
172 [
173 31.273817,
174 30.078925
175 ]
176 ]
177 ]
178 }
179 },
180 {
181 "type": "Feature",
182 "properties": {
183 "station_name_en": "El Malek El Saleh",
184 "station_name_ar": "الملك الصالح"
185 },
186 "geometry": {
187 "type": "Polygon",
188 "coordinates": [
189 [
190 [
191 31.234504,
192 30.017367
193 ],
194 [
195 31.233473,
196 30.018682
197 ],
198 [
199 31.233442,
200 30.019095
201 ],
202 [
203 31.234545,
204 30.017379
205 ],
206 [
207 31.234504,
208 30.017367
209 ]
210 ]
211 ]
212 }
213 },
214 {
215 "type": "Feature",
216 "properties": {
217 "station_name_en": "El-Marg",
218 "station_name_ar": "المرج"
219 },
220 "geometry": {
221 "type": "Polygon",
222 "coordinates": [
223 [
224 [
225 31.334217,
226 30.146468
227 ],
228 [
229 31.334253,
230 30.146538
231 ],
232 [
233 31.334782,
234 30.146493
235 ],
236 [
237 31.334217,
238 30.146468
239 ]
240 ]
241 ]
242 }
243 },
244 {
245 "type": "Feature",
246 "properties": {
247 "station_name_en": "Ghamra",
248 "station_name_ar": "غمرة"
249 },
250 "geometry": {
251 "type": "Polygon",
252 "coordinates": [
253 [
254 [
255 31.263197,
256 30.068259
257 ],
258 [
259 31.263164,
260 30.068985
261 ],
262 [
263 31.264394,
264 30.068864
265 ],
266 [
267 31.263197,
268 30.068259
269 ]
270 ]
271 ]
272 }
273 },
274 {
275 "type": "Feature",
276 "properties": {
277 "station_name_en": "Hadayek El-Zaitoun",
278 "station_name_ar": "حدائق الزيتون"
279 },
280 "geometry": {
281 "type": "Polygon",
282 "coordinates": [
283 [
284 [
285 31.307789,
286 30.122103
287 ],
288 [
289 31.3063,
290 30.122913
291 ],
292 [
293 31.30776,
294 30.123157
295 ],
296 [
297 31.307849,
298 30.12264
299 ],
300 [
301 31.307789,
302 30.122103
303 ]
304 ]
305 ]
306 }
307 },
308 {
309 "type": "Feature",
310 "properties": {
311 "station_name_en": "Helmeyet El-Zaitoun",
312 "station_name_ar": "حلمية الزيتون"
313 },
314 "geometry": {
315 "type": "Polygon",
316 "coordinates": [
317 [
318 [
319 31.302815,
320 30.111791
321 ],
322 [
323 31.302031,
324 30.11224
325 ],
326 [
327 31.303183,
328 30.111908
329 ],
330 [
331 31.302815,
332 30.111791
333 ]
334 ]
335 ]
336 }
337 },
338 {
339 "type": "Feature",
340 "properties": {
341 "station_name_en": "Helwan",
342 "station_name_ar": "حلوان"
343 },
344 "geometry": {
345 "type": "Polygon",
346 "coordinates": [
347 [
348 [
349 31.333401,
350 29.847533
351 ],
352 [
353 31.333518,
354 29.84856
355 ],
356 [
357 31.33383,
358 29.849118
359 ],
360 [
361 31.33423,
362 29.849025
363 ],
364 [
365 31.333401,
366 29.847533
367 ]
368 ]
369 ]
370 }
371 },
372 {
373 "type": "Feature",
374 "properties": {
375 "station_name_en": "Maadi",
376 "station_name_ar": "المعادي"
377 },
378 "geometry": {
379 "type": "Polygon",
380 "coordinates": [
381 [
382 [
383 31.25825,
384 29.959814
385 ],
386 [
387 31.25776,
388 29.95986
389 ],
390 [
391 31.256977,
392 29.960391
393 ],
394 [
395 31.256996,
396 29.961004
397 ],
398 [
399 31.258343,
400 29.961018
401 ],
402 [
403 31.25825,
404 29.959814
405 ]
406 ]
407 ]
408 }
409 },
410 {
411 "type": "Feature",
412 "properties": {
413 "station_name_en": "Manshiet El-Sadr",
414 "station_name_ar": "منشية الصدر"
415 },
416 "geometry": {
417 "type": "Polygon",
418 "coordinates": [
419 [
420 [
421 31.287036,
422 30.078534
423 ],
424 [
425 31.286919,
426 30.07915
427 ],
428 [
429 31.287853,
430 30.078947
431 ],
432 [
433 31.287036,
434 30.078534
435 ]
436 ]
437 ]
438 }
439 },
440 {
441 "type": "Feature",
442 "properties": {
443 "station_name_en": "Mar Girgis",
444 "station_name_ar": "مار جرجس"
445 },
446 "geometry": {
447 "type": "Polygon",
448 "coordinates": [
449 [
450 [
451 31.229596,
452 30.005582
453 ],
454 [
455 31.230357,
456 30.006424
457 ],
458 [
459 31.230863,
460 30.006943
461 ],
462 [
463 31.229596,
464 30.005582
465 ]
466 ]
467 ]
468 }
469 },
470 {
471 "type": "Feature",
472 "properties": {
473 "station_name_en": "Mohamed Naguib",
474 "station_name_ar": "محمد نجيب"
475 },
476 "geometry": {
477 "type": "Polygon",
478 "coordinates": [
479 [
480 [
481 31.246011,
482 30.042638
483 ],
484 [
485 31.245937,
486 30.043448
487 ],
488 [
489 31.246112,
490 30.043492
491 ],
492 [
493 31.246072,
494 30.042795
495 ],
496 [
497 31.246011,
498 30.042638
499 ]
500 ]
501 ]
502 }
503 },
504 {
505 "type": "Feature",
506 "properties": {
507 "station_name_en": "Nasser",
508 "station_name_ar": "عبد الناصر"
509 },
510 "geometry": {
511 "type": "Polygon",
512 "coordinates": [
513 [
514 [
515 31.244356,
516 30.052241
517 ],
518 [
519 31.243015,
520 30.052462
521 ],
522 [
523 31.243026,
524 30.053981
525 ],
526 [
527 31.244365,
528 30.053045
529 ],
530 [
531 31.244356,
532 30.052241
533 ]
534 ]
535 ]
536 }
537 },
538 {
539 "type": "Feature",
540 "properties": {
541 "station_name_en": "Opera",
542 "station_name_ar": "الأوبرا"
543 },
544 "geometry": {
545 "type": "Polygon",
546 "coordinates": [
547 [
548 [
549 31.22406,
550 30.041978
551 ],
552 [
553 31.223629,
554 30.042483
555 ],
556 [
557 31.224966,
558 30.042008
559 ],
560 [
561 31.22406,
562 30.041978
563 ]
564 ]
565 ]
566 }
567 },
568 {
569 "type": "Feature",
570 "properties": {
571 "station_name_en": "Saad Zaghloul",
572 "station_name_ar": "سعد زغلول"
573 },
574 "geometry": {
575 "type": "Polygon",
576 "coordinates": [
577 [
578 [
579 31.248954,
580 30.037359
581 ],
582 [
583 31.248006,
584 30.037688
585 ],
586 [
587 31.248884,
588 30.037798
589 ],
590 [
591 31.248954,
592 30.037359
593 ]
594 ]
595 ]
596 }
597 },
598 {
599 "type": "Feature",
600 "properties": {
601 "station_name_en": "Sadat",
602 "station_name_ar": "السادات"
603 },
604 "geometry": {
605 "type": "Polygon",
606 "coordinates": [
607 [
608 [
609 31.236357,
610 30.043795
611 ],
612 [
613 31.235032,
614 30.043948
615 ],
616 [
617 31.236493,
618 30.044874
619 ],
620 [
621 31.236357,
622 30.043795
623 ]
624 ]
625 ]
626 }
627 },
628 {
629 "type": "Feature",
630 "properties": {
631 "station_name_en": "Sayeda Zeinab",
632 "station_name_ar": "السيدة زينب"
633 },
634 "geometry": {
635 "type": "Polygon",
636 "coordinates": [
637 [
638 [
639 31.23933,
640 30.028708
641 ],
642 [
643 31.238434,
644 30.030095
645 ],
646 [
647 31.239612,
648 30.029943
649 ],
650 [
651 31.239711,
652 30.028807
653 ],
654 [
655 31.23933,
656 30.028708
657 ]
658 ]
659 ]
660 }
661 }
662 ]
663 }
0:51
The output looks correct. Let me verify a few things: 1. All 20 stations are present ✓ 2. Each feature has `station_name_en` and `station_name_ar` ✓ 3. The Arabic strings are preserved exactly as in the input (I can see الشهداء, العتبة, جامعة القاهرة, etc.) ✓ 4. Each geometry is a Polygon (convex hull of the MultiPoint) ✓ 5. The CRS is preserved ✓ Let me also double-check the Sadat station case - the input has 5 points for Sadat, but the convex hull output shows a triangle (4 coordinates, first repeated). Let me check... The input for Sadat: ``` [ [ 31.235032, 30.043948 ], [ 31.236163, 30.044623 ], [ 31.236249, 30.044071 ], [ 31.236357, 30.043795 ], [ 31.236493, 30.044874 ] ] ``` The hull output: ``` [ [ 31.236357, 30.043795 ], [ 31.235032, 30.043948 ], [ 31.236493, 30.044874 ], [ 31.236357, 30.043795 ] ] ``` So it's a triangle formed by the extreme points, which is correct for a convex hull. Wait, but what about the Nasser station? Input has 4 points: ``` [ [ 31.243015, 30.052462 ], [ 31.243026, 30.053981 ], [ 31.244356, 30.052241 ], [ 31.244365, 30.053045 ] ] ``` Output hull: ``` [ [ 31.244356, 30.052241 ], [ 31.243015, 30.052462 ], [ 31.243026, 30.053981 ], [ 31.244365, 30.053045 ], [ 31.244356, 30.052241 ] ] ``` That's a quadrilateral (4 unique points), which makes sense since all 4 points are extreme. All looks good. The output file is `/work/cairo_metro_hulls.geojson` as requested.
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