Merge least feature count polygons with neighbouring polygons

[Sujanadh]

Description:

This PR introduces a feature to merge small polygons with their neighboring larger polygons based on shared boundary lengths. The goal is to ensure that polygons below a certain area threshold or containing fewer buildings are merged with their best-suited neighbor to avoid fragmentation.

Updates:

• A temporary table leastfeaturepolygons is created to store polygons smaller than the minimum area obtained from standard deviation or those with fewer than a dynamically calculated number of buildings which is half the number provided my user.

• A loop is implemented to iterate over all small polygons, finding the neighboring polygon that shares the longest boundary using ST_Length(ST_Intersection()).

• After identifying the best neighbor, the small polygon is merged into the larger one using ST_Union().
  Controlled Deletion:

• Small polygons are deleted from the taskpolygons table only after a successful merge, ensuring no polygon is prematurely removed and repeated or overlapped.

• The neighboring polygon is selected based on the maximum shared boundary, ensuring accurate merges.

• Added building count in the properties of geojson

Response:

{
      "type": "Feature",
      "geometry": {
        "type": "Polygon",
        "coordinates": [
          [
            [
              85.329736,
              27.798211563
            ],
            [
              85.330273109,
              27.798061799
            ],
            [
              85.331683065,
              27.797746463
            ],
            [
              85.331811757,
              27.797866055
            ],
            [
              85.33221594,
              27.79781169
            ],
            [
              85.332281149,
              27.797402154
            ],
            .
            .
            .
            [
              85.335539882,
              27.794265868
            ]
          ]
        ]
      },
      "properties": {
        "building_count": 130
      }
    }

Before:

num_buildings = 100

After:

num_buildings = 100

Issue

• Number of features on tasks should be approximately within range.  #52
  Further splitting if the task polygons contains more features (buildings) than the threshold is yet to be done.
• Fixes Filter out split geometries with too few buildings #28

[spwoodcock]

Going to approve this, as we can make the param configurable by the user in a future modular approach 👍

[spwoodcock]

💫

[spwoodcock]

Have you tried modifying this number a bit to see the result?

[spwoodcock]

0.5 is ok, but as a user I would imagine if they requested 15 buildings per task, but only got 8 they might be a bit disappointed 😅

Does 0.7 change things by a lot?

[spwoodcock]

This discrepancy will obviously scale linearly: say they request 50 buildings average and get 25 minimum.

But personally, I think if users are requesting 50 geoms per area there is something wrong with their methodology! I would imagine 10 buildings per task is more realistic for an individual or team 👍

[Sujanadh]

oh crap i didn't see these comments , yeah i had tried with params such as 0.7 but got so big tasks in result. Yeah we can change this in future based on the practical use case scenarios