Adapt code for Point in Polygon, for multiple polygons, and refine search to optimize time

Hi DanSanDST ,

Looking at your code, the issue is that you're only getting the first polygon per zone because List.PositionOf() returns the first occurrence. You need to iterate through all polygons in a zone and return which one contains the point.

Here's a modified approach:

= (lat as number, lon as number, Poligonos4 as table, zona as text) as record => 
let
    // Filter polygons to only the matching zone
    FilteredPolygons = Table.SelectRows(Poligonos4, each [zona] = zona),
    
    // Function to check if point is in a single polygon
    PointInPolygon = (wktPolygon as text) =>
        let
            Polylist = Geometry.FromWellKnownText(wktPolygon)[Rings]{0}[Points],
            Edges = List.Zip({List.RemoveLastN(Polylist,1),List.RemoveFirstN(Polylist,1)}),
            Crossed = List.Select(Edges,each 
                (_{0}[Y]>lat <> _{1}[Y]>lat) 
                  and 
                (lon < (_{0}[X]-_{1}[X]) * (lat-_{1}[Y]) / (_{0}[Y]-_{1}[Y]) + _{1}[X])
            ),
            Result = Number.IsOdd(List.Count(Crossed))
        in
            Result,
    
    // Check each polygon in the zone
    PolygonResults = Table.AddColumn(FilteredPolygons, "Contains", 
        each PointInPolygon([value])),
    
    // Get the first polygon that contains the point
    MatchingPolygon = Table.SelectRows(PolygonResults, each [Contains] = true),
    
    // Return result record
    Result = if Table.RowCount(MatchingPolygon) > 0 
        then [
            IsInPolygon = true,
            PolygonName = MatchingPolygon[PlaceName]{0},
            Zone = zona
        ]
        else [
            IsInPolygon = false,
            PolygonName = null,
            Zone = zona
        ]
in
    Result

Then in your main query:

= Table.AddColumn(Points, "PolygonResult", 
    each CheckPointInPolygons([LATITUD], [LONGITUD], Poligonos4, [zona]))

To expand the record into separate columns:

= Table.ExpandRecordColumn(#"Added Custom", "PolygonResult", 
    {"IsInPolygon", "PolygonName", "Zone"})

This approach:

1. Filters polygons to only the matching zone (optimization)
2. Checks each polygon in that zone
3. Returns the first match with polygon name and zone
4. Returns a record instead of just boolean, so you get all the info you need

This should be much faster since it only searches relevant polygons per zone.

If my response resolved your query, kindly mark it as the Accepted Solution to assist others. Additionally, I would be grateful for a 'Kudos' if you found my response helpful.
This response was assisted by AI for translation and formatting purposes.