function LoadGeoJSONPolygon (AFilename: string; BorderColor: TColor = clBlue; Opacity: Integer = 255; BackgroundColor: TColor = clBlue; BackgroundOpacity: Integer = 100; AWidth: Integer = 2; Zoom: Boolean = True; HoverBorderColor: TColor = clBlue; HoverBackgroundColor: TColor = clBlue): string




Description


This function loads coordinates from a GEOJSON file and displays it on the map as a Polygon or Polygons. Optionally set the BorderColor, Opacity, BackgroundColor, BackgroundOpacity, Width, HoverBorderColor, HoverBackgroundColor of the Polygon(s). Optionally set Zoom to true to automatically zoom the map to the bounds of the Polygon(s).



Function parameters:

 Parameter

 Type

 Description

 AFilename

 String

 GeoJSON file name.

 BorderColor

 TColor

 The color that will be used to border the polygons. The default color is blue. Optional parameter.

 Opacity

 Integer

 The degree of transparency of the polygon border. Values from 0 to 255. Optional parameter.

 BackgroundColor

 TColor

 The color that will be used to build the polygon. The default color is blue. Optional parameter.

 BackgroundOpacity

 Integer

 The degree of transparency of the polygons. Values from 1 to 100. Optional parameter.

 AWidth

 Integer

 The width of the border for polygons. The default width is two pixels. Optional parameter.

 Zoom

 Boolean

 Determine whether the polyline should be automatically shown on the map. Optional parameter.

 HoverBorderColor

 TColor

 The color that the border of the polygon will have when the mouse cursor is over it. The default color is blue. Optional parameter.

 HoverBackgroundColor

 TColor

 The color the polygon will have when the mouse cursor is over it. The default color is blue. Optional parameter.




An example of a GeoJSON file:


{
    "type":"FeatureCollection","features":[
        {
            "type":"Feature",
            "properties": {
                "name":"Polygon1"
            },
           
            "geometry":{
                "type":"Polygon",
                "coordinates": [[
                    [-105.431410315776, 20.878495854271],
                    [-105.445432904506, 20.8727217105441],
                    [-105.451183560633, 20.8762102822492]
                ]]
            }
        },
       
       
        {
            "type":"Feature",
            "properties": {
                "name":"Polygon2"
            },
           
            "geometry":{
                "type":"Polygon",
                "coordinates": [[
                    [-105.491410315776, 20.878495854271],
                    [-105.495432904506, 20.8727217105441],
                    [-105.491183560633, 20.8762102822492]
                ]]
            }
        }       
       
       
    ]
}




Подробней о GeoJSON формате можно прочитать здесь https://geojson.org/





Example


Form1.Map1.LoadGeoJSONPolygon('D:\polygons.geojson');