function LoadGeoJSONPolyline (AFilename: string; AColor: TColor = clBlue; Opacity: Integer = 255; AWidth: Integer = 2; Zoom: Boolean = True; HoverColor: TColor = clBlue): string

Description

This function loads coordinates from a GEOJSON file and displays it on the map as a Polyline or Polylines. Optionally set the Color, Opacity, Width, HoverColor of the Polyline(s). Optionally set Zoom to true to automatically zoom the map to the bounds of the Polyline(s).

Function parameters:

Parameter	Type	Description
AFilename	String	GeoJSON file name.
AColor	TColor	The color that will be used to draw the polyline. The default color is blue. Optional parameter.
Opacity	Integer	The degree of transparency of the polyline. Values from 0 to 255. Optional parameter.
AWidth	Integer	The width of the polyline. The default width is two pixels. Optional parameter.
Zoom	Boolean	Determine whether the polyline should be automatically shown on the map. Optional parameter.
HoverColor	TColor	The color the polyline 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": "Polyline1"
},

"geometry":{
"type": "LineString",
"coordinates": [[
[-105.431410315776, 20.878495854271],
[-105.445432904506, 20.8727217105441],
[-105.451183560633, 20.8762102822492]
]]
}
},

{
"type":"Feature",
"properties": {
"name":"Polyline2"
},

"geometry":{
"type": "LineString",
"coordinates": [[
[-105.491410315776, 20.878495854271],
[-105.495432904506, 20.8727217105441],
[-105.491183560633, 20.8762102822492]
]]
}
}

]
}

Read more about the GeoJSON format here https://geojson.org/

Example

Form1.Map1.LoadGeoJSONPolyline('D:\polylines.geojson');