[lmikle]

Как-то так:

Код:

unit Unit2;

interface

uses
  SysUtils, Windows, Classes, Math;

type
  gmaps = class
  public
    function tile(lat, lng : Double; zoom : Integer) : TPoint;
    function Xpixel(lng : Double; zoom : Integer) : Integer;
    function Ypixel(lat : Double; zoom : Integer) : Integer;
  end;
implementation

{ gmaps }

function gmaps.tile(lat, lng: Double; zoom: Integer): TPoint;
begin
  Result.X := Round(Xpixel(lng, zoom) / 256);
  Result.Y := Round(Ypixel(lat, zoom));
end;

function gmaps.Xpixel(lng: Double; zoom: Integer): Integer;
var
  dlng : Double;
  dxpixel : Double;
begin
  dlng := lng + 180; // this.lng.Value + 180.0; <- не понятно, что за this.lng.Value

  dxpixel := dlng / 360.0 * 256 * Power(2, 17 - zoom);
  Result := Round(dxpixel);
end;

function gmaps.Ypixel(lat: Double; zoom: Integer): Integer;
var
  ypixelcenter : Double;
  dypixel : Double;
begin
  ypixelcenter := Power(2, 25 - zoom - 1);

  dypixel := ypixelcenter - Ln(Tan(lat * PI / 360 + PI / 4)) * ypixelcenter / PI;
  Result := Round(dypixel);
end;

end.