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terrastudios · #1 (**permalink**) 10-30-2005

All,

I have compiled together a class for using MapPoint (currently 2004) with Delphi. The class creates MapPoint as an ole object, and will display it on any twincontrol (e.g. a panel). I have compiled some of the routines from code found on this forum - credit to the original authors. If anyone feels like extending/improving this class, then please feel free - all I ask is that you can share your results with the rest of the members on this forum so that others can benefit from it too.

Many thanks in advance and I hope its of use to someone.

Regards

Matt Brocklehurst,
TerraStudios Limited.
----------

Code:

unit mappoint;

{

        TTSMapPoint Class

Author: Matt Brocklehurst

Ties various mappoint (ole) delphi routines together, uses code found at www.MP2KMag.com
Credit to the various authors of some of the routines I use.


}

interface

uses Controls, extCtrls, Classes, Variants, OleCtnrs, OleServer, MapPoint_TLB;

type
  TTSMapPoint = class
          constructor Create(AOwner: TComponent;ParentControl:TWinControl);
          destructor Destroy;
  private
          OleContainer1: TOleContainer;
          locNorthPole:Location;
          locSantaCruz:Location; //Center of western hemisphere
          Pi, dblHalfEarth, dblQuarterEarth:double;
          function Arccos(x:double):double;
          function GetStreetName2(Longitude,Latitude:double; out StreetName: string):boolean;
  public
          FMap: _Map; // the active map
          function GetLat(locx:Location):double;
          function GetLon(locx:Location):double;
          function GetStreetName(xlongitude,xlatitude:double):string;
          procedure GetLatLonPostcode(Postcode:string; out Longitude,Latitude: double);
  end;

implementation

constructor TTSMapPoint.Create(AOwner: TComponent;ParentControl:TWinControl);
var
     vGuid: TGuid;
begin;
         OleContainer1:=TOleContainer.create(aowner);
         OleContainer1.Width:=ParentControl.Width;
         OleContainer1.Height:=ParentControl.height;
         OleContainer1.Parent:=ParentControl;
         OleContainer1.CreateObject('MapPoint.Map.EU.11',False);
         OleContainer1.DoVerb(1);
         OleContainer1.OleObjectInterface.GetUserClassID(vGuid);
         FMap:= IDispatch(OleContainer1.OleObject) as map;
         locNorthPole:=fmap.GetLocation(90,0,0);
         locSantaCruz:=fmap.GetLocation(0,-90,0);
         dblHalfEarth:=fmap.Distance(locNorthPole, fmap.GetLocation(-90, 0,0));
         dblQuarterEarth:=dblHalfEarth/2;
         Pi:=3.14159265358979;
end;

destructor TTSMapPoint.Destroy;
begin;
        FMap:=nil;
        OleContainer1.DestroyObject;
        // OleContainer1.Destroy;
end;


function TTSMapPoint.Arccos(x:double):double;
var
        ret:double;
begin
        if x=1 then
                ret:=0
        else
                ret:=ArcTan(-x/Sqrt(-x*x+1))+2*ArcTan(1);
        result:=ret;
end;

function TTSMapPoint.GetLat(locx:Location):double;
var
        ret:double;
begin
        ret:=90 - 180 * fmap.Distance(locNorthPole, locX) / dblHalfEarth;
        result:=ret;
end;

function TTSMapPoint.GetLon(locx:Location):double;
var
        ret, l , d , lat:double;
begin
        lat:=GetLat(locx);
        d:= fmap.Distance(fmap.GetLocation(lat, 0, 0), locX);
        l:= (Lat / 180) * Pi;
        ret:= 180 * Arccos((Cos((d * 2 * Pi) / (2 * dblHalfEarth)) - Sin(l) * Sin(l)) / (Cos(l) * Cos(l))) / Pi;
        If fmap.Distance(locSantaCruz, locX) < dblQuarterEarth Then ret:= -ret;
        result:=ret;
end;

function TTSMapPoint.GetStreetName2(Longitude,Latitude:double; out StreetName: string):boolean;
var
        vFindResult : FindResults;
        vStreetAddress : StreetAddress;
        vResult : string;
        i : integer;
        iOle : OleVariant;
        Loc: Location;
        GoodHit: boolean;
begin
        Loc:=FMap.GetLocation(longitude,latitude,1);
        Loc.Goto_;
        vFindResult:=FMap.ObjectsFromPoint(FMap.LocationToX(Loc),FMap.LocationToY(Loc)) as FindResults;
        GoodHit:=false;
        for i := 1 to vFindResult.Count do
        begin
                iOle := i;
                vStreetAddress := (vFindResult[iOle] as Location).StreetAddress;
                if Assigned(vStreetAddress) then
                begin
                        StreetName:=(vStreetAddress.Street);
                        goodhit:=true;
                        break;
                end
                 else
                begin;
                        goodhit:=false;
                end;
        end;
        GetStreetName2:=goodhit;
end;

function TTSMapPoint.GetStreetName(xlongitude,xlatitude:double):string;
var
     longitude, latitude: double;
     oldlongitude,oldlatitude: double;
     streetname: string;
     flag: boolean;
     i: integer;
begin
     // for some reason longitude and latitude are back to front?
     // to avoid conversion - we flip em over for the purpose of our routines
     longitude:=xlatitude;
     latitude:=xlongitude;
     streetname:='';
     flag:=GetStreetName2(longitude,latitude,StreetName);
     if(flag) then exit;
     oldlongitude:=longitude;
     oldlatitude:=latitude;
     for i:=1 to 10 do
     begin;
             longitude:=longitude+0.001;
             flag:=GetStreetName2(longitude,latitude,StreetName);
             if(flag) then
             begin;
                     getstreetname:=streetname;
                     exit;
             end;
     end;
     latitude:=oldlatitude;
     longitude:=oldlongitude;
     for i:=1 to 10 do
     begin;
             longitude:=longitude-0.001;
             flag:=GetStreetName2(longitude,latitude,StreetName);
             if(flag) then
             begin;
                     getstreetname:=streetname;
                     exit;
             end;
     end;
     latitude:=oldlatitude;
     longitude:=oldlongitude;
     for i:=1 to 10 do
     begin;
             latitude:=latitude-0.001;
             flag:=GetStreetName2(longitude,latitude,StreetName);
             if(flag) then
             begin;
                     getstreetname:=streetname;
                     exit;
             end;
     end;
     latitude:=oldlatitude;
     longitude:=oldlongitude;
     for i:=1 to 10 do
     begin;
             latitude:=latitude+0.001;
             flag:=GetStreetName2(longitude,latitude,StreetName);
             if(flag) then
             begin;
                     getstreetname:=streetname;
                     exit;
             end;
     end;

     getstreetname:='';
end;

procedure TTSMapPoint.GetLatLonPostcode(Postcode:string; out Longitude,Latitude: double);
var
     vFindResult : FindResults;
     vStreetAddress : StreetAddress;
     loc: location;
     iOle: olevariant;
     i: integer;
begin;
     vFindResult:=FMap.FindAddressResults('','','','',postcode,0);
     for i := 1 to vFindResult.Count do
     begin
           iOle := i;
           loc:=(vFindResult[iOle] as Location);
           if(assigned(loc)) then
           begin;
             latitude:=getlat(loc);
             longitude:=getlon(loc);
             exit;
           end;
     end;
end;

end.

**Wilfried** · #2 (**permalink**) 11-02-2005

Hi,

I tryed your class in Delphi 7. Works as a glance, however some strange things:

If I make a panel bottom aligned, and a second panel client alignd (for MP), then my bottom alligned pannel dissapears... also resizing does not resize the map.

If I only 1 panel bottom aligned and visual the map on the form then I can make my panel visible by making the form larger at runtime, but again the map anchors does not follow the form.

OK I did only quick test. but your comments are welcome of course.

**Wilfried** · #3 (**permalink**) 11-02-2005

Hi,

this is of course solution for the resize. Still other panel dissapears. Will look at it later.

Code:

         OleContainer1.Align := alClient;

**Wilfried** · #4 (**permalink**) 11-02-2005

Hi,

I could not stop

Setting the panel to Aligne=alNone, and his Anchors to top+left+bottom+right then MP will resize perfect (see also my previous mail) and the other panel stay visible

**Wilfried** · #5 (**permalink**) 11-02-2005

Hi,

this is interesting:

Drop a MainMenu on the form ! And see what happens, automaticely without any letter of code I have the whole Mappoint menu and working.....

This can be sometime not wanted, but..

Adding menu items will merge with the Mappoint ones...

terrastudios · #6 (**permalink**) 11-03-2005

Hi!

Yep the menu bar is strange - but I guess in some instances it could be quite a useful feature.

Thanks for pointing out the resize problem (& solution) I will make this modification to the class.

I think that the "jump to the nearest street" bit of code I wrote is adequate atm, however I have seen a much much more clever solution (more maths than I can cope with!) on here (I believe by yourself Wilfried) so I might look at implementing this in the next revision.

Is there an easy way of disabling the right click menus/other menus and implementing a custom popup menu (I am guessing by catching an OnMouseDown event, detecting that button == mbRight, and displaying a tpopupmenu). I wish for this menu to display a save as bitmap item, is there an method to save the bitmap? I know there is a kludge which allows you to copy the current map to the tclipboard and then I can save it that way, but I do not feel this is a very good solution for an end product!

Cheers again,

Matt.

**Wilfried** · #7 (**permalink**) 11-03-2005

Hi,

I did not really test the methods you have provided, I was just anger to try it because I have a lot of Delhi applications using mappoint, ant this class is fine

For the jump to nearest street I think I have published some delphi code to use a vector. If you cannot find it then I post it again.

If you are going to expand the class I have following suggestion, because it is no nececary that a user (or even you yourself) do need all methods provided in a program. So I suggest to make a TTSCustomMappoint class where only the nececary things in to start and display mappoint. Then you can derrive components from it with the more advanced methods. For example I have a dozain applications where mappoint is only used to check the nearest street of a vehicle if it is not. Half of them do not even display a map, because position has to be sent to someone, like: "car is 50 meter NE from street name, no at zip city", or "car is in street name, no at zip city".

It's your class of course, but only a suggestion

For the saveToClipBoard I have no other / better idea's

terrastudios · #8 (**permalink**) 11-03-2005

Hi Wilfried,

Thats actually a great idea - keep TSMapPoint as a parent class and derive any custom methods etc.. from this as seperate child classes - inheritence is good for something!

I hope that it proves a useful class in some of your applications, I will look up the vector code that you wrote, and add it to a descendant (I will post the descendant on here as well for all to use).

Cheers

Matt.

KeithW · #9 (**permalink**) 11-30-2005

Quote:

Originally Posted by Wilfried

Hi,

I did not really test the methods you have provided, I was just anger to try it because I have a lot of Delhi applications using mappoint, ant this class is fine

For the jump to nearest street I think I have published some delphi code to use a vector. If you cannot find it then I post it again.

If you are going to expand the class I have following suggestion, because it is no nececary that a user (or even you yourself) do need all methods provided in a program. So I suggest to make a TTSCustomMappoint class where only the nececary things in to start and display mappoint. Then you can derrive components from it with the more advanced methods. For example I have a dozain applications where mappoint is only used to check the nearest street of a vehicle if it is not. Half of them do not even display a map, because position has to be sent to someone, like: "car is 50 meter NE from street name, no at zip city", or "car is in street name, no at zip city".

It's your class of course, but only a suggestion

For the saveToClipBoard I have no other / better idea's

Hi Terrastudio / Wilfred
I to just need to be able to get Street location without the MAP but am unsure on how to inherit Classes etc.
Have you extended your class to enable this yet ( Hoping ).

BTW I think theres a small bug in the GetStreetName function that fails if you are Exactly on the Street.

Code:

function TTSMapPoint.GetStreetName(xlongitude,xlatitude:double):string; 
....
     flag:=GetStreetName2(longitude,latitude,StreetName); 
     if(flag) then exit; 
     oldlongitude:=longitude; 
     oldlatitude:=latitude;

I Think it should be

Code:

function TTSMapPoint.GetStreetName(xlongitude,xlatitude:double):string; 
....
     flag:=GetStreetName2(longitude,latitude,StreetName); 
     if(flag) then 
     begin
         getstreetname := streetname;
         exit; 
     end;
     oldlongitude:=longitude; 
     oldlatitude:=latitude;

Thanks for the Class

**Wilfried** · #10 (**permalink**) 12-02-2005

Hi,

You right. In first example the return value of the function is undefined. Compiler should generate a warning also.

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