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by **betoncu** » Fri Jan 11, 2019 2:54 am

How can I get the latitude and longitude of a place clicked by a user on the map.
Thanks in advance

by **anserkk** » Fri Jan 11, 2019 6:54 am

Please try the following code.

Remember Google has changed its policies last July. Now, to use maps, Google requires you to register with them and then obtain an API key from them. You should use your Google Maps Javascript API key in your code to view the Map.

Once you have the API key with you, the following code will work. I tested it here with my API key and is working fine.

The code will show the lat and lon of the place when you move your mouse, if you click on a point on the map, it will place a marker where you have clicked. It will also show the lat and lon of the last clicked place above the Map window

Code: Select all Expand view RUN: #Include "FiveWin.ch" //----------------------------- Function Main() ViewGoogleMap() Return NIL //-----------------------------------------------------------------------/ Function ViewGoogleMap() Local cMapFile:="D:\GMaps.htm", cHtmlContent TEXT INTO cHtmlContent <html> <head> <title>Google Map</title> <meta name="viewport" content="initial-scale=1.0"> <meta charset="utf-8"> <style> #map { height: 500px; width: 900px; } </style> </head> <body> <div id="latclicked"></div> <div id="longclicked"></div> <div id="latmoved"></div> <div id="longmoved"></div> <div style="padding:10px"> <div id="map"></div> </div> <script type="text/javascript"> var map; function initMap() { var latitude = 27.7172453; // YOUR LATITUDE VALUE var longitude = 85.3239605; // YOUR LONGITUDE VALUE var myLatLng = {lat: latitude, lng: longitude}; map = new google.maps.Map(document.getElementById('map'), { center: myLatLng, zoom: 14, disableDoubleClickZoom: true, // disable the default map zoom on double click }); // Update lat/long value of div when anywhere in the map is clicked google.maps.event.addListener(map,'click',function(event) { document.getElementById('latclicked').innerHTML = event.latLng.lat(); document.getElementById('longclicked').innerHTML = event.latLng.lng(); }); // Update lat/long value of div when you move the mouse over the map google.maps.event.addListener(map,'mousemove',function(event) { document.getElementById('latmoved').innerHTML = event.latLng.lat(); document.getElementById('longmoved').innerHTML = event.latLng.lng(); }); var marker = new google.maps.Marker({ position: myLatLng, map: map, //title: 'Hello World' // setting latitude & longitude as title of the marker // title is shown when you hover over the marker title: latitude + ', ' + longitude }); // Update lat/long value of div when the marker is clicked marker.addListener('click', function(event) { document.getElementById('latclicked').innerHTML = event.latLng.lat(); document.getElementById('longclicked').innerHTML = event.latLng.lng(); }); // Create new marker on double click event on the map google.maps.event.addListener(map,'dblclick',function(event) { var marker = new google.maps.Marker({ position: event.latLng, map: map, title: event.latLng.lat()+', '+event.latLng.lng() }); // Update lat/long value of div when the marker is clicked marker.addListener('click', function() { document.getElementById('latclicked').innerHTML = event.latLng.lat(); document.getElementById('longclicked').innerHTML = event.latLng.lng(); }); }); // Create new marker on single click event on the map google.maps.event.addListener(map,'click',function(event) { var marker = new google.maps.Marker({ position: event.latLng, map: map, title: event.latLng.lat()+', '+event.latLng.lng() }); }); } </script> <script src="https://maps.googleapis.com/maps/api/js?key=[YOUR API KEY HERE and remove the square brackets]&callback=initMap" async defer></script> </body> </html> ENDTEXT MEMOWRIT( cMapFile, cHtmlContent ) // Opens the Map using your default internet browser. A more generic solution Shellexecute( NIL, "open", cMapFile ) Return NIL

You may modify the code to suit your requirements

by **betoncu** » Sun Jan 13, 2019 10:59 am

Perfect. Many thanks.
Is it possible to pass the coordinates to the calling program?

by **anserkk** » Mon Jan 14, 2019 4:50 am

betoncu wrote:Perfect. Many thanks.
Is it possible to pass the coordinates to the calling program?

Instead of

Code: Select all Expand view RUN: Shellexecute( NIL, "open", cMapFile )

Use Internet Explorer and read the DIV values of latclicked and longclicked
For eg something like

Code: Select all Expand view RUN: oIE:=CreateObject("InternetExplorer.Application") oIE:Document:getElementsByName("latclicked"):Item(0):Value

by **betoncu** » Wed Jan 16, 2019 4:02 am

Sorry but I couldn't. Anyhow, thanks for your help.

by **AntoninoP** » Wed Jan 16, 2019 2:29 pm

Some time ago I did a FiveWin control that uses OpenStreetMap: viewtopic.php?f=3&t=35535

here an updated code:

Code: Select all Expand view RUN: #include <fivewin.ch> ********** TEST CODE ********** proc main LOCAL oWnd, oMap DEFINE WINDOW oWnd TITLE "3D objects" SetWndDefault(oWnd) oMap := TMapControl():New() oMap:SetCenter(-4.806640,36.505522) oMap:AddMarker(-4.806640,36.505522) oWnd:oClient := oMap ACTIVATE WINDOW oWnd ******************************* /// https://wiki.openstreetmap.org/wiki/Sli ... _tilenames class TMapControl FROM TControl CLASSDATA lRegistered AS LOGICAL CLASSDATA aServers AS ARRAY INIT {'https://a.tile.openstreetmap.org/{zoom}/{x}/{y}.png', ; 'https://b.tile.openstreetmap.org/{zoom}/{x}/{y}.png', ; 'https://c.tile.openstreetmap.org/{zoom}/{x}/{y}.png'} CLASSDATA nMaxZoom AS NUMERIC INIT 19 DATA oTimer DATA aHttps // Queue of downloading images, array of { "Msxml2.XMLHTTP.6.0", zoom, x, y, Seconds(), cUrl } DATA nZoom, nLat, nLon // current zoom and center of the screen DATA nServer // Last used server Id (from aServers) DATA aMarkers AS ARRAY INIT {} // Couples of lat+lon to mark on map DATA aImages AS ARRAY INIT {} // Array of loaded images DATA aTopLeftTileInfo // Information about tile at top left corner { xpos, ypos, x-tile, y-tile } DATA lastMousePos, lastRenderTime // mouse down position and seconds of last rendering METHOD New( nRow, nCol, oWnd, nWidth, nHeight ) CONSTRUCTOR METHOD End() METHOD Display() INLINE ::BeginPaint(),::Paint(),::EndPaint(),0 METHOD EraseBkGnd( ) INLINE 1 METHOD Paint() Method SetCenter(nLon,nLat) Method AddMarker(nLon,nLat) METHOD RButtonDown(nRow, nCol, nKeyFlags, lTouch) METHOD LButtonDown(nRow, nCol, nKeyFlags, lTouch) METHOD MouseMove( nRow, nCol, nKeyFlags ) METHOD MouseWheel( nKey, nDelta, nXPos, nYPos ) METHOD TimerEvent() METHOD GetImage(x,y,zoom,lQueue) HIDDEN METHOD GetTileNumber(lon,lat,zoom) METHOD GetCoordsFromTile(x,y,zoom) METHOD GetCoordsFromPixel(x,y) METHOD PaintTile(hDCMem,hDCBmp,l,t,tx,ty,zoom) endclass METHOD New( nRow, nCol, oWnd, nWidth, nHeight ) CLASS TMapControl DEFAULT nRow := 10, nCol := 10, oWnd := GetWndDefault() DEFAULT nWidth := 500 DEFAULT nHeight := 300 ::nZoom := 15 ::nLon := 0 ::nLat := 0 ::nServer := 1 ::aMarkers := {} ::oWnd := oWnd ::nId := ::GetNewId() ::nStyle := nOR( WS_CHILD, WS_VISIBLE, WS_TABSTOP, WS_BORDER ) ::nTop := nRow ::nLeft := nCol ::nBottom := ::nTop + nHeight - 1 ::nRight := ::nLeft + nWidth ::aHttps := {} ::Register( nOR( CS_VREDRAW, CS_HREDRAW ) ) if ! Empty( oWnd:hWnd ) ::Create( ) oWnd:AddControl( Self ) else oWnd:DefControl( Self ) endif DEFINE TIMER ::oTimer OF SELF INTERVAL 0.1 ACTION ::TimerEvent() ::oTimer:Activate() return Self METHOD End() class TMapControl if .not. empty(::oTimer) ::oTimer:Deactivate() ::oTimer:End() endif return ::Super:End() Method SetCenter(nLon,nLat) class TMapControl local r := {::nLon,::nLat} ::nLon := nLon ::nLat := nLat return r Method AddMarker(nLon,nLat) class TMapControl return aAdd(::aMarkers, {nLon,nLat}) #define SRCCOPY 13369376 METHOD Paint() class TMapControl LOCAL x,y, img, ix,iy, top, left, sx,sy, hBmpMem LOCAL w := ::nWidth, h := ::nHeight, hDCMem, hDCBmp hDCMem = CreateCompatibleDC( ::hDC ) hBmpMem = CreateCompatibleBitmap( ::hDC, w, h ) SelectObject( hDCMem, hBmpMem ) FillRect( hDCMem, {0,0,h,w}, ::oBrush:hBrush ) // get tile of center x := ::GetTileNumber(::nLon,::nLat) y := x[2] x := x[1] // move the desired pixel in the centre of canvas sx := floor(x) sy := floor(y) top := h/2 - int((y-sy)*256) left := w/2 - int((x-sx)*256) // check for fill all area do while top>0 sy-=1 top-=256 enddo do while left>0 sx-=1 left-=256 enddo // draw the map ::lastRenderTime := Seconds() hDCBmp := CreateCompatibleDC( ::hDC ) for iy:=0 to ceiling((h-top)/256) for ix:=0 to ceiling((w-left)/256) ::PaintTile(hDCMem,hDCBmp,left+ix*256,top+iy*256 ,sx+ix,sy+iy,::nZoom) next next DeleteDC( hDCBmp ) // draw the markers for ix:=1 to len(::aMarkers) x := ::GetTileNumber(::aMarkers[ix,1],::aMarkers[ix,2]) y := (x[2] - sy) * 256 + top x := (x[1] - sx) * 256 + left MoveTo(hDCMem,x-5,y-5) LineTo(hDCMem,x+5,y+5) MoveTo(hDCMem,x-5,y+5) LineTo(hDCMem,x+5,y-5) next // save these infos ::aTopLeftTileInfo := {top,left,sx,sy} //img := "Queue len: " + alltrim(str(len(::aHttps))) //TextOut( hDCMem, 4, 4, img, Len( img ) ) BitBlt( ::hDC, 0,0, w, h, hDCMem, 0,0, SRCCOPY ) DeleteDC(hDCMem) return nil METHOD PaintTile(hDCMem,hDCBmp,l,t,tx,ty,zoom) LOCAL img, sx,sy, ix, iy, n img := ::GetImage(tx,ty,zoom) if .not. empty(img) SelectObject(hDCBmp, img) BitBlt( hDCMem, l,t, 256, 256, hDCBmp, 0,0, SRCCOPY ) return nil endif // try less zoomed images (if they are not in cache it are not downloaded) img := ::GetImage(hb_bitShift(tx,-1),hb_bitShift(ty,-1),zoom-1,.F.) if .not. empty(img) SelectObject(hDCBmp, img) StretchBlt( hDCMem, l,t, 256, 256, hDCBmp, hb_bitAnd(tx,1)*128,hb_bitAnd(ty,1)*128,128,128, SRCCOPY ) return nil endif sx := hb_bitShift(tx,1) sy := hb_bitShift(ty,1) for iy:=0 to 1 for ix:=0 to 1 img := ::GetImage(sx+ix,sy+iy,zoom+1,.F.) if .not. empty(img) SelectObject(hDCBmp, img) StretchBlt( hDCMem, l+ix*128,t+iy*128, 128, 128, hDCBmp, 0,0,255,255, SRCCOPY ) endif next next return nil METHOD TimerEvent() class TMapControl LOCAL lRedraw := .F., oHttp, img, idx for idx:=1 to len(::aHttps) oHttp := ::aHttps[idx] if oHttp[1]:readyState = 4 // downloaded a missing image! img := GDIP_ImageFromStr(oHttp[1]:ResponseBody(), .t., .f.) if .not. empty(img) // correctly created lRedraw := .T. aAdd(::aImages, { img, oHttp[2], oHttp[3], oHttp[4] }) endif hb_ADel(::aHttps,idx,.t.) else // stop the unfinisched download that are not relative of current view if oHttp[5]<::lastRenderTime oHttp[1]:abort() hb_ADel(::aHttps,idx,.t.) endif endif next if lRedraw ::Refresh() endif return nil // directly from OpenStreetMap wiki METHOD GetTileNumber(lon,lat,zoom) class TMapControl LOCAL x,y,n, latRad DEFAULT zoom := ::nZoom n := hb_bitShift(1, zoom) latRad := lat * PI() / 180 x := n * (lon + 180) / 360 y := n * (1-(log(tan(latRad) + 1/cos(latRad)) / PI())) / 2 do while(x<0) x+=n enddo do while(x>=n) x-=n enddo if y<0 y:=0 endif if y>=n y:=n-1 endif return {x,y} // directly from OpenStreetMap wiki METHOD GetCoordsFromTile(x,y,zoom) class TMapControl LOCAL lon, lat, n, lat_rad DEFAULT zoom := ::nZoom n := hb_bitShift(1, zoom) lon = x / n * 360.0 - 180.0 lat_rad = atan(sinh(PI() * (1 - 2 * y / n))) lat = lat_rad * 180.0 / PI() return {lon,lat} // screen to tile, with decimal, using aTopLeftTileInfo METHOD GetCoordsFromPixel(x,y) class TMapControl LOCAL top := ::aTopLeftTileInfo[1] LOCAL left := ::aTopLeftTileInfo[2] LOCAL sx := ::aTopLeftTileInfo[3] LOCAL sy := ::aTopLeftTileInfo[4] return ::GetCoordsFromTile(sx+(x-left)/256,sy+(y-top)/256) METHOD LButtonDown(nRow, nCol, nKeyFlags, lTouch) class TMapControl ::lastMousePos := {nRow,nCol} return ::Super:LButtonDown( nRow, nCol, nKeyFlags, lTouch ) METHOD RButtonDown(nRow, nCol, nKeyFlags, lTouch) class TMapControl ::lastMousePos := {nRow,nCol} return ::Super:RButtonDown( nRow, nCol, nKeyFlags, lTouch ) METHOD MouseMove( nRow, nCol, nKeyFlags ) class TMapControl LOCAL oldMouseCoords,newMouseCoords if (nKeyFlags<>1 .and. nKeyFlags<>2) .or. empty(::lastMousePos) return 0 endif oldMouseCoords := ::GetCoordsFromPixel(::lastMousePos[2],::lastMousePos[1]) newMouseCoords := ::GetCoordsFromPixel(nCol,nRow) ::nLon += oldMouseCoords[1] - newMouseCoords[1] ::nLat += oldMouseCoords[2] - newMouseCoords[2] ::lastMousePos := {nRow,nCol} ::Refresh() return ::Super:MouseMove( nRow, nCol, nKeyFlags ) METHOD MouseWheel( nKey, nDelta, nXPos, nYPos ) class TMapControl if nDelta>0 .and. ::nZoom<::nMaxZoom ::nZoom+=1 endif if nDelta<0 .and. ::nZoom>0 ::nZoom-=1 endif ::Refresh() return ::Super:MouseWheel( nKey, nDelta, nXPos, nYPos ) METHOD GetImage(x,y,zoom,lQueue) class TMapControl local n, cUrl, img LOCAL oHttp DEFAULT zoom := ::nZoom DEFAULT lQueue := .T. x:=int(x) y:=int(y) // looking for the image in the "cache" n:= aScan(::aImages, {|v| v[2]=zoom .and. v[3]=x .and. v[4]=y }) if n>0 // move the last returned image on top of cache img := ::aImages[n][1] //aDel(::aImages,n) //::aImages[len(::aImages)] := img return img endif if .not. lQueue return nil endif // TODO: Limit cache size cUrl := ::aServers[::nServer] ::nServer++ if ::nServer>len(::aServers) ::nServer:=1 endif cUrl := StrTran(cUrl,"{zoom}", allTrim(str(zoom))) cUrl := StrTran(cUrl,"{x}", allTrim(str(x))) cUrl := StrTran(cUrl,"{y}", allTrim(str(y))) if (n:=aScan(::aHttps, {|v| v[2] = zoom .and. v[3] = x .and. v[4] = y})) > 0 // already in download, update last query time ::aHttps[n,5]:=Seconds() return nil endif begin sequence oHttp := win_oleCreateObject( "Msxml2.XMLHTTP.6.0" ) oHttp:Open("GET", cUrl, .T. ) oHttp:Send() if oHttp:readyState <> 4 if oHttp:readyState=1 .or. oHttp:readyState=3 aAdd(::aHttps,{ oHttp, zoom, x, y, Seconds(), cUrl }) endif else img := GDIP_ImageFromStr(oHttp:ResponseBody(), .t., .f.) if .not. empty(img) aAdd(::aImages, { img, zoom, x, y }) endif endif end sequence return img

In this control is present the method GetCoordsFromPixel that returns {lon,lan}
And you can add put the markers with the method AddMarker.

What is necessary is replace the rendering of the markers

The only thing I ask is if you use it and improve it, share the improvement with the forum

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Get latitude and longitude

Get latitude and longitude

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