B4A Library GoogleMapsExtras

warwound said:

Hi.
There are already some mapping libraries that store their tiles in a database, MBTiles is one such format.
The OSMDroid library also has it's own OSMDroid SQLite format.
Martin.

Click to expand...

• CustomTileProvider
  Events:
  • GetTile (TileX As Int, TileY As Int, Zoom As Int) As Tile
  Fields:
  • NO_TILE As Tile
  Methods:
  • Initialize (EventName As String)
  • IsInitialized As Boolean
• Tile
  Methods:
  • Initialize (Width As Int, Height As Int, Data() As Byte)
  • IsInitialized As Boolean

Sub Process_Globals

End Sub

Sub Globals
   Dim CustomTileProvider1 As CustomTileProvider
  Dim GoogleMap1 As GoogleMap
  Dim MapFragment1 As MapFragment
  Dim MapPanel As Panel
End Sub

Sub Activity_Create(FirstTime As Boolean)
   Activity.LoadLayout("Main")
  If MapFragment1.IsGooglePlayServicesAvailable = False Then
  ToastMessageShow("Google Play services not available.", True)
  Else
  MapFragment1.Initialize("MapFragment1", MapPanel)
  End If
End Sub

Sub MapFragment1_Ready
  Log("MapFragment1_Ready")
  GoogleMap1 = MapFragment1.GetMap
  If GoogleMap1.IsInitialized = False Then
  ToastMessageShow("Error initializing map.", True)
  Else
     '   set the map-type to none
     '   the new CustomTileProvider is not transparent and we do not want to load any of the built in tile sources
     GoogleMap1.MapType=GoogleMap1.MAP_TYPE_NONE

     Dim GoogleMapsExtras1 As GoogleMapsExtras
     Dim TileOverlay1 As TileOverlay
     Dim TileOverlayOptions1 As TileOverlayOptions

     CustomTileProvider1.Initialize("CustomTileProvider1")

     TileOverlayOptions1.Initialize
     TileOverlayOptions1.SetTileProvider(CustomTileProvider1)
     TileOverlay1=GoogleMapsExtras1.AddTileOverlay(GoogleMap1, TileOverlayOptions1)

     Dim Marker1 As Marker
  Marker1=GoogleMap1.AddMarker(52.75619, 0.3980, "Home Sweet Home")
  Dim CameraPosition1 As CameraPosition
  CameraPosition1.Initialize(52.75619, 0.3980, 6)
  GoogleMap1.AnimateCamera(CameraPosition1)
  End If
End Sub

Sub CustomTileProvider1_GetTile(TileX As Int, TileY As Int, Zoom As Int) As Tile
   Log("CustomTileProvider1_GetTile X="&TileX&", Y"&TileY&", Zoom="&Zoom)

   '   http://developer.android.com/reference/com/google/android/gms/maps/model/TileProvider.html
   '   return a Tile, Null or CustomTileProvider1.NO_TILE

'   Dim Tile1 As Tile
'   '   M6SOFT you need to modify the next line with the correct width, height and byte array tile data
'   '   the existing 2 byte array will likely cause an exception
'   Tile1.Initialize(256, 256, Array As Byte(0, 255))
'   Return Tile1

   '   If you do not wish to provide a tile for this tile coordinate, return NO_TILE
   Return CustomTileProvider1.NO_TILE

'   '   If the Tile could not be found at this point in time, Return Null and further requests might be made with an exponential backoff
'   Return Null

End Sub

warwound said:

Do keep this thread updated on your progress - i'm very interested in how well it performs.

Martin.

Click to expand...

M6SOFT said:

This solution works PERFECTLY!

Click to expand...

Status: Currently this library is still being created, and is not yet ready for download

Click to expand...

The attached class allows you to convert coordinates between Lat Lon coordinates and UTM coordinates.
The conversion is done with WGS84 datum. Note that the class code can handle other datums as well.

Click to expand...

warwound said:

Great!
I shall look at integrating the CustomTileProvider and Tile objects into GoogleMapsExtras shortly.

The fact that your generated tiles are cached is good news and must help performance enormously.
The proj4 page states:

It's in an alpha stage of development presumably?

Click to expand...

Have you any experience of the JTS Topology Suite?
Do you know if it can do the conversion of coordinates from different projections?
It looks to me as if it works with 2d cartesian coordinates only and has no support for different project systems - but i could be wrong.
I did try to wrap the JTS Topology Suite into a b4a library a long while back but never had time to complete the project, and these days i have even less free time so it's unlikely i could complete the wrapper anytime soon.
But it looks to be a very comprehensive and useful library.

Click to expand...

b4a has the Geodesic class module available:
By 'other datums' does Erel mean it supports different projection systems?

Click to expand...

If you look here you'll see some java methods that can be used to convert tile numbers to latitude/longitude and vice versa - these are WSG84 conversions i'm sure.
Would these be useful to you or do you already have working methods to convert between tile numbers and WSG84 coordinates?

Click to expand...

You're working with SQLite and spatial data, have you seen the SpatiaLite update to SQLite?
There's more info HERE.
With SpatiaLite you store spatial features in your tables using spatial geometry types and make queries using spatial geometry clauses.
SpatiaLite also supports many different projection systems.

Click to expand...

I have a working SpatiaLite b4a library - let me know if you are interested, also let me know if you'd still like to see the mapsforge library.

Click to expand...

• CustomTileProvider is now part of GoogleMapsExtras, it is no longer a standalone library.
  CustomTileProvider enables you to provide tiles to the map from your b4a code.
  The code sample linked to above is no longer valid, CustomTileProvider no longer raises an event.
  Instead Reflection is used to call a b4a Sub and the b4a Sub returns a Tile object.
  I shall upload a new code example to show how to use the CustomTileProvider.
• GoogleMapExtras SetPadding is a new method:

  This method allows you to define a visible region on the map, to signal to the map that portions of the map around the edges may be obscured, by setting padding on each of the four edges of the map. Map functions will be adapted to the padding. For example, the zoom controls, compass, copyright notices and Google logo will be moved to fit inside the defined region, camera movements will be relative to the center of the visible region, etc.

  Click to expand...

• LatLngBounds has a new property Center.
• LatLngBoundsBuilder is a new object that enables you to easily create a LatLngBounds object from a number of LatLng objects.
• MarkerExtras has new methods: GetRotation, IsFlat, SetAnchor, SetFlat, SetInfoWindowAnchor and SetRotation.
  Please read the official documentation for details of these new methods: https://developers.google.com/maps/...ence/com/google/android/gms/maps/model/Marker
  The MarkerOptions object has also been updated to support these same new methods.
• OnMyLocationButtonClickListener allows you to override the action performed when the MyLocation button is clicked.
  Please read this thread, depending on whether or not you are using the latest version of the Google Play Services library you may find that the MyLocation button is no longer visible.
  Hopefully this will be fixed sooner rather than later.
• Tile - Contains information about a Tile that is returned by a TileProvider.
  The Tile object is currently only of use if you are using the CustomTileProvider object.

jcredk said:

1) Is the library in 1st page the good one to download and especially with the customeTileProvider ?

Click to expand...

jcredk said:

2) One thing not clear for me: I am not interested in cartography but only the capacity to zoom over tiles, so I planned to put "GoogleMap1.MapType=GoogleMap1.MAP_TYPE_NONE"

Click to expand...

jcredk said:

3) But what is unclear is what is the coordinate system?
Is it still lat longs?
What does it mean according to your tiles: does it mean that you have to imagine that level 0 of tiles is a squared tile that represent the full world ?

Click to expand...

Sub Process_Globals
   Dim LastMapCenter As LatLng
   Dim LastMapZoom As Int
End Sub

Sub Globals
  Dim GoogleMap1 As GoogleMap
  Dim MapFragment1 As MapFragment
  Dim MapPanel As Panel
   Dim TileOverlay1 As TileOverlay
End Sub

Sub Activity_Create(FirstTime As Boolean)
   Activity.LoadLayout("Main")
  If MapFragment1.IsGooglePlayServicesAvailable = False Then
  ToastMessageShow("Google Play services not available.", True)
  Else
     If FirstTime Then
       LastMapCenter.Initialize(0, 0)
       LastMapZoom=0
     End If
  MapFragment1.Initialize("MapFragment1", MapPanel)
  End If
End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)
   LastMapCenter=MapFragment1.GetMap.CameraPosition.Target
   LastMapZoom=MapFragment1.GetMap.CameraPosition.Zoom
End Sub

Sub MapFragment1_Ready
  Log("MapFragment1_Ready")
  GoogleMap1 = MapFragment1.GetMap
  If GoogleMap1.IsInitialized = False Then
  ToastMessageShow("Error initializing map.", True)
  Else
     '   set the map-type to none
     '   we do not want to load any of the built in tile sources
     GoogleMap1.MapType=GoogleMap1.MAP_TYPE_NONE
    
     Dim GoogleMapsExtras1 As GoogleMapsExtras
     Dim TileOverlayOptions1 As TileOverlayOptions
     Dim UrlTileProvider1 As UrlTileProvider
    
     '   Url parameters are %1$d tileX, %2$d tileY, %3$d zoom
     '   my panorama tiles are all in a single directory and are named: <zoom>_<tileX>x<tileY>.jpg
    
     UrlTileProvider1.Initialize("http://162.221.184.24/tmp/wormegay_river_nar/%3$d_%1$dx%2$d.jpg", 256, 256)
     TileOverlayOptions1.Initialize
     TileOverlayOptions1.SetTileProvider(UrlTileProvider1)
     TileOverlay1=GoogleMapsExtras1.AddTileOverlay(GoogleMap1, TileOverlayOptions1)
    
     Dim Marker1 As Marker
  Marker1=GoogleMap1.AddMarker(0, 0, "(0, 0)")
  Dim CameraPosition1 As CameraPosition
  CameraPosition1.Initialize(LastMapCenter.Latitude, LastMapCenter.Longitude, LastMapZoom)
  GoogleMap1.AnimateCamera(CameraPosition1)
  End If
End Sub

• Your images are not 360 degree panoramas, ideally you'd be able to prevent map from wrapping at the meridian longitude. I'm sure there's no way to prevent the GoogleMap from wrapping.
• Using an old HTC Desire to test my project i see that the GoogleMap doesn't allow me to go to zoom level 0. Looks like zoom level 3 is the most zoomed out level available.
• I see no way to tell the GoogleMap at which zoom levels tiles exist.
  Keep zooming in on my panorama and at zoom level 8 and higher there are no tiles available.
  Yet you can continue to zoom in but will just see the map background as tiles fail to load.

marcick said:

Again: it seems to me that if I place many markers with the property InfoWindowShown=true only the last one has the infowindows visible.
So it is not possible to have some or all infowindows visible sametime ?
Marco

Click to expand...