B4A Class Open Street Map viewer - GPS

Hi,

This b4Xlib contains a custom view (cvMap) which can display Open Street Map.


screenshot.png
View attachment 109081



The tiles are retrieved from the internet and cached in a database. You can add shapes and images on the map.

UI :
- Lat/lng Center of the map
- Zoom Level
- Compass Direction with rotation
- Scale
- Button Menu
- Grid
- Center
- GPS position and bearing

Event :
- ready
- Lat/lng changed
- Zoom Level Changed
- Compass Direction Changed
- Shape Clicked
- Map Clicked
- Center Lat/lng clicked
- Button Menu clicked
- Scale clicked
- Compass Clicked
- GPS Clicked

Tile Server
2 new properties :
This 2 properties are available in the designer or with setter/getter from the cvmap : userAgent, tileServer

Dependencies :
- Core
- SQL
- OKHttpUtils2
- XUI
- XUI views

Other files in the b4xlib :
- coMapUtilities : code module with Types, functions, helpers
- clTileManager : standard class module to load tile from database and/or internet and save them into the database
- clMapShapeCirgle : standard class to draw circle on the map
- clMapShapeLine : standard class to draw line on the map
- clMapShapePolygon : standard class to draw polygon on the map
- clMapShapeImage : standard class to draw image on the map
- layout cvmap.bal and cvmap.bjl
- images for the compass and gps



How to use it :
- Just add the cvMap custom view with the designer
- create sub to handle events if necessary
- set options (lat/lng, zoom.....)

B4A example and B4J example included



spsp
 

Attachments

  • Screenshot_2021-02-21-11-49-10-222_map.b4A.com.jpg
    Screenshot_2021-02-21-11-49-10-222_map.b4A.com.jpg
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  • B4Xmap.zip
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  • B4Xmap.b4xlib
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Last edited:
Click to expand...
I

Indy

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Star-Dust said:
I have adapted a version for b4i. Obviously it would have been much better to recreate everything with B4XPages, but I don't have the time.

PS. I have not reported everything on B4XLib. If I can in the next few days
PS.2. (Hint) Maybe all panel/pane declarations should be changed in B4XView and created panels with XUI.CreatePanel.
Click to expand...

I'd like to try this version but, in an Android project not B4XPages. Can this be adapted for Android as is or do I need to change things?

Thanks
 
Star-Dust

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Indy said:
I'd like to try this version but, in an Android project not B4XPages. Can this be adapted for Android as is or do I need to change things?

Thanks
Click to expand...
In the first post you find the b4a version not b4xpages.
 
TILogistic

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Carlos marin said:
i get error ResponseError. Reason: , Response: Access denied.

View attachment 109729
Click to expand...

Tile Usage Policy

operations.osmfoundation.org operations.osmfoundation.org

Tile servers - OpenStreetMap Wiki

wiki.openstreetmap.org wiki.openstreetmap.org

B4X: 
'Get Tile from internet openstreemap website
public Sub getTileFromInternet(aZ As Int,aX As Int,aY As Int) As ResumableSub
    Dim j As HttpJob
    Dim bmp As B4XBitmap
    Try
        j.Initialize("", Me)
        j.Download($"https://a.tile.openstreetmap.org/${aZ}/${aX}/${aY}.png"$)
        j.GetRequest.SetHeader("User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:85.0) Gecko/20100101 Firefox/85.0")
        Wait For (j) JobDone(j As HttpJob)
        If j.Success Then
            Try
                bmp=j.GetBitmap
            Catch
                Log(LastException.Message)
            End Try
        End If
    Catch
        Log(LastException.Message)
    End Try
    If j.IsInitialized Then
        j.Release
    End If
    Return bmp
End Sub

Change tile server??
 
TILogistic

TILogistic

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changing user agent works fine

j.GetRequest.SetHeader("User-Agent","Mozilla/5.0 (Windows NT 6.1; WOW64; rv:27.0) Gecko/20100101 Firefox/27.0")
' j.GetRequest.SetHeader("User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:85.0) Gecko/20100101 Firefox/85.0")
Click to expand...
 
Star-Dust

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Carlos marin

Carlos marin

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oparra said:

Tile Usage Policy

operations.osmfoundation.org operations.osmfoundation.org

Tile servers - OpenStreetMap Wiki

wiki.openstreetmap.org wiki.openstreetmap.org

B4X: 
'Get Tile from internet openstreemap website
public Sub getTileFromInternet(aZ As Int,aX As Int,aY As Int) As ResumableSub
    Dim j As HttpJob
    Dim bmp As B4XBitmap
    Try
        j.Initialize("", Me)
        j.Download($"https://a.tile.openstreetmap.org/${aZ}/${aX}/${aY}.png"$)
        j.GetRequest.SetHeader("User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:85.0) Gecko/20100101 Firefox/85.0")
        Wait For (j) JobDone(j As HttpJob)
        If j.Success Then
            Try
                bmp=j.GetBitmap
            Catch
                Log(LastException.Message)
            End Try
        End If
    Catch
        Log(LastException.Message)
    End Try
    If j.IsInitialized Then
        j.Release
    End If
    Return bmp
End Sub

Change tile server??
Click to expand...

Thanks for answering, I can't find this sub in the example, I don't know where to put it or where to call it, I don't get exactly where this error comes from
 
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spsp

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Carlos marin said:
Thanks for answering, I can't find this sub in the example, I don't know where to put it or where to call it, I don't get exactly where this error comes from
Click to expand...
Hi,

The user-agent is in the file clMapTileManager.bas line 69 in the b4Xmap.b4Xlib (which is a zip file)

1615911143318.png


I don't know why it is OK in the B4A example and not in the B4J example.
 
S

spsp

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Indy said:
I'd like to try this version but, in an Android project not B4XPages. Can this be adapted for Android as is or do I need to change things?

Thanks
Click to expand...

Hi,

an minimalist B4A example is attached in this post
 

Attachments

  • B4AOnlyMap.zip
    3.3 KB · Views: 542
TILogistic

TILogistic

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spsp said:
Hi,

The user-agent is in the file clMapTileManager.bas line 69 in the b4Xmap.b4Xlib (which is a zip file)

View attachment 109806

I don't know why it is OK in the B4A example and not in the B4J example.
Click to expand...
Read User-Agent;

Technical Usage Requirements
  • Valid HTTP User-Agent identifying application. Faking another app’s User-Agent WILL get you blocked.
  • If known, a valid HTTP Referer.
  • DO NOT send no-cache headers. (“Cache-Control: no-cache”, “Pragma: no-cache” etc.)
  • Cache Tile downloads locally according to HTTP Expiry Header, alternatively a minimum of 7 days.
  • Maximum of 2 download threads. (Unmodified web browsers’ download thread limits are acceptable.)
Click to expand...
 
I

Indy

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spsp said:
Hi,

an minimalist B4A example is attached in this post
Click to expand...
Hi

Thank you for taking the time to put together a minimal project for me, really appreciate it. Unfortunately, when I run this I get a
B4X: 
ResponseError. Reason: , Response: Access denied.

I don't know what's raising that error. Is there something I need to do? I don't appear to get any permission prompt, which looking at your B4XPages version you had.

Thanks
 
S

spsp

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Longtime User
Indy said:
Hi

Thank you for taking the time to put together a minimal project for me, really appreciate it. Unfortunately, when I run this I get a
B4X: 
ResponseError. Reason: , Response: Access denied.

I don't know what's raising that error. Is there something I need to do? I don't appear to get any permission prompt, which looking at your B4XPages version you had.

Thanks
Click to expand...

Hi,

The permission is only for GPS, I don't use it in the minimal example.

Download again in the first post the B4XMap.b4Xlib. I've modified the user-agent. It should be OK

spsp
 
I

Indy

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spsp said:
Hi,

The permission is only for GPS, I don't use it in the minimal example.

Download again in the first post the B4XMap.b4Xlib. I've modified the user-agent. It should be OK

spsp
Click to expand...

Just downloaded the lib again and retried the app - Worked perfectly! Thank you for your help. I should now be in a good position to convert my current app to use OSM instead of Google Maps.

Thanks again.
 
TILogistic

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You could add the option to change the tile server (ServerTile) and user agent (UserAgent) by parameters.

Sample:
j.Download($"${ServerTile}${aZ}/${aX}/${aY}.png"$)

j.GetRequest.SetHeader("User-Agent",$"{UserAgent}"$)

to comply with the restrictions of tile servers.

User Agent: Email or App Name or Package Name.
Server Tile: use one the lista server or other personal : https://wiki.openstreetmap.org/wiki/Tile_servers
 
S

spsp

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oparra said:
You could add the option to change the tile server (ServerTile) and user agent (UserAgent) by parameters.

Sample:
j.Download($"${ServerTile}${aZ}/${aX}/${aY}.png"$)

j.GetRequest.SetHeader("User-Agent",$"{UserAgent}"$)

to comply with the restrictions of tile servers.

User Agent: Email or App Name or Package Name.
Server Tile: use one the lista server or other personal : https://wiki.openstreetmap.org/wiki/Tile_servers
Click to expand...

Hi,

properties userAgent and tileServer added, see post #1

Thank you for your suggestion

spsp
 
I

Indy

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Hi,

Is there a way of reading back the current GPS position? I tried to see if there was a way of using the GPS_LocationChanged (aLocation As Location) event but that doesn't seem to do anything.

B4X: 
Log(aLocation.Latitude)

I'm looking at incorporating the ability to be able to freely move the map (as it does now) and then click a button to put the map back to where I am now (current GPS pos).

Thanks
 
S

spsp

Active Member
Licensed User
Longtime User
Indy said:
Hi,

Is there a way of reading back the current GPS position? I tried to see if there was a way of using the GPS_LocationChanged (aLocation As Location) event but that doesn't seem to do anything.

B4X: 
Log(aLocation.Latitude)

I'm looking at incorporating the ability to be able to freely move the map (as it does now) and then click a button to put the map back to where I am now (current GPS pos).

Thanks
Click to expand...


Hi,

In cvMap , when the property followGPS is set to true, the map is centered and oriented according the GPS. when this property is set to false, you can move the map.

You can set to false/true this property with a button
 
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