osm_pi - OpenSeaMap plugin for OpenCPN

[globalkeith]

Ok before you get too excited I've only made a stub project, this is my first attempt at OpenCPN plugin and my C++ knowledge is weak.

Here is the general idea:

OpenSeaMap is basically a set of tags inside the OpenStreetMap database. There are various tools already available for creating seamarks - and a growing data set. This is the wikipedia of seamarks. I believe a plugin enabling integration with this database will be a great addition.

1. Implement basic plugin structure*
2. Establish getting lat/lon bounds from OpenCPN view
3. Implement API calls to retrieve OSM data**
4. Implement a local data store***
5. Implement API calls to retrieve change sets (new or changes to data based on date)
6. Implement plugin UI to specify data types
7. Implement plugin UI to support API authentication to OpenStreetMap
8. Implement UI to add/edit/update seamark data

* I tried with demo_pi but couldn't get it working, so now I'm trying again with survey_pi
** the Overpass API supports requests for specific bounds and tags (all OSM data is tagged with various "seamark:" tags relating to S57 data types)
*** the survey_pi from Pavel uses spatialite (sqlite) database - which sounds like a great place to start

---

The repo is here: https://github.com/ktec/osm_pi


Please let me know if anyone else is already working on something like this, and if anyone is interested in helping me, just fork the project and send me pull requests, I would be hugely grateful!

[idpnd]

Sounds exciting, also as a shared repository for cruising info

[globalkeith]

Ok, getting pretty frustrated now - I've tried from 3 sources (demo_pi, wmm_pi and survey_pi) to create my own "empty" plugin, with nothing more than an icon, and relevant plugin handlers - still getting no where. While its compiling as part of the main build, and installing to the correct location, despite my best efforts when I run OpenCPN there's no sign of my plugin in the preferences panel.

If someone who knows about these things could take a look at:

https://github.com/ktec/osm_pi

And point out what I'm missing I would be very grateful

thanks
Keith

[globalkeith]

1. Implement basic plugin structure*
2. Establish getting lat/lon bounds from OpenCPN view
3. Implement API calls to retrieve OSM data**
4. Implement a local data store***
5. Implement API calls to retrieve change sets (new or changes to data based on date)
6. Implement plugin UI to specify data types
7. Implement plugin UI to support API authentication to OpenStreetMap
8. Implement UI to add/edit/update seamark data

[bdbcat]

globalkeith....

What does OpenCPN logfile say?

What version of OpenCPN are you working with?

Dave

[bdbcat]

Keith....

Are you on Windows or linux?

If linux, put some printf in the PlugIn code, especially to see if the ::Init() call is made.

int osm_pi::Init(void){
  printf("OSM Init call\n");
  ::wxBell();                       // ring the bell

      m_lat = 999.0;
      m_lon = 999.0;
      AddLocaleCatalog( _T("opencpn-osm_pi") );


      // Set some default private member parameters
      m_osm_dialog_x = 0;
      m_osm_dialog_y = 0;


      ::wxDisplaySize(&m_display_width, &m_display_height);


      //    Get a pointer to the opencpn display canvas, to use as a parent for the POI Manager dialog
      m_parent_window = GetOCPNCanvasWindow();


      //    Get a pointer to the opencpn configuration object
      m_pconfig = GetOCPNConfigObject();

Dave

[globalkeith]

Hi Dave,

Pavel already helped me get this resolved this morning.

Now trying to:

2. Establish getting lat/lon bounds from OpenCPN view

I've managed to register for cursor lat/lon events using "WANTS_CURSOR_LATLON" and write this to the log, but I'm actually looking for something else.

I want to be able to get the bounds of the screen, so something like

min_lat, min_lon, max_lat, max_lon

Any ideas? I've searched through the existing plugins but not found anything just yet.

thanks
Keith

I'm on linux btw...

[nohal]

Keith...
WANTS_ONPAINT_VIEWPORT & https://github.com/nohal/OpenCPN/blob/cppcheck/include/ocpn_plugin.h#L397 & https://github.com/nohal/OpenCPN/blo...n_plugin.h#L97 (sample usage in https://github.com/nohal/gecomapi_pi)
Or do you want to create it as an overlay? Then have a look at survey, grib or kml plugin code. Or implement it as a custom chart type? No sample code available for this, but BSB4 and NV plugins use it.

Pavel

[globalkeith]

Pavel,

Right now I'm just looking to get the bounds of the view port to make my API calls - however your comments raise some good options.

Once I get data back from I'll want to paint:

- what are the benefits of using either custom chart type or overlay?
- what factors should I consider when making this choice?

[globalkeith]

Ok great, thanks Pavel, I'll pulling off these:

vp.lat_max, vp.lat_min, vp.lon_max, vp.lon_min

But i'm getting values like this:

-1474451447,1078553508,-1895027811,1078479710

Sorry if this is a dumb question but what kind of processing do I need to get this into decimal degress? Do I just /60/60 or something?

[nohal]

Keith...
https://github.com/nohal/gecomapi_pi...pi_pi.cpp#L287 - they are doubles representing degrees, no calculation needed. Are you sure your logic is right? If you push the code to github, I will have a look...

Pavel

[globalkeith]

Thanks Pavel, My bad, it was just that i was using "%d" in my LogMessage, thats why!!

[globalkeith]

I need write code to start download and parse an xml file. Looking at survey_pi its using TinyXml package and looking at the chartdldr_pi its using a httpbuilder.cpp library. Are these good options, or should I consider something else?

[nohal]

Keith...
TinyXml is used everywhere in OpenCPN - very stable, very simple, very very fast. If you don't need a validating parser, it's your choice.
httpbuilder. Well, it's actually the reason for chartdldr_pi not being finished - I was unable to make it reliably work in multiple threads on all platforms with the same codebase. But it's pretty possible that the reason is I was doing something wrong, as me, C++ and multithreading are not kind of friends. But otherwise it was not that bad to use and I didn't find (actually didn't look for) anything better. You may try wxCode - wxCURL

Pavel

[globalkeith]

Ok so wxCurl sounds like a good option, however when trying to build I get an error about wxST_ELLIPSIZE_MIDDLE (not present in 2.8 wxW versions)

For wxCURL 1.0 I need wxW 2.9

What are the implications of this? What version does OpenCPN currently depend upon?

Also, if I decide to use this library, how should I proceed - do I compile and then add something to my plugin header file, or do i need to include the wxCurl source with the plugin?

(sorry little out of my depth here without examples to follow)

Keith