feature for using of self created and calibrated map ( as possible in/with ublox )

[wernerdd]

It would be fine to have a similar feature as with the u-blox-tool ( ubx-User-Guide , chapter 5.2.10.2 Map calibration ).
So you can use the pygpsclient offline or if working with NTRIP one has just low data transfer and no key for online-pas is needed.
So one can use your own scanned map as possible for other GPS-Devises too ( e.g. Garmin, ... look ExperetGPS ).

[semudev2]

Hi @wernerdd

Thanks for the suggestion. Probably wouldn't be that hard to implement - I effectively already do something similar for the World Map display (see https://github.com/semuconsulting/PyGPSClient/blob/master/src/pygpsclient/map_frame.py#L173) and could readily adapt this to larger scale map tiles.

For simplicity sake I'd probably want to add a few provisional caveats:

1. User-supplied map must be a standard WGS84 Web Mercator projection (i.e. lon and lat lines are parallel).
2. User-supplied map must be in png format (user can use an external tool to convert formats).
3. User would provide file path and calibration points via a new 'user map' section in the pygpsclient.json configuration file.

Happy to add it to the feature backlog for implementation as and when I get the time.

[semuadmin]

Hi @wernerdd,

I've added an enhancement which implements basic support for a user-defined custom (offline) map:

The user-defined map can be defined via the following configuration file parameters:

"usermaps_l": [
   [
      "/home/myuser/maps/mymap01.tif",
      [52.48903090029343, 13.376796709434993, 52.428992219505325, 13.513273402895]
   ],
   [
      "/home/myuser/maps/mymap02.tif",
      [52.43227595237385, 13.499564532600285, 52.37215985772205, 13.636041225870589]
   ],
   [
      "/home/myuser/maps/mymap03.tif",
      [52.37776419675291, 13.625147570124257, 52.31757380344052, 13.761624263584265]
   ],
   etc...
]

If the current receiver position is outside the bounds of the map, you'll see an 'OUT OF BOUNDS' warning message.

See the sample pygpsclient.json configuration file. Here's an illustration using a custom geoTIFF image exported from an Open Street Map © tile using QGIS:

[gdt]

It would be nice to support geotiff so you can export a map in qgis and use it, if there is custom map support at all.

[semuadmin]

Could readily support any image file format that can be opened as an PIL.ImageTk.PhotoImage and loaded into a tkinter canvas (including PNG, JPG, GIF, TIFF, WEBP, etc. - the list is dependent on underlying operating system support), but would need some extra work to convert CRS and generate lat/lon bounding box (e.g. using rasterio library).

In the short term you could use something like this to automatically generate the necessary PyGPSClient json config settings for your geoTIFF file:

from rasterio import open as openraster
from rasterio.warp import transform_bounds

files = ["mymap01.tif", "mymap02.tif", "mymap03.tif"]

print('"usermaps_l": [')
for i, fl in enumerate(files):
   fl = fl.strip()
   ras = openraster(fl)
   lonmin, latmin, lonmax, latmax = transform_bounds(ras.crs.to_epsg(), 4326, *ras.bounds)
   print( f'   [\n      "{abspath(fl)}",\n      {[latmax, lonmin, latmin, lonmax]}\n   ]{"," if i < len(files)-1 else ""}')
print("]")

"usermaps_l": [
   [
      "/home/myuser/maps/mymap01.tif",
      [52.48903090029343, 13.376796709434993, 52.428992219505325, 13.513273402895]
   ],
   [
      "/home/myuser/maps/mymap02.tif",
      [52.43227595237385, 13.499564532600285, 52.37215985772205, 13.636041225870589]
   ],
   [
      "/home/myuser/maps/mymap03.tif",
      [52.37776419675291, 13.625147570124257, 52.31757380344052, 13.761624263584265]
   ]
]

[semuadmin]

Basic offline custom map support has been added in pygpsclient>=1.4.11, as described above.

I've added a simple utility georef.py in the \examples folder which can automatically generate the relevant PyGPSClient configuration settings for any supported georeferenced image files e.g. geoTIFF.

I may make automatic geoTIFF import a core function in a future release, but for the time I am keeping this import utility separate as I would prefer to avoid an additional external library dependency (rasterio) for functionality which may only be used infrequently.

Feedback and contributions welcome.