Integrated grid square calculations with GPSd #435

n8jja · 2023-12-12T06:27:04Z

Moved the position checking inside a Goroutine that runs every 5 minutes.
Created updateGridIfNeeded function, it checks the grid location in config.Locator and updates it if necessary.
Expanded the functionality of the GPSd TPV object to include the grid square as one of its values.
Consolidated all functionality for Maidenhead calculations inside GPSd for simplicity.

…e via GPSd automatically every 5 minutes. The package file contains maidenhead.go and maidenhead_tests.go. Additionally, added a new go routine to main which will run the update in the background. The update interval and ability to be tunred on/off have not been implemented yet.

…e via GPSd automatically every 5 minutes. The package file contains maidenhead.go. No test have been written either. Additionally, added a new go routine to main which will run the update in the background. The update interval and ability to be tunred on/off have not been implemented yet.

…oved the maidenhead package. Refactored the grid square update routine in main to use the new function and lock the config file while updating.

…ying the code in main. * Go routine checks the position every 5 minutes. * updateGridIfNeeded will check the grid square in config.Locator and update if required. * GPSd TPV objecrt now includes the gridsquare as one of its values. * GPSd contains all functionality for maidenhead calculations for simplicity.

martinhpedersen · 2023-12-22T05:50:27Z

internal/gpsd/objects.go

+	GridSquare          string `json:"-"`
+}
+
+func (t *TPV) CalculateGridSquare() error {
+	lat, err := t.Lat.Float64()
+	if err != nil {
+		return err
+	}
+
+	lon, err := t.Lon.Float64()
+	if err != nil {
+		return err
+	}
+
+	point := maidenhead.NewPoint(lat, lon)
+	t.GridSquare, err = point.GridSquare()
+	return err


This is no longer needed I believe? conn.GetGridSquare() is not using the TPV's GridSquare, but calculates from LatLon on the fly.

Hi Martin!

You are correct...it is an artifact that I forgot to remove. Thanks!

martinhpedersen

Thanks! I think we're almost there 😄

It appears to me like this PR contains traces of multiple approaches we discussed in the email.

In my mind, this is what we discussed:

Simplest (requires the least changes):

func (p Position) GridSquare() (string, error) {
  return maidenhead.NewPoint(p.Lat, p.Lon).GridSquare()
}

... alternatively add field Position.GridSquare and enrich in func (t TPV) Position() Position ignoring the error.

func (t TPV) Position() Position {
  ...
  // The error is ignored as it's always nil for valid coordinates.
  p.GridSquare, _ := maidenhead.NewPoint(p.Lat, p.Lon).GridSquare()
  return p
}

And finally:

func (c *Conn) NextGridSquare() (string, error) {
  pos, err := c.NextPos()
  if err != nil {
    return "", err
  }
  return maidenhead.NewPoint(lat, lon).GridSquare()
}

The latter is already implemented in this PR, but not used.

Which of the options do you think is best?

In addition I have some concerns regarding the way you persist the updated locator to disk. Please see in-line comments.

internal/gpsd/objects.go

martinhpedersen · 2023-12-22T05:54:44Z

main.go

@@ -214,6 +215,7 @@ func optionsSet() *pflag.FlagSet {
 	set.BoolVarP(&fOptions.SendOnly, "send-only", "s", false, "Download inbound messages later, send only.")
 	set.BoolVarP(&fOptions.RadioOnly, "radio-only", "", false, "Radio Only mode (Winlink Hybrid RMS only).")
 	set.BoolVar(&fOptions.IgnoreBusy, "ignore-busy", false, "Don't wait for clear channel before connecting to a node.")
+	set.BoolVar(&fOptions.UpdateGrid, "gridsquare-update", true, "Automatically update the maidenhead grid square from the gpsd daemon.")


We use the term locator in the config. Maybe not the best term, but I think we should use the same term both places sice the two are very much related.

--locator-from-gpsd maybe?

Hi Martin!

Yes, I will change to align with the existing terminology. It makes the most sense to keep things consistent.

martinhpedersen · 2023-12-22T06:14:46Z

main.go

+		// write config
+		if err := WriteConfig(config, fOptions.ConfigPath); err != nil {
+			log.Printf("Unable to write config: %s", err)
+		}


I don't think rewriting the actual config file is the best idea. It is not a lossless operation, as the user might have defined keys and values that are not part of the JSON spec (e.g. "comments"). Custom formatting will also be lost, and possibly also ordering of aliases etc. It also has the potential of corrupting the file if we for some reason the operation fails in the middle of writing (full disk, power loss++).

I guess it's useful to retain the "last known" position when restarting the app. Otherwise, the user would have to wait the 5 min interval before the locator field is updated again

As I see it, we have two options:

Persist the "last known position" in a separate JSON file, and use that as a initial value (if present).

Block on startup until we get a fresh position from GPSd.

I think the latter might be a better solution, as it guarantees running with --locator-from-gpsd uses a value from GPSd at all times.

Thanks Martin...I agree the latter would be the better option.

After some refreshing on this...won't the gaps.Dial() and conn.NextPos() already blocking?

martinhpedersen · 2023-12-22T06:18:40Z

main.go

+			for range time.Tick(time.Minute * 5) {
+				updateGridIfNeeded()
+			}


What's the reason for polling once per 5 minute? Wouldn't it be even better to continuously keep the locator field up-to-date by subscribing (Watch(true)) and call Next() in an endless loop? 🤔

My thought was that while most people will be mostly static...i.e. once they get the first fix from the GPS, they won't need it anymore. However, for true mobile operation, it might be required to get a new grid square at a regular interval.

I picked 5 minutes at random for testing, but I think long term, this might be something we allow the user to enable/disable and set the interval as needed. If you were in a moving car for example, 5 minutes might be a good interval, but on a sailboat, it might need be only once every few hours.

I'll disable the loop for now.

main.go

martinhpedersen · 2023-12-22T06:21:46Z

internal/gpsd/gpsd.go

@@ -235,3 +243,24 @@ func errUnexpected(err error) error {
 	}
 	return err
 }
+
+// GetGridSquare provides function for getting updated position and calculating the grid square.
+func (c *Conn) GetGridSquare() (string, error) {


I believe NextGridSquare() would be a better name for this, to better harmonize with Next() and NextPos() 🙂

Absolutely!

martinhpedersen · 2023-12-22T06:55:23Z

internal/gpsd/gpsd.go

+type GPSdClient interface {
+	Dial(addr string) (GPSdClient, error)
+	Watch(enable bool)
+	Next() (*TPV, error)
+}
+


This is unused? If so, please omit it 😊

I am looking at storing the Locator in the user.json for the multi-user reloader. Like KM4ACK's user swap by config swap
in the PAT Menu 12. GPSd is great and I have one pi feeding 4 pi's locator. only have a 20 minute gap every other month.
in mailbox/CallSign/user.json is (CALLSIGN, Name, TAC), Locator (EL29ER27), WinLink/user (Password), Roll (Owner, Radio Op, Non-Ham), On Duty(00-23), NTS (routing itu-r2, NOAM, USA, TX, STX,) HW ACCESS (Telnet, Wifi2, Wifi5, Ardop, ### Ax25, VaraHF, VaraFM, VaraSat)
Just have to get the Variables loaded at the right time for each Network http connection session or postoffice push/pull.
This lets windows and mac users to get multi-user.... Roll->Multi-user->PostOffice->NTS
Herbert KD5PQJ

n8jja added 7 commits December 2, 2023 15:47

Added ability to turn on automated updating of grid square via GPSd.

945b1f5

Refactored to include GetGridSquare() within the gpsd package and rem…

eddc339

…oved the maidenhead package. Refactored the grid square update routine in main to use the new function and lock the config file while updating.

Refactored to include GetGridSquare() within the gpsd package and rem…

2b78798

…oved the maidenhead package. Refactored the grid square update routine in main to use the new function and lock the config file while updating.

martinhpedersen changed the base branch from master to develop December 12, 2023 17:34

martinhpedersen self-requested a review December 21, 2023 17:55

martinhpedersen added the enhancement label Dec 21, 2023

martinhpedersen added this to the v0.16.0 milestone Dec 21, 2023

martinhpedersen reviewed Dec 22, 2023

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martinhpedersen requested changes Dec 22, 2023

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martinhpedersen reviewed Dec 22, 2023

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martinhpedersen removed this from the v0.16.0 milestone Apr 13, 2024

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Integrated grid square calculations with GPSd #435

Integrated grid square calculations with GPSd #435

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Integrated grid square calculations with GPSd #435

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Integrated grid square calculations with GPSd #435

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