More of an annoyance so far, but could be serious for an unprepared tramping noob in bad weather.
A few times I have lost twenty minutes or so while detouring around fallen trees because the blue arrow told me I was pointed a different way to the way I was actually pointed.
It was pretty confusing until I realised what was going on. It’s a bit of a niggle to have to check another app or a compass to figure out how to navigate back to the line. (In the forest on an overcast day–most days, here–in places where I can’t see ridge slopes or mapped streams to orient me, it can be difficult to tell which way is which.)
The same delay has happened where the line setters have been a bit economical with marker triangles, and the track has got overgrown or goes through a open-looking section with very little understory. I’ve been caught a few times because I assume a straight-ish line but there’s actually a bend in the line.)
NZ Topo50-North Island and Topo GPS don’t have this problem, matching the compass very well. I’d rather not have to use them or the compass as well as the Trap NZ map, though.
The app shows position and position uncertainty fairly well, although it seems slower to update position and more “jumpy” than the two apps above. It’s just the orientation that’s out, by forty to eighty degrees CW mostly (but sometimes CCW, and sometimes 180 degrees), and unresponsive when I rotate myself.
There is a tradeoff between battery usage and app updates. The app will not respond to location updates if there is no significant position change. For most trappers, battery performance is the highest priority and the app is tuned that way.
iOS is a little problematic in this aspect, but we can take another look at it.
If not already, I would recommend recording a track when in challenging or unknown terrain. You can of course delete it immediately afterwards, but it provides ‘almost’ immediate direction detail, plus allows you to convert the track into a Point of Interest, and then a Line, or simply share your route (email or other,) which might be very useful in a health and safety situation.
Hi Andy! Thanks for the reply. The location updating is fine–I understand the compromises.
It’s the direction indicating arrow that’s the problem. I was out yesterday, and it’s actually worse than I thought. If it can’t be fixed, then please remove the arrow entirely. That would be better than what we have now. It’s better to have no information than misleading information.
I’ve only tested indoors so far - I’ve been a bit tired after work.
When pointing due north the compass app on the phone correctly reports due north (matches my Apple watch and Silva compasses), but Trap NZ reports 337 to 341 degrees. It takes a few seconds to settle. The blue arrow on the location marker marker ring points due north.
Pointing due east, Trap NZ reports 067 degrees, but the arrow on the location marker stays pointing due north. Tapping the “locate” button briefly changes it to about 67 degrees (ENE) but then it jumps back to north.
Pointing due west, Trap NZ reports 236 or 241 degrees and the blue arrow points southwest, approx 240 degrees. As before, tapping the locate button returns the arrow to pointing north. The arrow seems to really like pointing north.
This is in Hawera, magnetic declination about 22.5 degrees East of grid north according to my topoNZ map.
Please let me know if you need more tests. Thanks!
The app reports what the phone hardware reports. Testing here on the iPhone 15 and Galaxy S22 shows the same reading from all compass enable apps including Trap.nz.
There is a bug where it points north briefly when a coord is received from the GPS. I think you are seeing this. A fix on its way for that.
Otherwise it sounds like it’s doing what it should.
Is there some parameter in the read_gps function that controls whether you get orientation relative to magnetic north versus true north, or another specifying how to transform the GPS reading to the map projection used? If there is/are, it’s possible that there are different defaults on different hardware.
As far as the display goes, for me the orientation arrow spends most of its time pointing map north, and only points other directions for a quarter of a second or so - and those directions are wrong.
So can we have a setting to turn off the orientation arrow?