5 ms·

Related to this topic, here's an interesting NOAA site with more details about Earth's magnetic declination and containing lots of data about how it changes spa

Related to this topic, here's an interesting NOAA site with more details about Earth's magnetic declination and containing lots of data about how it changes spatially and temporally: https://ngdc.noaa.gov/geomag/declination.shtml https://ngdc.noaa.gov/geomag/declination.shtml They even have detailed data for predictions about how it is likely to change in the coming years (presently up until the year 2025).

AshamedCaptain 5y ago
> They even have detailed data for predictions about how it is likely to change in the coming years (presently up until the year 2025). They have been publishing the models in 5-year packages for as long as I can remember (e.g. previous one was 2015-2020 model, and so forth). I still have 30 year old devices/PDAs/GPSs that see firmware updates just for the magnetic declination models. Curious how they do it these days, since all these devices with a compass need these up-to-date models. Likely they just phone home every time. :(
- ls65536 5y ago
  It probably depends on the specific application, but I would imagine the models/data that various devices in the field are using are probably updated as part of some periodic maintenance schedule. They don't change significantly enough or quickly enough to demand online updates that frequently, but I suppose every device manufacturer/maintainer has their own way of doing it for whatever reasons they might have. In my own work, I've downloaded the dataset from NOAA and their tools to parse and work with this data to generate my own global 1-degree by 1-degree by 1-year "grid" for magnetic declination [0], along with some code [1] to read this data and be able to give you an estimated value for magnetic declination for any position on the globe for any time instant between 2020 and 2025. Before 2025, I will probably need to download the new data, run the tools again, and update my own dataset (to include values for 2025-2030 or whatever the case may be), but this will definitely be a manual process. [0] https://github.com/ls4096/sailnavsim-core/blob/master/compass_data/mag_dec.csv https://github.com/ls4096/sailnavsim-core/blob/master/compas... [1] https://github.com/ls4096/libproteus/blob/v0.6.2/include/proteus/Compass.h#L60 https://github.com/ls4096/libproteus/blob/v0.6.2/include/pro...

AshamedCaptain 5y ago

> They even have detailed data for predictions about how it is likely to change in the coming years (presently up until the year 2025). They have been publishing the models in 5-year packages for as long as I can remember (e.g. previous one was 2015-2020 model, and so forth). I still have 30 year old devices/PDAs/GPSs that see firmware updates just for the magnetic declination models. Curious how they do it these days, since all these devices with a compass need these up-to-date models. Likely they just phone home every time. :(

ls65536 5y ago
It probably depends on the specific application, but I would imagine the models/data that various devices in the field are using are probably updated as part of some periodic maintenance schedule. They don't change significantly enough or quickly enough to demand online updates that frequently, but I suppose every device manufacturer/maintainer has their own way of doing it for whatever reasons they might have. In my own work, I've downloaded the dataset from NOAA and their tools to parse and work with this data to generate my own global 1-degree by 1-degree by 1-year "grid" for magnetic declination [0], along with some code [1] to read this data and be able to give you an estimated value for magnetic declination for any position on the globe for any time instant between 2020 and 2025. Before 2025, I will probably need to download the new data, run the tools again, and update my own dataset (to include values for 2025-2030 or whatever the case may be), but this will definitely be a manual process. [0] https://github.com/ls4096/sailnavsim-core/blob/master/compass_data/mag_dec.csv https://github.com/ls4096/sailnavsim-core/blob/master/compas... [1] https://github.com/ls4096/libproteus/blob/v0.6.2/include/proteus/Compass.h#L60 https://github.com/ls4096/libproteus/blob/v0.6.2/include/pro...