location coordinates precision

[pdmangel2]

Hi,

I recently stumbled into a issue with geojson coordinate precision : I use a precsion of 8 digits and when I query orion I get a prcision of 6. However the entitity is saved in the mongo DB with a precision of 8.

Is this intended behaviour ?

Kind regards,
Peter

[kzangeli]

Hi there,

yes, it is intended, as for when I render the payload body I have to pick some "decent" number of decimals.
I caould not tell you why I picked 6 though. Guess I "inherited" the 6 from Orion.
Would you like me to change it to 8 ?

[pdmangel2]

Thx for the quick reply, Ken.

1. is this only for coordinates ? Or for all numbers ?
2. Why not return the values as stored in mongo ?
3. If this rerendering is really required, why not make the precision configurable ?

[kzangeli]

1. All floating point numbers
2. Floating point is tricky. Sometimes e.g. 1.9 is stored as 1.899999999999999999999999999999999999999999999 ...
3. Yes quite required - I respond as a JSON and that's a string :) And yes, I could make it configurable

[pdmangel2]

In that case I prefer to have it configurable with 6 as default so the behaviour is backward compatible.

[kzangeli]

That I can do ! :)

[kzangeli]

I'm supposed to make a new release before Saturday next week.
I'll make sure this issue is included before then.

[kzangeli]

Sorry for completely forgetting this issue.
Just stumbled upon it and a PR is imminent. Coming today unless something unexpected happens.
I'm going from 6 to 9 decimals. Non-configurable (turned out to be quite difficult to support configurability).

[kzangeli]

Something unexpected happened.
Modifications in libraries I depend on (FastDDS).
I'm on it, but the PR will NOT be merged today. Sorry ...

[kzangeli]

So, I have a really really bad internet connection right now, but, I believe this issue to be solved finally.
Depending on another, unrelated issue, finally almost fixed, I've merged the pull request of going from a 6 decimal precision to 9 decimals.
I first tried with 12 decimals but that was more than a 64-bit computer could take. E.g. 3.14 was presented as 3.139999999999 ... :(
that's simply not acceptable. With 9 decimals I got acceptable results.

[kzangeli]

So, I have a really really bad internet connection right now, but, I believe this issue to be solved finally.
Depending on another, unrelated issue, finally almost fixed, I've merged the pull request of going from a 6 decimal precision to 9 decimals.
I first tried with 12 decimals but that was more than a 64-bit computer could take. E.g. 3.14 was presented as 3.139999999999 ... :(
that's simply not acceptable. With 9 decimals I got acceptable results.

[pdmangel2]

Thx for the update, Ken. We have a workaround for the time being.
I'll test when released.