FIT Write Bug

I don't think there's much to do. This was discussed in the forum in a different context: when the datafield want to indicate that there's no "value" (unknown / invalid / etc..., for example when the external ANT HRM stopped sending valid HR values) Currently what you see is that the last value is "extended" until another value is recorded. It kind of works like "smart recording" when values are not sent every second if the value didn't change. In case datafield crashed it's kind of nice that restarting it continued the same activity. I don't know if my DF could do that or I would need to start a new activity.

I don't think there's much to do. This was discussed in the forum in a different context: when the datafield want to indicate that there's no "value" (unknown / invalid / etc..., for example when the external ANT HRM stopped sending valid HR values) Currently what you see is that the last value is "extended" until another value is recorded. It kind of works like "smart recording" when values are not sent every second if the value didn't change. In case datafield crashed it's kind of nice that restarting it continued the same activity. I don't know if my DF could do that or I would need to start a new activity.

FlowState - ok I've tested this. It doesn't work for me. I've tried FLOAT with 0xFFFFFFFF as the invalid. It just writes "-1". Have you gotten this to work with any data types?

That brings up another question. There are a bunch of data types we can set in the FIT createfield. Using your example, for Effective Wind Speed (relative influence of a head or tailwind), I'd like to use a SIGNED 8-bit Integer. In my code, is there a way to more precisely convert a variable to, say, a Signed 8-bit Integer? Or just sending it a "toNumber()" will work?

WHAT!!!! This is HUGE. THANK YOU. I'll go test that today.

That said - it should be AWESOME if we could write a NULL and the graph doesn't show anything during that time. 

I think you can -- I used to think you couldn't (although obviously native apps can) but if you dig into the FIT protocol spec, there is a special "invalid value" for each data type. For example, for an unsigned 8-bit integer, it's 255. In general, for any given data type, the invalid value is the largest representable positive number.

If you write an invalid value, it should be displayed as "no data".

forums.garmin.com/.../feature-request-enable-ciq-apps-to-indicate-no-data-missing-data-incorrect-data-in-a-fit-field

That said - it should be AWESOME if we could write a NULL and the graph doesn't show anything during that time.