# Window duration in seconds with gaps in data

Hi,

I have a table with fuel consumption measurements. The measurements are in liters per hour. Roughly one measurement every 10 seconds. I’m trying to find a way to get a result that shows the total amount of liters consumed in a 10 minute window.

I now have this bit of Flux.

``````from(bucket: "dev_measurements/autogen")
|> range(start: 2020-01-01T00:00:00Z)
|> filter(fn: (r) =>
r.shipId == "71958fc6-194f-4cbb-8b20-52835b77fc64" and
r._measurement == "fuel_consumption" and
r._field == "l/h"
)
|> window(every: 10m)
|> reduce(fn: (r, accumulator) => ({
sum: r._value + accumulator.sum,
count: accumulator.count + 1.0,
}),
identity: {sum: 0.0, count: 0.0}
)
|> group(columns: ["sourceId"])
|> elapsed(unit: 1s, timeColumn: "_start")
|> map(fn: (r) => ({ r with average: r.sum / r.count }))
|> map(fn: (r) => ({ r with absolute: (r.average / 3600.0) * float(v: r.elapsed) }))
``````

This works most of the time as long as there is no gap in the data longer than 10 minutes.

How can I get the duration of the window in seconds without comparing it against the last window? That would make this work correct also when there are gaps in the data I think.

Cheers,
Erik

I solved it by replacing

``````|> elapsed(unit: 1s, timeColumn: "_start")
``````

with

``|> map(fn: (r) => ({ r with elapsed: (uint(v: r._stop) - uint(v: r._start)) / uint(v: 1000000000)}))``