Question on Data Clocks Displaying Nulls vs Zeros

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04-17-2024 04:51 PM
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JillClogston
New Contributor III

Hi all, 

I am looking at data on whale sightings, specifically the number of days present in a month. I am creating data clocks for each group of whales.  Some of the month cells with days present equal to zero are indicated by the ≤ 1 color while other months with no sightings are indicated by the null color.

Why would that be?

JillClogston_0-1713397257938.png

I am using ArcGIS Pro 3.2.

Thanks in advance!
Jill

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ChristopherAllen
Esri Contributor

Hi @JillClogston ,

The data clock will display null for cells that are outside the temporal extent of your data. When using a Count aggregation, cells that are within the temporal extent of your data but have no observations will display zero.

Thanks for the question,
Chris

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ChristopherAllen
Esri Contributor

Hi @JillClogston ,

The data clock will display null for cells that are outside the temporal extent of your data. When using a Count aggregation, cells that are within the temporal extent of your data but have no observations will display zero.

Thanks for the question,
Chris

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JillClogston
New Contributor III

Thank you @ChristopherAllen

To clarify, in the data clock I posted above theoretically covers 48 months. However, for this particular group of whales, they were not seen until August of 2019. Does Arc look for the first temporal data point and call that the beginning of the temporal extent, hence the gray cells?

Thanks again!
Jill

ChristopherAllen
Esri Contributor

Hi @JillClogston ,

Thanks for the follow up! You're correct, Pro looks for the first temporal data point and calls that the beginning of the temporal extent and hence the gray cells. 

To clarify, in the data clock I posted above theoretically covers 48 months. However, for this particular group of whales, they were not seen until August of 2019.

When you say the dataset covers 48 months, do you mean that there are dates in the "Date" field that are before August 2019? I just want to make sure you're not encountering a bug! 

Thank you,

Chris