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Creating a visual to display the occupancy in a car park


I have a fact table with columns that show the Purchase Start Date & Time of a vehicle entering a car park and another column that shows the Purchase End Date & Time. I have also split these out into Start Date, Start Time, End Date and End Time.

I need to produce a visual that shows the total occupancy over a day, week, month etc, and so I also have a Date and Time dimension table.

I’ve tried bringing these values into a line chart, but with no success, so I would imagine that I need to create a measure of some kind. Any ideas?

I’ve attached some sample data covering two days.

Sample Data.xlsx (24.1 KB)

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Hello @chrisgreenslade,
Even though you didn’t provide us with a pbix file that explains better what u r trying to achieve. i gave it a try and i hope this answers your question.
You can add a calculated column to your fact table to calculate the occupency (difference between end time and start time) if that’s what u mean by occupency.
to calculate this column use the function

DATEDIF ( start date time, end date time, Hour/Minute…)

the 3rd parametrs gives you the possibility to calculate the difference either in Minutes, Hours…
Her’s a PBIX file. Hope that answers the question. if so, please mark this as a solution

I’m unable to see your PBIX file, @HASSAN_BI.

This helps to give me the purchase duration, but I need to be able to visualise the number of cars entering and leaving the car park at any one time. This is what I mean by occupancy.

Hi @chrisgreenslade,
My aplogies !

Sample data.pbix (91.8 KB)


Thanks for the file. What you have calculated is the total time duration for each vehicle that was in the car park that day.

However, what I need to do is work out the number of cars entering and leaving the car park over a period of time. For example, if 30 cars occupy the car park at 09:15 and then 2 were to leave at 09:17, the occupancy would be 28 at this time. A further 7 cars could then enter at 09:19 bringing the occupancy up to 35.

This is what I need to calculate. @Melissa are you or anyone else able to help too?

Hi @chrisgreenslade,

See if this works for you.

I hope this is helpful.

I wonder if I have entered the DAX incorrectly, but I get this error.

It’s a Measure, working example attached.

Sample data.pbix (93.2 KB)

1 Like


I am writing it as a measure, but still getting the same error. Very odd.

Hi @Melissa,

I’m not sure this is a working example. See attached.

Okay I’m on the latest version of PBI, expect it’s related to this thread.

Try again but instead of the && use a comma like below

Occupancy = 
VAR TimeSelection = SELECTEDVALUE( Data_Sample[Purchase Start Date & Time] )

    CALCULATETABLE( Data_Sample,
        REMOVEFILTERS( Data_Sample[Purchase Start Date & Time] ),
        Data_Sample[Purchase Start Date & Time] <= TimeSelection,
        Data_Sample[Purchase End Date & Time] >= TimeSelection

Thank you @Melissa. That now works.

But how can I show this as a line graph over a 24 hour period say? The idea is that I can see a visual trend throughout the day.

I have tried

Occupancy running total =
ALLSELECTED(‘P&D Purchases’[Purchase Start Date & Time]),
ISONORAFTER(‘P&D Purchases’[Purchase Start Date & Time], MAX(‘P&D Purchases’[Purchase Start Date & Time]), DESC)

To see if I can get a running total of the occupancy measure, but with no success. Ideally I need to show a trend over a 24 hour period, week, etc.

Hi @chrisgreenslade,

Few things to keep in mind. First limit the number of questions in a single thread, you can always create a new topic. Furthermore it will be extremely helpful to you if you take some time and create a full mockup model that resambles your actual production file. I can promise you that will lead to more accurate- and quicker responses from forum members.

In your initial request you talked about visualizing these numbers in a line chart and I think this measure will allow you to do just that. Although keep in mind that because no model was provided, no dimensions were used…

  • Create a new report page
  • Select a Line Chart visual
  • Place the ‘P&D Purchases’[Purchase Start Date & Time] field on the Axis
  • and place the Occupancy measure in the Values section.


1 Like

Ok @Melissa.

Thanks for your help. The visual is taking a long time to load and I am not sure it fully answers my question as you have zero occupancy between 18:00 and just after 06:00 the following day. Which is not the case in the sample data.

However, I have accepted it as a partial solution.