4 Tips to Level Up Your Date and Time Data

Date and time data are essential for analyzing patterns and events over time. Understanding how ArcGIS Online stores and displays dates and times is key, whether you’re tracking population changes, weather events, or just need to be on time. In this article, we’ll explore field types and settings that give you more control over your how your date and time data displays across ArcGIS Online.

• Tip #1: Choose the Right Fields
• Tip #2: Set the Web Map Time Zone
• Tip #3: Preserve the Time Zone of the Data
• Tip #4: Adjust for Daylight Savings Time

Making Sense of Time in ArcGIS Online

Here are some universal truths to keep in mind when using a standard Date field in ArcGIS:

• Date and time values are stored in UTC.
• If no time is entered, a default time of 12:00 AM (midnight) is automatically assigned.
• Values shown in popups and tables get adjusted to the viewer’s device time zone.

Glossary

• Device time- the time zone of the device on which you are reading this article.
• DST- Daylight savings time
• UTC – Coordinated Universal Time, or UTC, is the time standard used across the globe. It is effectively Greenwich Mean Time (GMT).

Together, these practices make sure that ArcGIS Online displays event times in your local time zone. For example, imagine there’s an earthquake in a distant location at a specific time. The date field in ArcGIS Online automatically adjusts to show you what time it was in your own time zone when the event happened. That’s pretty handy, at times.

But it can also lead to surprises. Let’s say you enter a date of January 1, 2024, in New York. If you don’t specify a time, it defaults to 12:00 AM in New York. Now, here’s where things get interesting: if someone else views that same record from the Mountain time zone, it shows up as 10:00 PM on December 31st. So, if someone is filtering data by date or year, that event might not even show up in their results because of the principles we outlined above.

In the next sections, we’ll share tips to help you avoid these kinds of surprises.

Tip #1: Choose the right fields

There are four different date and time field types in ArcGIS. Choose the right one based on your needs:

• Date: Stores both date and time together. Always.
• Date only: Stores dates without times, ideal when time is irrelevant.
• Time only: Stores times without dates, useful for schedules and business hours.
• Timestamp offset: Stores date, time, and the time zone offset from UTC, great for data collected across multiple time zones.

For more information on when to use each field type, check out the article New Field Types in ArcGIS Online.

Tip #2: Set the web map time zone

To set a time zone in the Map properties in Map Viewer, you can choose from the following options:

1. Device time zone: The date and time values are adjusted based on each viewer’s device.
2. Specific time zone: The values display in a specified time zone regardless of device time.
3. Data’s time zone: Displays the date and time as-is, without adjusting for device location. Pro tip: If the layer has a time zone set on it (see tip #3), that will persist under this setting.

Setting the time zone for the map gives you more control over how date and time values are displayed in different places. For a deeper dive into web map time zones, check out this article.

Tip #3: Preserve the Time Zone

Time zone information can be preserved in a couple of ways:

• Set it at the layer level when publishing data.
• Set it the feature level using the Timestamp offset field.

Layer level

At publishing time, you can set a time zone for the layer. This is ideal when A) all of the data was collected in the same time zone, and B) you want to preserve the time zone information with the layer. Note: If you don’t specify a time zone at publishing time, it defaults to UTC.

Feature level

Different time zones can be saved for different features using the Timestamp offset field. This is especially useful for global data sets since you can set the date, time, and time zone separately for each feature.

Tip #4: Adjust for Daylight Savings Time

When publishing a layer from ArcGIS Pro, you can adjust for daylight savings time (DST). With the setting enabled, the date and time values are automatically adjusted, forward or back, based on when daylight savings time starts or ends.

Strategies for locking down date and time values

Example 1: Use the right field type

Problem: Let’s say you’re using a standard Date field. If a data collector enters a date, but no time, a default time value of midnight is added. That’s because Date fields always store both a date and a time.

Solution: If only the date is important, use a Date only field.

Example 2: Prevent date time adjustments

Problem: You want date and time values to remain as is, rather than adjust based on the viewer’s device time. For example, a value entered as 1/1/2023 12:00 am viewed on a device in a time zone 1 hour behind is displayed as 12/31/2022 11:00 pm.

Solution: Set the web map time zone to the Data’s time zone so dates and times display consistently across devices.

Pro tip: To ensure that the dates and times remain static when they’re viewed in other places like other maps, the data tab, or ArcGIS Pro, add and calculate Date only and Time only fields. Check out this article for a step by step guide.

Summary

In this article, we explored universal truths and data management strategies to help you level up your date and time data management powers in ArcGIS Online. You can choose from diffferent approaches based on your data needs and goals. Mapping and editing temporal data can be tricky, but having the right understanding and helpful tools can make it easier. By leveraging features such as field types, web map time zones, and layer publishing options, you can gain greater control over how dates and times are stored and displayed across ArcGIS Online.

ArcGIS Online Help has a wealth of information on working with date and time data. And be sure to join the conversation on Esri Community where you can ask questions, connect with other ArcGIS Users and share your own insights.