8/25/09–All items published to ArcGIS Online contain information on when they were published. You can use this information in your searches to find items published during a given time frame.
The date and time an item is published is not stored in a form that is easily read by people. Instead, ArcGIS Online uses UNIX time (also UNIX epoch and POSIX time) as its reference system. UNIX time is defined as the number of seconds that have elapsed since midnight January 1, 1970. So in order to create a search expression that incorporates time, you need to convert time as we typically refer to it (e.g., August 6, 2009 08:40 AM) into UNIX time. Here’s a useful web site that does just that: http://www.epochconverter.com/.
Suppose you want to find all public items published between August 1, 2009, 12:00AM to today (August 6, 2009 08:40AM). First you’d need to convert both of these dates into UNIX time.
August 1, 2009 12:00AM converts to: 1249084800
August 6, 2009 08:40AM converts to: 1249548000
ArcGIS Online actually stores time in milliseconds, so you need to add three zeros to the end of the numbers above. Additionally, you need to pad six zeros on the front of the number. This is because the number is stored as a string in the database.
To form the search expression that you can enter into the search box of ArcGIS Online, you specify you want to search the uploaded field. This is the field that stores the date and time an item is uploaded. Thus, the expression would look like this:
uploaded: [0000001249084800000 TO 0000001249548000000]
Note that the operator TO needs to be in uppercase.
In my case, ArcGIS Online returned a few items dated July 31, 2009. Initially, I was a bit confused by this, but then I realized that time zone differences come in to play. August 1, 2009 12:00AM (UTC – Coordinated Universal Time) is actually July 31, 2009 04:00PM (UTC-8 – Pacific Time).
You can combine the uploaded field with other search parameters. For example:
- earthquakes uploaded: [0000001249084800000 TO 0000001249548000000] – would find items that contain the word earthquakes published in the time frame.
- owner:esri uploaded: [0000001249084800000 TO 0000001249548000000] – would find items owned by ESRI published in the time frame. (NOTE: There are no published items during this time frame from ESRI.)
For additional information on other searchable fields, see http://www.arcgisonline.com/help/content/search/advanced_search.htm
Contributed by Mike Minami of the ArcGIS Online development team