Prefix fields
Most protocols to store data support the prefix field. This field allows you to configure a structure by which data will be organised on the storage provider. Depending on the underlying storage technology, this will either reflect as a folder structure, or as a prefix for file IDs for a virtual folder implementation.
The structure is hidden from the FarEarth *user and is only important if you were to inspect the files directly on the datastore
General fields
The following fields can be used in the prefix. Some fields have a variant which uses zero-padding to allow for fixed length fields.
| Field | Example | Details |
|---|---|---|
productId or id | metopa_68198_20191211T015827 | Product ID given by the processors in FarEarth |
userId | test-at-gmail-com | A modified version of the user ID (e-mail address, e.g., test@gmail.com) |
storeDataId | 628 | Unique ID of the product in the current datastore |
dataStoreId | filesystem-metop-archive | Name of the current datastore |
subscription | farearth | Name of the FarEarth subscription of the archive |
spacecraft | METOP-C | Name of the spacecraft (source of imagery) |
uuid or guid | f567252a-77b9-11ee-b962-0242ac120002 | Randomly generated unique ID |
year | 2025 | The year taken from datetime property of the product |
doy doyPad | 1 ... 365, 001 ... 365 (zero-padded) | The day-of-year number taken from datetime property of the product |
month monthPad | 1 ... 12, 01 ... 12 (zero-padded) | The month number taken from datetime property of the product |
day dayPad | 1 ... 31, 01 ... 31 (zero-padded) | The day-of-month number taken from datetime property of the product |
woy woyPad | 1 ... 52, 01 ... 51 (zero-padded) | The weak-of-year number taken from datetime property of the product |
hours hoursPad | 0 ... 23, 01 ... 23 (zero-padded) | The hour-of-day number taken from datetime property of the product |
minutes minutesPad | 0 ... 59, 01 ... 59 (zero-padded) | The minutes-of-hour number taken from datetime property of the product |
seconds secondsPad | 0 ... 59, 01 ... 59 (zero-padded) | The seconds-of-minute number taken from datetime property of the product |
iso isoSafe | 2025-06-04T03:29:44Z, 20250604T032944T | ISO-8601 formatted date-time string, taken from datetime property of the product. The "Safe" variant removes non-alphanumeric characters for use with filesystems |
version | 0, 1, etc. | Automatically incremented version number if FarEarth detects duplicate products in the Catalogue |
Explicit date-time field variants
The datetime property of the product will be the acquisition time of the product, typically at the start of the interval. You can also use explicit variants for the start or end of the interval, or the processed date. This is achieved with a prefix of start_datetime., end_datetime. or processed_datetime. on any of the date and time fields.
Examples:
start_datetime.monthrefers to the month value at the start of the intervalend_datetime.dayPadrefers to the zero-padded variant of the day value at the end of the intervalprocessed_datetime.isorefers to the ISO-8601 representation of the processed date
The following fields support the explicit variants:
yeardoyanddoyPadmonthandmonthPaddayanddayPadwoyandwoyPadhoursandhoursPadminutesandminutesPadsecondsandsecondsPadisoandisoSafe