Data Content Frequently Asked Questions



USGS Daily Values (Watstore)

Q: Sometimes, my Daily Data view shows values that are colored blue. Why?
Blue highlighting in the Daily Data view signals that the data are marked as Provisional. A district marks its data as Provisional while it is verifying that the data are correct. Provisional data are subject to change by the district. In theory, once the data are 'promoted' out of the provisional category, the values will not change. However, it is not unusual for the district to revise data even when they are not marked as Provisional.

USGS Peak Values (Watstore)

Q: What's the difference between an Annual Peak and a Partial Peak?
The Annual Peak is the instantaneous maximum flow recorded at a site in a year. A Partial Peak is an instantenous peak flow that exceeds the defined base flow for the station and occurs at a distance in time from other peaks. Thus, if the Annual Peak is greater than the base flow, it is a partial peak as well.

NCDC Summary of the Day (TD-3200)

Q: Sometimes, my Daily Data view shows values that are colored green. Why?
Green highlighting in the Daily Data view signals a precipitation data value that is marked as Accumulated. This means that the observer could not record the precipitation over a period of one or more days, and instead recorded the total amount of precipitation since the last reading. Usually, the missed days are marked in the database as Missing, but this is not always the case.

NCDC Hourly Precipitation Data (TD-3240)

Q: Sometimes, my Hourly Data view shows values that are colored red. Why?
Red highlighting in the Hourly Data view signals a value that has an unmatched flag. Usually, flags are paired, signalling a start and an end to some state. When Hydrodata finds an unmatched flag, it makes no attempt to guess what the station intended - it just marks the value with red. If you find a red value in the Hourly Data view, you should look at the corresponding date in the Event View to see what events occurred around that time. It is up to you to decide how the flags should be interpreted.

NCDC 15-Minute Precipitation Data (TD-3260)

Q: Sometimes, my 15-Minute Data view shows values that are colored red. Why?
Red highlighting in the 15-Minute Data view signals a value that has an unmatched flag. Usually, flags are paired, signalling a start and an end to some state. When Hydrodata finds an unmatched flag, it makes no attempt to guess what the station intended - it just marks the value with red. If you find a red value in the 15-Minute Data view, you should look at the corresponding date in the Event View to see what events occurred around that time. It is up to you to decide how the flags should be interpreted.

GeoSelect EPA STORET Data

Question #1:
Yes or No.


Return to Hydrosphere Home Page
Send suggestions to hdpweb@hydrosphere.com
Last Updated May 22, 1997
Copyright © 1997 Hydrosphere Data Products, Inc.