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November 26th, 2012
The NCEDC is pleased to announce a set of web services that provide new ways for users to query and retrieve information from the NCEDC. These services provide simple functions that can be used from a web browser, command-line programs such as curl and wget, and through programming languages such as perl, python, shell scripts, or MATLAB. The initial set of NCEDC web services provide station and channel information, channel instrument responses, and time series data.
Why web services?
Web services at the NCEDC use a RESTful (Representational State Transfer) design to provide a simple stateless query and data retrieval system. RESTful Web services use the HTTP protocol and normally communicate with clients using TCP port 80, which is the default port used by web servers. Using HTTP and standard web server ports minimizes interference from firewalls, and allows you to use web services anywhere you can use a web browser -- from behind most firewalls, and through web proxies.
New web services:
The NCEDC is initially introducing 5 web services:
The ws-station web service http://www.ncedc.org/ws/station provides access to station metadata in the NCEDC database. The results are returned in XML format using the StationXML schema. Users can query for station metadata by network, station, channel, location, time and other search criteria and request results at multiple levels (station, channel, response).
The ws-resp web service http://www.ncedc.org/ws/resp provides access to channel response information in the SEED RESP format (as used by evalresp). Users can query for channel response by network, station, channel, location and time
The ws-availability web service http://www.ncedc.org/ws/availability returns information about what time series data is available at the NCEDC. Users can query for inventory information by network, station, channel, location, time and other search criteria. Data can be returned in three different formats: ws-bulkdataselect input, ws-dataselect query parameters and XML.
The ws-dataselect web service http://www.ncedc.org/ws/dataselect returns a single channel of time series data in miniSEED format. With this service you specify network, station, location, channel and a time range and the service returns miniSEED. ws-dataselect is part of the ICAB system. Data that it extracts from the NCEDC repositories can be passed to other ICAB services or can be returned directly.
The ws-bulkdataselect web service http://www.ncedc.org/ws/bulkdataselect returns multiple channels of time series data in miniSEED format for specified time ranges. With this service you specify a list of selections composed of network, station, location, channel, start-time and end-time and the service streams back the selected raw waveform data. ws-bulkdataselect can handle very large selections and can be easily driven by command line programs such as wget, curl or similiar utilities.
These web services are designed to be compatible with the equivalently named web services at the IRIS DMC. Please visit the NCEDC Web Services Web Page for a complete list of NCEDC Web services and descriptions.