StationXML

Read FDSN StationXML-format files describing seismic stations.

The package mostly follows the FDSN schema, with some lesser-used field currently ignored. It should read any schema-compatible StationXML file without error, but bug reports are welcome.

Installation

import Pkg; Pkg.pkg"add https://github.com/anowacki/StationXML.jl"

Use

StationXML is mainly designed to be used by other modules such as Seis to process station information.

Reading FDSN StationXML data

Two unexported functions are available for use in creating FDSNStationXML objects:

StationXML.read(filename): Read from a file on disk.
StationXML.readstring(string): Parse from a String.

For instance (using an example StationXML file supplied with this module):

julia> using StationXML

julia> sxml = StationXML.read(joinpath(dirname(pathof(StationXML)), "..", "data", "JSA.xml"))
StationXML.FDSNStationXML
  source: String "IRIS-DMC"
  sender: String "IRIS-DMC"
  module_name: String "IRIS WEB SERVICE: fdsnws-station | version: 1.1.36"
  module_uri: String "http://service.iris.edu/fdsnws/station/1/query?network=GB&station=JSA&level=response&format=xml&nodata=204"
  created: Dates.DateTime
  network: Array{StationXML.Network}((1,))
  schema_version: String "1.0"

Accessing fields

You should access the fields of FDSNStationXML objects directly. These match the StationXML specification directly, and can also be listed for each of the types with the usual fieldnames(::DataType) function. (E.g., fieldnames(Channel).)

To find out how many stations are in each of the networks returned in your request XML, and what the network code is, you can do:

julia> for net in sxml.network
           println(net.code, ": ", net.total_number_stations, " stations")
       end
BG: 29 stations

To get a vector of the station codes in the one network (GB) returned in our request:

julia> gb = sxml.network[1];

julia> stas = [sta.code for sta in gb.station]
1-element Array{String,1}:
 "JSA"

You can also access individual networks, stations and channels using functions with these names. For example, using the SeisRequests package to get all the broadband, high-gain channels stations in the GB network from 2012 to now:

julia> using SeisRequests, Dates

julia> xml = get_request(
                 FDSNStation(starttime=DateTime(2012), endtime=now(), network="GB",
                             station="*", location="--", channel="BH?",
                             level="channel")).body |> String;

julia> [s.code for s in stations(sxml)]
28-element Array{String,1}:
 "BIGH"
 "CCA1"
 "CLGH"
 "CWF"
 "DRUM"
 "DYA"
 "EDI"
 "EDMD"
 "ELSH"
 "ESK"
 "FOEL"
 "GAL1"
 "HMNX"
 "HPK"
 "HTL"
 "IOMK"
 "JSA"
 "KESW"
 "KPL"
 "LBWR"
 "LMK"
 "LRW"
 "MCH1"
 "SOFL"
 "STNC"
 "SWN1"
 "WACR"
 "WLF1"

Accessor functions

You can easily construct vectors of all the networks, stations and channels in the StationXML using the following accessor functions:

networks(stationxml)
stations(stationxml_or_network)
channels(stationxml_or_network_or_station)

Note that station, for instance, accepts either a Network or a whole FDSNStationXML object, whilst either of those or a Station can be given to channels.

julia> stations(gb)
28-element Array{StationXML.Station,1}:
 StationXML.Station(missing, StationXML.Comment[], "BIGH", 2009-12-15T00:00:00, 2599-12-31T23:59:59, StationXML.RestrictedStatus
  value: String "open"
...

The channel_codes function returns a list of all of the channel codes within a FDSNStationXML document or a Network.

Dot-access to arrays of objects

The module defines getproperty methods for conveniently accessing the fields of each member of arrays of Networks, Stations and Channels. So our previous example of finding all the station codes could actually have been done like this:

julia> stations(sxml).code
28-element Array{String,1}:
 "BIGH"
 "CCA1"
 "CLGH"
 "CWF"
...

We can equally access any other field of the items this way:

julia> channels(sxml).longitude
84-element Array{Float64,1}:
 -3.9087  
 -3.9087  
 -3.9087  
 -5.227299
 -5.227299
 -5.227299
 -6.110599
 -6.110599
 -6.110599
...

Structure of objects

StationXML represents the XML as laid out in the StationXML schema. Therefore, it aims to contain almost all the information which can be contained in a StationXML file. Elements and attributes of the XML are fields within structures nested several layers deep.

lpk-py / StationXML.jl