Best Practices for Retrieving Data

Use current data cache files

• Files (in uncompressed and GZipped XML and CSV format) containing the most current worldwide data for METARs, TAFs, Aircraft Reports, and AIR/SIGMETs can be downloaded frequently from:
  
  http://weather.aero/dataserver_current/cache
  or
  http://weather.aero/dataserver1_4/cache
  
  Please visit Current Data Caches for more information.

Use data compression

• Compress data using the "compression=gzip" parameter in your request. This compresses your results and decreases the size of the returned file. XML results compress very well. This is especially relevant for users concerned with bandwidth.


• Gzipped files can usually be viewed directly in your browser. Most browsers will automatically unzip these when they are selected. If not, save the file to your disk and run unzip it manually.

Minimize the number of requests

• For example: when retrieving more than one station, instead of making numerous requests for single stations consider combining these into one request:

Multiple requests:
dataSource=metars&requestType=retrieve&format=xml&hoursBeforeNow=2&stationString=KDEN
dataSource=metars&requestType=retrieve&format=xml&hoursBeforeNow=2&stationString=KMIA
dataSource=metars&requestType=retrieve&format=xml&hoursBeforeNow=2&stationString=KSFO
dataSource=metars&requestType=retrieve&format=xml&hoursBeforeNow=2&stationString=KSLC
dataSource=metars&requestType=retrieve&format=xml&hoursBeforeNow=2&stationString=KLAX
dataSource=metars&requestType=retrieve&format=xml&hoursBeforeNow=2&stationString=PHNL
dataSource=metars&requestType=retrieve&format=xml&hoursBeforeNow=2&stationString=PHTO
dataSource=metars&requestType=retrieve&format=xml&hoursBeforeNow=2&stationString=CYZT
dataSource=metars&requestType=retrieve&format=xml&hoursBeforeNow=2&stationString=KORD
dataSource=metars&requestType=retrieve&format=xml&hoursBeforeNow=2&stationString=CYQB
dataSource=metars&requestType=retrieve&format=xml&hoursBeforeNow=2&stationString=CYLL
...

Single request:
dataSource=metars&requestType=retrieve&format=xml&hoursBeforeNow=2
&stationString=KDEN,KMIA,KSFO,KSLC,KLAX,PHNL,PHTO,CYZT,KORD,CYQB,CYLL, ...  

Don't unecessarily request large amounts of data

• Constraining requests as much as possible improves response time and overall server load. Consider using time, station, and geographic constraints as appropriate to make the query as specific as possible.

Use the constraint version of the MostRecentForEachStation whenever possible

• This is considerably more efficient than the postfilter version, especially when retrieving TAF data. See the 1.2 release notes for details on the difference.