HC3 Similarity Forecast automatic access     ("+ Add meteo" Optional)

Last update: Jan. 2018

 

   

    FOR PAY  - Contact us for a quotation

Automatic access to satellite-derived solar radiation database HelioClim-3 Similarity Forecast (data for tomorrow). The Similarity Forecast method explores the HelioClim-3 database to find similar meteorological events in the past in order to make an estimation of the next day irradiation values. We recommend to use this service after sunset today to retrieve the most pertinent data for tomorrow.
Please  for a quotation and receive your SoDa credentials.

Automatic access to HelioClim-3 together Meteo variables is also described ("+Add Meteo" option). Meteo variables are extracted from GFS (NCEP).

Automatic access with WGET - with CURL - Error messages & FAQ - Download examples

Download WGET.EXE

   

 

Warning! It is strongly recommanded to avoid the launch of parallel requests, using the "&" at the end of each wget request line. This would endanger our system.
 

Automatic access with WGET

  1. Subscribe an annual access to HelioClim-3 Similarity Forecast service (Contact us)
  2. Download wget.exe in a directory (on Windows - wget is available by default on Unix)
  3. In the same directory, create a text file and copy-paste in a single line the following instruction to test this permanent access to Carpentras, France, and change the date to tomorrow!:
 

wget -O output.csv --header="soda-user: guest" --header="soda-passwd: guest" ...
"http://www.soda-is.com/pub/hc3v4_similarity_forecast.php?geopoint=44.083,5.059&elevation=-999& ...
firstday=2017-07-29&lastday=2017-07-29&duration=15&time=UT&slope=25&azimuth=180&albedo=0.2&horizon=1&format=unified"

  1. Rename the text file with the .bat extension and double click on it to retrieve the output_HC3-Current-Day_wget.csv output file (Windows environment). Rename the text file with a .sh extension and run it using >my_script.sh in a Unix environment.

  WGET, in details

Request:
wget -O output.csv --header="soda-user: login" --header="soda-passwd: password" ...
"http://server/pub/hc3v4_similarity_forecast.php?geopoint=latitude,longitude&elevation=altitude ...
&firstday=yyyy-mm-dd&lastday=yyyy-mm-dd&duration=time_step&time=time_reference&slope=tilt_of_panels ...
&azimuth=az_of_panels&albedo=ground_albedo&horizon=boolean_horizon
&format=hc3_format&calibration=calib_name"

Inputs:

  • login/password authentication: login and password provided by the SoDa team to access HelioClim-3 within the framework of your subscription. Note that a free permanent automatic access is set up for the site of Carpentras, France, where a Baseline Surface Radiation Network (BSRN) station is available with the login/password guest/guest
  • server: "www.soda-is.com" (main server) or "pro.soda-is.com" (mirror server)
  • latitude and longitude: in degrees, with at least 4 digits after comma
  • altitude: in meters. Set "elevation=-999" to let SoDa get the elevation from Nasa SRTM database
  • yyyy-mm-dd: set the first and the last days of the request. MUST BE SET TO TODAY
  • time_step: "1", "5", "10", "15" (minutes), "h" (hourly), "d" (daily), "m" (monthly)
  • time_reference: "TU" (universal time) or "TST" (True Solar Time)
  • tilt_of_panels: from "0" (horizontal) to "90", or "-999" for tracking. More information on plane orientation conventions in SoDa
  • az_of_panels: from "0" (North), "90" (East), "180" (South) to "270" (West), or "-999" for tracking. More information on plane orientation conventions in SoDa
  • ground_albedo: from "0.0" to "1.0". A usual inland value is "0.2"
  • boolean_horizon: optional. Takes into account "1" or not "0" the shadowing effect due to the far horizon. If not set, default value is "0"
  • hc3_format: optional. The highly recommended value is "unified". If not set, default is the "classic" (deprecated) HC3 format.
  • calib_name: calibration name (default is none). Please refer to the page describing our calibration procedure or/and contact us to ask your questions and receive a quotation.

Outputs: The differences with time series retrieved via the Web interface are:

  • the separator is the space for the "classic" HC3 format and the semi-colon for the "unified" HC3 format.
  • the time period max retrieved using the wget command is: one month for a 1 to 5 min time step, one year for a 10 min up to one hour time step, and unlimited for the other time steps.

"+ Add Meteo" option: The only difference is that by default, the format is unified. Request:
wget -O output.csv --header="soda-user: login" --header="soda-passwd: password" ...
"http://server/pub/hc3v4_meteo_similarity_forecast.php?geopoint=latitude,longitude&elevation=altitude ...
&firstday=yyyy-mm-dd&lastday=yyyy-mm-dd&duration=time_step&time=time_reference&slope=tilt_of_panels ...
&azimuth=az_of_panels&albedo=ground_albedo&horizon=boolean_horizon
"

 

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Automatic access using CURL

You can also automatically retrieve time series using the CURL command. The advantage is two fasten the requests by an approx. factor of 2. Note that all parameters described in the WGET section are valid for CURL, except that CURL outputs don't have any header. Don't forget to set the date for tomorrow!

Request (Windows):
curl -f -s -S -F stations=@stations.txt -o output.csv --header "soda-user: guest" ...
--header "soda-passwd: guest" http://www.soda-is.com/pub/hc3v4_similarity_forecast.php

With the following stations.txt file format:
# Columns:
# id: station name
# latitude and longitude: in degrees, with at least 3 digits after comma
# altitude: in meters. Use -999 to let SoDa get the elevation from Nasa SRTM database.
# time reference: "UT" (universal time) or "TST" (True Solar Time)
# duration: "15" (minutes), "h" (hourly), "d" (daily), "m" (monthly)
# firstday and lastday: first and the last days of the request, expressed as yyyy-mm-dd
# slope of panel: from "0" (horizontal) to "90" (deg). Use -999 for sun tracking.
# azimuth of panel: from 0° (North), 90° (East), 180° (South), ... Use -999 for sun tracking.
# ground_albedo: from "0.0" to "1.0". A usual inland value is "0.2".
# horizon: "0" to ignore relief shadows (default), "1" or "SRTM" for an horizon computed from SRTM
# calibration: calibration name (default is none)
# format: output file format. Possible values are "classic" (default) or "unified" for HC3. The only possible value is "unified" for HC3+METEO
#
#id         lat    lon   elevation time duration firstday   lastday    slope azimuth albedo horizon calibration format
Carpentras 44.083 5.059 -999      UT   15       2018-01-01 2018-01-01 15    180     0.2    1        ""         unified
...

 

"+ Add Meteo" option: The only difference is that by default, the format is unified. Request:
curl -F "stations=@stations.txt" -o output.csv --header "soda-user: guest" --header "soda-passwd: guest" ...
http://www.soda-is.com/pub/hc3v4_meteo_similarity_forecast.php

 

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