Buienradar

What?

Buienradar (http://www.buienradar.be) is tool to predict rainfall in the Benelux (Belgium, The Netherlands and Luxembourg). In 2015 they added a API to give textual feedback for a given location. They predict rainfall for the next 2 hours with 5 minutes interval. The usage is free for non-commercial usage.

How to?

- Enable the module Buienradar (Module > Weather > Buienradar)
Buienradar Settings
- It is very important your location is as accurate as possible given. There are 3 ways to do so
1) Search a city via Google
2) Use the astro info (Setup > Astro and location) already given to DomotiGa
3) Give lat/lon info manually. (WGS84 encoding)

If your exact location is not already in Domotiga, I prefer to set it manually. Following URL will give you the exact coordinates.
- Open http://www.gps-coordinates.net/
Get Coö Buienradar
- tap your city to focus the map nearby and push "Get GPS Coordinates"
- On the map, zoom in; tap on the exact spot of your home
- Read the GPS coordinates on the left. 6 decimals is preferable.

- Select your output type: integer of mm rain / hour.
The API gives always rainfall data as in integer between 0 (no rain) and 255 (very heavy rainfall).

mm rain / pro hour = 10^((integer -109)/32) 

Rainfall Distribution
--> integer will incrementally change with more and more rainfall
--> mm rain / hour is only accurate with medium rainfall.

Therefore the parameter "precision" is added. It specifies the number of digits in the fractional when mm/h rain is selected. For medium rainfall detection, 3 digits is sufficient.

- Number of values:
Buienradar gives 20 predictions for the next 2 hours. For my purpose (see below) then next 3 predictions is enough, but to keep my module generic, up to 20 values are possible... Default value = 4
- Place of time value
Data of Buienradar always contain "integer value| hh:mm". The module retains the first time and put it on the "place of time value".

Example:
- raw data of the webservice, captured @ 14:54

000|14:55 058|15:00 066|15:05 000|15:10 000|15:15 000|15:20 000|15:25 000|15:30 000|15:35 077|15:40 000|15:45 000|15:50 000|15:55 055|16:00 059|16:05 000|16:10 000|16:15 000|16:20 000|16:25 000|16:30 000|16:35 000|16:40 000|16:45 000|16:50 000|16:55 

- Number of values = 4
- Place of time value = 3
- Output:

value1 = rainfall now
value2 = rainfall now + 5'
value3 = time of rainfall now like 14:05
value4 = rainfall now + 10'

Value1 = 0
Value2 = 58
Value3 = 14:55
Value4 = 66

- Base URL = http://gps.buienradar.nl/getrr.php
This option should not be changed. It contains the base URL for the webservice.

- Update frequency. (Default 300 seconds)
This option should not be changed. Buienradar API refreshed every 5 minutes its values.

- Debug
Enable / disable debug logging in the the DomotiGa Debug Log.

Create Module

- Use auto create module (setup > main > auto create devices)
or
- create a device of type "weather" with interface "virtual" and address "Buienradar"
Device Buienradar
- create the values necessary depending on your settings. (By default, 4 values needed).

Use case

In my bedroom, I like to have my window open to get some fresh air. However, by "medium" rainfall, my shutter needs to go down to protect the interior.
Buienradar is very accurate. To limit false positives, I demand 2 consequence rainfall of at least 30 (= integer or 3 mm / h = medium rainfall). My place (lat/lon) is set to 10m accuracy
If Buienradar detects rainfall like described above, my shutter is going down.
If Buienradar stops detecting rainfall for 15', my shutter is going up again.

Of course, Buienradar is a small parts of the shutter regulation. Also wind, time of the day,... play a role whether my shutter is up/down or somewhere in between...

Reference

- http://gratisweerdata.buienrahttp://www.gps-coordinates.net/ dar.nl/
- http://www.buienradar.be
- WGS84: https://nl.wikipedia.org/wiki/WGS_84

BuienradarSettings.png - Buienradar Settings (28.9 KB) johanvandyck, 11/10/2015 02:22 PM

GetCooBuienradar.png - Get Coö Buienradar (620 KB) johanvandyck, 11/10/2015 02:35 PM

RainfallDistribution.png - Rainfall Distribution (14.7 KB) johanvandyck, 11/10/2015 02:53 PM

DevBuienradar.png - Device Buienradar (25.8 KB) johanvandyck, 11/10/2015 03:30 PM

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