It should not be that incorrect if the tipping gauge is mounted in the correct 
manner. They are not that bad – seriously.

Sent from my Windows 10 phone

From: TheChoctlab
Sent: 19 September 2017 08:36
To: weewx-user
Subject: [weewx-user] Re: Rain gauge errors

Andrew,

In this case, "manipulate" = "correct."

Unfortunately, the difference between what the tipping bucket and the manual 
gauge reads is not linear.  So, multiplying readings by a constant number will 
not work.  I likely will have to make the correction(s) after every day that it 
rains.


On Monday, September 18, 2017 at 8:47:22 PM UTC-7, Andrew Milner wrote:
I forgot to add
1. Take a copy of the database before manipulating/updating values
2. If you 'correct' the readings MAKE A NOTE OF THE DATE TO WHICH YOU DID THE 
UPDATE and then on subsequent manipulations it would be

UPDATE archive SET rain = rain * 2 WHERE dateTime > xxxxxxxxx;

On Tuesday, 19 September 2017 06:43:46 UTC+3, Andrew Milner wrote:
Depends what you mean by 'manipulate'!!

If you have a formula that would convert VP2 reading to match manual reading 
then the formula could be put into the calibration section of weewx.

If you want to change existing readings already in the database then you can 
use SQLite to issue sql statements direcly
eg to double all rain readings before epochdate xxxxxxxxx would be something 
like:

UPDATE archive SET rain = rain * 2 WHERE dateTime < xxxxxxxxx;

On Tuesday, 19 September 2017 06:02:13 UTC+3, TheChoctlab wrote:
My VP2 rain gauge, not unlike other tipping bucket gauges, is often inaccurate. 
I have a Stratus RG202 manual gauge to compare it to.

I understand that I will need to manipulate weewx.sdb to reflect the readings 
from the manual gauge.  But, I am not sure what exactly to manipulate.


Guidance please.
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