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I believe that I am the one that first introduced the Irrigation Index and found the Watering Index 7 or 8 years ago.



Background...

I started by inventing my own Irrigation Index. It's based on the assumption that people irrigate on a 7 day cycle. Basically, it's the sum of the last 7 days' daily evapotranspirations (ETs) minus the sum pf the last 7 days' rain (both in the same units, I'm in the USA and used inches). If it's positive, that's about how much water  you should put in the next 7 days. It's especially useflu for someone manually irrigating, or using an old controller. Ours is 25 years old.

Then I learned that the California Department of Water Resources (DWR) had published their Watering Index. It needs the highest annual 7 day average ET sum for the locale in question, and also uses the 7 day ET sum. Divide the 7 day sum by the high average and express it as a percent. That's the percentage you should set a properly adjusted modern controller to for the next week.

I then modified the DWR's index by subtracting out the 7 day rain from the 7 day ET before dividing, giving what I think is a more useful percentage.

The main issue with the DWR index is finding the high 7 day ET for a given area. If you can't find it, you could estimate it (around here I'd start at at least an inch a week, ours is 1.45") and refine the number as time goes on.

I did include these calcs in another script I wrote to calculate some other fire weather indexes, but is based on a VWS text file that is uploaded to the server. I just looked at the script and it is, unfortunately, way not publishable. :(

Still, this is a teachable/learnable moment. If I figured out how to, in my hacky way, get it done in PHP, anyone else can. All of the math is here. I don't even use a database. The PHP script uses the VWS uploaded text file and saved data in a separate text file from yesterday. Today's calcs are written over the saved data file for tomorrow's run. A cron job calls the script once a day just after midnight.

Awesome, thank you! This is helpful! I thought about trying to create my own in php so maybe i'll go down that road myself. I'm still no expert in PHP but hey, I need an excuse to get better :)

Thanks!
Eric
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I believe that I am the one that first introduced the Irrigation Index and found the Watering Index 7 or 8 years ago.



Background...

I started by inventing my own Irrigation Index. It's based on the assumption that people irrigate on a 7 day cycle. Basically, it's the sum of the last 7 days' daily evapotranspirations (ETs) minus the sum pf the last 7 days' rain (both in the same units, I'm in the USA and used inches). If it's positive, that's about how much water  you should put in the next 7 days. It's especially useflu for someone manually irrigating, or using an old controller. Ours is 25 years old.

Then I learned that the California Department of Water Resources (DWR) had published their Watering Index. It needs the highest annual 7 day average ET sum for the locale in question, and also uses the 7 day ET sum. Divide the 7 day sum by the high average and express it as a percent. That's the percentage you should set a properly adjusted modern controller to for the next week.

I then modified the DWR's index by subtracting out the 7 day rain from the 7 day ET before dividing, giving what I think is a more useful percentage.

The main issue with the DWR index is finding the high 7 day ET for a given area. If you can't find it, you could estimate it (around here I'd start at at least an inch a week, ours is 1.45") and refine the number as time goes on.

I did include these calcs in another script I wrote to calculate some other fire weather indexes, but is based on a VWS text file that is uploaded to the server. I just looked at the script and it is, unfortunately, way not publishable. :(

Still, this is a teachable/learnable moment. If I figured out how to, in my hacky way, get it done in PHP, anyone else can. All of the math is here. I don't even use a database. The PHP script uses the VWS uploaded text file and saved data in a separate text file from yesterday. Today's calcs are written over the saved data file for tomorrow's run. A cron job calls the script once a day just after midnight.
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Weather Display / Re: Soil Temps from Metar? Is it possible?
« Last post by CW2274 on Today at 02:54:08 PM »
Ground conditions can be had from NOTAMS.  Things like inches of snow, water, etc.
NOTAMS (Notice to Airmen), are for telling flight crews of anomalies or outages for the complete phase of flight, from chock to chock, i.e. closed runways and/or taxiways, NAVAID outages, construction near runways, ect.
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For instance, temperature reads 44, dewpoint reports 32 with an error of +8.
On the same day, the humidity high reading was 84%, even though it was drippy all day.

What can I check on the unit to see if there's a way to fix humidity/dewpoint errors?


Disregarding (for the moment) CWOP .....  I suggest that you find out whether your station is measuring the dew point/humidity properly.  To do that, you'll have to borrow (or purchase) another measuring device, and measure the humidity (several different hours) at the same location as your station.  It's very important to do that very near your station.  And don't expect exact agreement - just close.

Note: Amazon has psychrometers available for less than $30.00

If your station is measuring correctly, then ignore CWOP.  Otherwise, ask here.  In any case, please let us know the results.
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i'll check line by line with a virgin copy.... I'll report back tonight..
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Yeah, looks like something is wrong in the changes you made to Settings.php.  Most likely an extra or missing quote.  Check for both " and ' (don't know how many times I've started a string with one and terminated with the other).

Could also be an unmatched brace / bracket: ( or [
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Davis Instruments Weather Stations / Re: VP2 anemometer cups sticking
« Last post by Ian. on Today at 12:57:02 PM »
Thanks SnowHiker,

I managed to get the bearing and brass follower out of the anemometer body, I wasn't sure if the bearing was flanged like some of the pictures others have posted and if it was, which way would it come out.

Looking at it again under a strong light, I couldn't see any lip and it turned out on my version it was simply an interferance fit, using a screwdriver and gently tapping allowed the bearing to dislodge into the body housing, to remove the brass follower I turned the body over and tapped this out.

I'll post up pictures of re-assembly when the new reed and bearing arrives.

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Davis Instruments Weather Stations / Re: More than 8 Stations?
« Last post by johnd on Today at 12:33:43 PM »
Is it possible thru whatever means to have more than 8 stations at a site?

No, not within wireless range of one another. Sometimes you can add more sensors than you might think at first, eg if you're just after temperature readings then you can add six temp sensors to a 6345 transmitter for instance. But other limitations might still kick in, eg only one 'full' 6345 or two partials, sometimes the console can display readings from multiple sensors but software cannot log them all...etc

For many sensors at one site you need to be looking at Davis Enviromonitor allowing 4 sensors per node and eg 20 nodes per gateway.
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Davis Instruments Weather Stations / Re: VP2 anemometer cups sticking
« Last post by SnowHiker on Today at 12:22:09 PM »
I have replaced my 2013 anemometer today as the reed switch has failed.

I'll try and refurbish the old one by changing the reed and bearings, how do you get into the unit, does the body split?, how is it fixed together?

Update - Google was my friend http://www.cjoint.com/15ma/ECAj5A762FD_changement_ils.pdf

Update 2 - Removed the wind direction pot and reed switch assembly, how does the bearings come out??, any tips please.
Maybe try this topic: http://www.wxforum.net/index.php?topic=28664.0

It may depend on how old your anemometer is, the older ones didn't seem to have an easy, nondestructive way to remove the bearings, as far as I could see.  Apparently they changed that in the VP2/brass tip era.
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Davis Instruments Weather Stations / More than 8 Stations?
« Last post by azchrisf on Today at 12:20:04 PM »
Is it possible thru whatever means to have more than 8 stations at a site?
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