Giving time series data

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sankee82
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Giving time series data

Post by sankee82 » Tue Oct 02, 2018 9:28 pm

I have given time series data as input to my variables. The data is annual in nature. I have set the time step to year in initial settings of the model. However when I am trying to plot the variable it is observed that the values are plotted with an interval of one month. How to rectify it?

tomfid
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Re: Giving time series data

Post by tomfid » Tue Oct 02, 2018 9:36 pm

You probably just need to change the unit for Time in Model>Settings>Time Bounds.

After you've done that, you should define and check all your other units.

sankee82
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Vensim version: DSS

Re: Giving time series data

Post by sankee82 » Tue Oct 02, 2018 9:40 pm

tomfid wrote:
Tue Oct 02, 2018 9:36 pm
You probably just need to change the unit for Time in Model>Settings>Time Bounds.

After you've done that, you should define and check all your other units.
I have already done it. Still the data is taken at a step of one month.

tomfid
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Re: Giving time series data

Post by tomfid » Tue Oct 02, 2018 10:01 pm

Can you post the model & data, or a screenshot of a sample of each?

sankee82
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Re: Giving time series data

Post by sankee82 » Wed Oct 03, 2018 12:45 pm

tomfid wrote:
Tue Oct 02, 2018 10:01 pm
Can you post the model & data, or a screenshot of a sample of each?
I am attaching model, excel data and graph of one of the variable.
Attachments
potential_gwr.xlsx
(12.28 KiB) Downloaded 40 times
well water data.png
well water data.png (6.33 KiB) Viewed 1093 times
Vensim.pdf
(36.52 KiB) Downloaded 47 times

tomfid
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Re: Giving time series data

Post by tomfid » Wed Oct 03, 2018 4:35 pm

The Year column in your spreadsheet is not numeric, it's text. I'm not sure what Vensim is assuming about the time axis, because you haven't provided the equations or imported .vdf, but I'm guessing that if you fix the timing it will work.

sankee82
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Vensim version: DSS

Re: Giving time series data

Post by sankee82 » Sun Oct 07, 2018 12:22 pm

I am unable to understand how to use the imported data in writing equations involving time series. Can you please help me with it. I know this is very small thing to ask for, but as I am new to Vensim it is talking me a lot of time to figure out.

tomfid
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Re: Giving time series data

Post by tomfid » Sun Oct 07, 2018 7:18 pm

This might be a good place to start: http://vensim.com/documentation/usr16.htm

JudeChen
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Re: Giving time series data

Post by JudeChen » Wed Oct 09, 2019 4:05 pm

Hi,

If my Units for Time is set at Yearly, and my Time Step is at 0.0625, does Vensim read XLS data for time in the monthly or yearly manner here?

I am currently using the VensimDSS (S/N 9510), academic use license although it says VensimPLE on my profile.

tomfid
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Re: Giving time series data

Post by tomfid » Wed Oct 09, 2019 5:22 pm

Vensim will be looking for time formatted as a decimal year.

JudeChen
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Re: Giving time series data

Post by JudeChen » Thu Oct 10, 2019 1:29 am

tomfid wrote:
Wed Oct 09, 2019 5:22 pm
Vensim will be looking for time formatted as a decimal year.
Okay. thanks! So should i input the info as based on monthly or yearly data?

Administrator
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Re: Giving time series data

Post by Administrator » Thu Oct 10, 2019 6:54 am

If your model runs in years, then input it as yearly data if you can as otherwise things can get confusing.
Advice to posters seeking help (it really helps us to help you)
http://www.ventanasystems.co.uk/forum/v ... f=2&t=4391

Units are important!
http://www.bbc.co.uk/news/magazine-27509559

tomfid
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Re: Giving time series data

Post by tomfid » Thu Oct 10, 2019 1:46 pm

Are you talking about the units or granularity of the data? Generally it's always better to use the finest time scale you can, given the time step of the model.

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