[R] Extracting wind direction and wind speed from wind rose plot

[Ebert,Timothy Aaron]

1) If you already have two data frames, one as shown, the other with Wind_Speed and Wind_Dir, then you can use cbind() to join them if they have the same number of rows. If not, then you will have to edit one of the data frames (to get the same number of rows) or add column(s) so that both data frames have a column in common and then use something like full_join() from the dplyr package.

2) If you have roughly 44,000 wind rose plots (one for each hour, 5-years), and need to extract speed and direction, then you will need some automated image analysis program. It would be easier if you can get access to the data used to generate the wind rose plots, but I assume you have already tried that. This is more challenging if you have digital scans of printed plots where paper color, and ink changes over time. There may be other complications if (for example) the pictures are not all oriented in the same direction.
2a) If plots have speed and direction written on them then OCR might help.
2b) If plots have arrows you could focus on identifying arrow direction and length using image analysis.
2c) If plots show more of a distribution, then you may need an image analysis approach to efficiently get through all the images: train a convolutional neural network. Simplifying wind as speed and direction may need clarification. There is average [arithmetic, geometric, ...], minimum, or maximum speed and most frequent direction (mode, median, average direction?). The general concept is abundantly clear, but the details are problems.

To me, option 2c is more a Python sort of problem, but it can be done in R.

Tim

-----Original Message-----
From: R-help <r-help-bounces using r-project.org> On Behalf Of Jeff Newmiller via R-help
Sent: Wednesday, October 30, 2024 9:27 AM
To: r-help using r-project.org
Subject: Re: [R] Extracting wind direction and wind speed from wind rose plot

[External Email]

A wind rose plot omits time information. Your request is simply not possible.


On October 30, 2024 3:48:03 AM PDT, javad bayat <j.bayat194 using gmail.com> wrote:
>Dear all;
>I am searching for a way to extract wind direction and speed from a
>wind rose plot. I have a graph and I want to make a dataframe of 5
>years with hourly intervals.
>
>> start_date <- as.POSIXct("2019-01-01 00:00:00") end_date <-
>> as.POSIXct("2023-12-31 23:00:00") time_sequence <- seq(from =
>> start_date, to = end_date, by = "hour")
>
>> df <- data.frame(
>  year = as.integer(format(time_sequence, "%Y")),
>  month = as.integer(format(time_sequence, "%m")),
>  day = as.integer(format(time_sequence, "%d")),
>  hour = as.integer(format(time_sequence, "%H"))
>)
>
>> head(df)
>  year month day hour
>1 2019     1   1    0
>2 2019     1   1    1
>3 2019     1   1    2
>4 2019     1   1    3
>5 2019     1   1    4
>6 2019     1   1    5
>
>
>And I want to add 2 more cols to this dataframe as Wind_Dir and
>Wind_Speed that the data extracted from the plot by analyzing it.
>Is there any library to do this? or any function to write for this purpose?
>I would be more than happy if you please help me to do this.
>Sincerely
>
>
>
>
>
>
>

--
Sent from my phone. Please excuse my brevity.

______________________________________________
R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide https://www.r-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.