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Thread Subject:
Function to fill gaps in data needed

Subject: Function to fill gaps in data needed

From: Jose Miguel

Date: 14 Jul, 2011 07:04:13

Message: 1 of 2

Dear all,

I work with wind data, files containing a row of data every 10 minutes and 8 to 12 columns (usually columns are, year-month-day-hour-minute-wind speed-wind speed deviation-wind direction).

In everything went perfectly we should have 144 data each day, but 100% of the cases have some missing data (due to electronic failures, icing, tower collapse, human mistakes…).

In some cases, we need to fill these gaps, for many purposes, energy calculations, availability calculations ...

We need a Matlab routine that is able to fill this gaps according to the following criteria:
• Ideally it’d be desirable that the routine works with all time stamps, not only 10 minute data (if this is not possible, we’d choose 10 minutes as the time stamp)
• We should have the control over the values of the variables to fill in (wind speed-wind speed deviation-wind direction); obviously the year-month-day-hour-minute data should be generated by the algorithm, as they are given time and date data).
This is because for example sometimes we’d like to fill in the gaps in wind speed with 0 or maybe with the mean wind speed of all data or even with NaN values.
If you need some default values, maybe you could choose 999 for any variable with no information regarding the value to fill in.
• The program should be ready to work with at least 12 columns (this example of data is 8 columns but sometimes data is up to 12 columns)

This is an offer to anybody to make us a routine for these purposes, we’ll pay your honoraries and assistance.

Please let me know your thoughts / questions,
Thank you very much for your attention,
Jose Miguel Jauregui

Subject: Function to fill gaps in data needed

From: ImageAnalyst

Date: 14 Jul, 2011 13:42:20

Message: 2 of 2

Jose Miguel :
Are you looking to fill in missing columns? Or missing rows?

If you're looking to fill in missing columns, I think you have to know
in advance somehow which columns are missing. Let's say you have a
row and in it there are 9 numbers. How do you know if you're missing
measurements (i.e. columns) 3, 6, and 11, or missing 2, 5, and 12?

If you're looking to fill in missing rows, for example you have data
for 9:50, 10:00, 10:20, and 10:30 but the row for 10:10 is missing,
then what do you plan to do if the two rows on either side of the
missing row have different numbers of columns? Like 10:00 has 9
columns but 10:20 has 12 columns? How many columns should 10:10 have
and how should they be constructed?

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