# Coordinates Mis-matched when graphing points from spreadsheet

I have a problem with points graphing incorrectly from the spreadsheet. It is not keeping the correct points together because there are empty cells.

Notice the way the data is entered in column C. I want column A to be the x-coordinate and then column C to be the y-coordinate, but there are a bunch of empty cells in column C because of how the data is recorded. No matter what I do, when I go to create and graph a list points, the program is taking the first available value in column A as the x-coord and then the first non-empty cell in column C as the y-coord.

So for example, instead of graphing the point as (A22, C22), the point being created is (A6, C22). How can I prevent this mismatch?

How can I set up a list of points where it ignores incomplete sets of point (ex. {A6, C6} through {A21, C21}) and starts graphing at {A22, C22}?

Work with a matrix created as a copy from the spreadsheet.

m1 = KeepIf(Length(RemoveUndefined(L)) > 0, L, Sequence(Sequence(Cell(X, Y), X, 1, 6), Y, 6, 115))

All dependend objects and lists then refer exclusively to SpreadsheetCopy (directly or indirectly)

.

example: you need all defined (not == ?) Europa-Data:

LstEuropa = KeepIf(IsDefined(Element(L, 1)) ∧ IsDefined(Element(L, 3)), L, m1)

I'm sorry, I just can't quite follow that and I've been working on it for two hours.

What is L? I don't have a variable L currently defined. Is that the list of ordered pairs (EuropaPoints, for example) or is it the list of data points in the column I'm working in (Ex. ListEuropa - defined as C6:C115)?

Since my data first begins in row 6 and could theoretically run to row 115, would that means that I'd go:

Sequence (Sequence(Cell(X,Y),X,6,115),Y6,115))

I'm testing this is much as I can but Geogebra keeps crashing/freezing...

Why not just copy the numbers to new columns? If you can't do that then how about:

select rows of column A, then press ctrl and select the rows in column C

then right click-->create-->list of points

or

Zip((a, b), b, C22:C38, a, A22:A38)

Please explain the complete workflow that your "hundreds of students" are doing

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