How to sort the (min and max) X and Y axis of the chart in VB .NET 2010

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I read a text file and plot the points on a chart. The file has randomly arranged numbers in columns. Initially, the program is getting the minimum and maximum numbers from the columns as per my requirement. After that, I plot them on to a chart, but the X and Y axis are not sorted. The axis are showing the random numbers rather than sorted values (min to max).
So far what I tried is copied below.
Please guide me how to change the color and size of the points in the chart to differentiate as I will have to load multiple files later.

THANKS in advance !!!

What I have tried:

VB

Dim Textfile As String
        Dim openDlg As New OpenFileDialog

        If openDlg.ShowDialog() = DialogResult.OK Then
            openDlg.Filter = "txt files (*.txt)| *.txt|All files (*.*)|*.*"
            openDlg.FilterIndex = 2
            openDlg.RestoreDirectory = True
            Textfile = openDlg.FileName

            Dim filelines() As String = File.ReadAllLines(Textfile)

            Dim col1 As List(Of Long) = New List(Of Long)()
            Dim col2 As List(Of Long) = New List(Of Long)()
            Dim col3 As List(Of Double) = New List(Of Double)()
            Dim col4 As List(Of Double) = New List(Of Double)()

            Chart1.Series.Clear()
            Dim r As New Series
            r.Name = "Receivers"
            r.ChartType = SeriesChartType.Point
            Chart1.Series.Add(r)

            For Each fileline As String In filelines
                If fileline.StartsWith("R") Then fileline = fileline.Substring(1)
                Dim items() As String = fileline.Split(New Char() {CChar(vbTab), " "}, StringSplitOptions.RemoveEmptyEntries)

                Dim Linenum As Long
                Dim statnum As Double
                Dim Easting As Double
                Dim Northing As Double

                If Integer.TryParse(items(0), Linenum) Then col1.Add(Linenum)
                If Integer.TryParse(items(1), statnum) Then col2.Add(statnum)
                If Double.TryParse(items(2), Easting) Then col3.Add(Easting)
                If Double.TryParse(items(3), Northing) Then col4.Add(Northing)

                r.Points.AddXY(items(2), items(3))
                
               
            Next

            'sorting the columns to get min and max
            col1.Sort()
            col2.Sort()
            col3.Sort()
            col4.Sort()
            
            'getting maximum and minimum value of 4 columns
            Me.Linemax.Text = col1.Item(col1.Count - 1).ToString()
            Me.Linemin.Text = col1.Item(0).ToString()
            Me.statemax.Text = col2.Item(col2.Count - 1).ToString()
            Me.statmin.Text = col2.Item(0).ToString()
            Me.Eastmax.Text = col3.Item(col3.Count - 1).ToString()
            Me.Eastmin.Text = col3.Item(0).ToString()
            Me.Northmax.Text = col4.Item(col4.Count - 1).ToString()
            Me.Northmin.Text = col4.Item(0).ToString()


            'restricted Y axis as per the maximum and minimum values in the column
            Chart1.ChartAreas(0).AxisY.Minimum = col4.Item(0).ToString()
            Chart1.ChartAreas(0).AxisY.Maximum = col4.Item(col4.Count - 1).ToString()
            

        End If
    End Sub

Posted 7-Jan-18 18:41pm

VB_Learner

Updated 8-Jan-18 9:22am

Karthik_Mahalingam

v2

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Comments

Ralf Meier 8-Jan-18 3:32am

Post some of the real values from one of your files ... In the Moment I have no idea where your problem is ...

VB_Learner 8-Jan-18 5:03am

Hi Ralf,

The data example is somewhat like this ..

194787.5 2667200.0
194812.5 2667200.0
195662.5 2667200.0
195687.5 2667200.0
201937.5 2667350.0
195737.5 2667200.0
195762.5 2667200.0
195787.5 2667200.0
196512.5 2667200.0
201837.5 2667350.0
198562.5 2667650.0
201887.5 2667350.0
201912.5 2667350.0
198187.5 2667500.0
201962.5 2667350.0
201987.5 2667350.0
202012.5 2667350.0
198412.5 2667650.0

Ralf Meier 8-Jan-18 7:11am

Thanks ... now I have other questions ...
Your example show a List with X- and Y-Values - this will be two 1D-Array's or one 2D-Array.
So you would have all X-Values in col1 and all Y-Values in col2 ...?
In your code-snippet you have 4 Collections - what does that mean ? Different Curves ?
I guess that Xmin will be col1(0) and Xmax will be col1(col1.Count - 1) - the same to Y : Ymin will be col2(0) and Ymax will be col2(col2.Count - 1) ... but you assign col4 - what does that mean ? Please explain ...

VB_Learner 8-Jan-18 7:14am

Yes there are 4 columns.. .I only sent the example of 2 columns which I am plotting.. the first 2 columns are just integers which I don't want to plot yet. I only want these two columns to plot as points ... I am only facing problem in sorting the axis X - Y of chart to start from Min to Max .. i hope you got my point..

Ralf Meier 8-Jan-18 9:44am

OK ... but that is what you allready do - so which part doesn't work until now ?

VB_Learner 8-Jan-18 12:26pm

I believe you have ploted the data on the chart.. can you see that the X axis are in ascending order?? .. my question is related to the sort of the X and Y axis that they are not sorted from min to max ... please plot the data and have a look ... is there any way I can attach a jpg image to clarify my problem??

Ralf Meier 8-Jan-18 15:08pm

I think I understand now - see my Solution ...

VB_Learner 8-Jan-18 23:07pm

Thanks for the efforts.. but unfortunately this solution will only work if I have limited lines (10-20) only. My original file has 5000 lines and this solution will not work for sure. I have copied all the 4 columns below. Please run my original code which I posted in the question and have a look at the X axis. You will find that the chart's X axis is not sorted for graph representation. e.g. if the graph starts from 0 - 10, the interval in my graph is showing 0-1-2-5-6-4-7-9-8-3 etc.
R2072 2193 194787.5 2667200.0
R2072 2194 194812.5 2667200.0
R2072 2195 195662.5 2667200.0
R2072 2196 195687.5 2667200.0
R2072 2197 201937.5 2667350.0
R2072 2198 195737.5 2667200.0
R2072 2199 195762.5 2667200.0
R2072 2200 195787.5 2667200.0
R2072 2201 196512.5 2667200.0
R2072 2202 201837.5 2667350.0
R2072 2203 198562.5 2667650.0
R2072 2204 201887.5 2667350.0
R2072 2205 201912.5 2667350.0
R2072 2206 198187.5 2667500.0
R2072 2207 201962.5 2667350.0
R2072 2208 201987.5 2667350.0
R2072 2209 202012.5 2667350.0

Ralf Meier 9-Jan-18 4:42am

In the Moment I don't understand.
In my code-snippet I worked with direct assigning the Values to the Lists because I don't have your file.
Basicly (for the posted code) there is not difference if you have 18 value-Lines or 5000 - you only need more time for sorting and assigning to the Chart.
Your basic Problem in your code (as I wrote in my Solution) is that you allways assign Strings to those Chart-Properties which are awaiting numeric Values - that's the difference between your code and mine - I assign Double-Values ... either to the Chart-Scaling but also to the Chart-Points.

But ... what do you mean with "the interval in my graph is showing 0-1-2-5-6-4-7-9-8-3 etc. " ...? I don't understand this.

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Ralf Meier · Answer 1 · 2018-01-08T09:07:00

OK ... I have made some test with your data and your code.
At least some changes where necessary. I think with my method-sample it would be easy for you to modify your code that it works.

VB

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click

        Dim col3 As New List(Of Double)
        Dim col4 As New List(Of Double)
        Dim Easting As Double
        Dim Northing As Double

        Dim s(17) As String
        Dim item As String()
        s(0) = "194787.5 2667200.0"
        s(1) = "194812.5 2667200.0"
        s(2) = "195662.5 2667200.0"
        s(3) = "195687.5 2667200.0"
        s(4) = "201937.5 2667350.0"
        s(5) = "195737.5 2667200.0"
        s(6) = "195762.5 2667200.0"
        s(7) = "195787.5 2667200.0"
        s(8) = "196512.5 2667200.0"
        s(9) = "201837.5 2667350.0"
        s(10) = "198562.5 2667650.0"
        s(11) = "201887.5 2667350.0"
        s(12) = "201912.5 2667350.0"
        s(13) = "198187.5 2667500.0"
        s(14) = "201962.5 2667350.0"
        s(15) = "201987.5 2667350.0"
        s(16) = "202012.5 2667350.0"
        s(17) = "198412.5 2667650.0"

        For i As Integer = 0 To 17
            item = Split(s(i), " ")

            Easting = CDbl(item(0))
            Northing = CDbl(item(1))

            col3.Add(Easting)
            col4.Add(Northing)

            Chart1.Series(0).Points.AddXY(Easting, Northing)
        Next

        col3.Sort()
        col4.Sort()

        Chart1.ChartAreas(0).AxisX.Minimum = col3.Item(0)
        Chart1.ChartAreas(0).AxisX.Maximum = col3.Item(col3.Count - 1)
        Chart1.ChartAreas(0).AxisY.Minimum = col4.Item(0)
        Chart1.ChartAreas(0).AxisY.Maximum = col4.Item(col4.Count - 1)

    End Sub

In my opinion your basic mistake was that you all the time added strings as Chart-Limits and also as Chart-Points.