Julian Date

[ElPelado]

how i convert julian date to "normal dat" and the oposite?

[Commander David]

Hi ElPelado,

i`ve asked this question for a long time and i got this Link as answer:
http://aa.usno.navy.mil/data/docs/JulianDate.html

hope it helps you.

[jrobert]

Here's a way to do it. It's written in the form of a Visual Basic function so it should be pretty easy to follow.

Code: Select all

Function JulianToDate(ByVal plJulian As Long) As Date
    Dim sJulian As String
    Dim bCentury As Byte
    Dim iYear As Integer
    Dim iDay As Integer
    ' Pad with leading zeros
    sJulian = String(6 - Len(CStr(plJulian)), "0") + CStr(plJulian)
    ' Breakdown...
    bCentury = CByte(Left(sJulian, 1))
    iYear = (1900 + (bCentury * 100) + CByte(Mid(sJulian, 2, 2)))
    iDay = CInt(Mid(sJulian, 4, 3))
    ' Return the gregorian date
    JulianToDate = DateAdd("d", iDay - 1, DateSerial(iYear, 1, 1))
End Function

[ElPelado]

thank you both!
jrobert: can you explain me where to put that code? i used the visual basic, but i forgot...

[jrobert]

Rather than trying to explain it (which is something I'm not very good at when it comes to code ), I'll paste the contents of the form1.frm file here... All you need to do is copy/paste it into a blank text file and rename it to form1.frm.

Code: Select all

VERSION 5.00
Begin VB.Form Form1
   Caption         =   "Form1"
   ClientHeight    =   1545
   ClientLeft      =   1620
   ClientTop       =   1755
   ClientWidth     =   2610
   LinkTopic       =   "Form1"
   ScaleHeight     =   1545
   ScaleWidth      =   2610
   Begin VB.CommandButton Command1
      Caption         =   "Get Date"
      Default         =   -1  'True
      Height          =   375
      Left            =   120
      TabIndex        =   2
      Top             =   1080
      Width           =   2295
   End
   Begin VB.TextBox Text1
      Height          =   375
      Left            =   120
      TabIndex        =   1
      Text            =   "<Enter Julian Number Here>"
      Top             =   600
      Width           =   2235
   End
   Begin VB.Label Label1
      Height          =   375
      Left            =   120
      TabIndex        =   0
      Top             =   120
      Width           =   2295
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Function JulianToDate(ByVal plJulian As Long) As Date
    Dim sJulian As String
    Dim bCentury As Byte
    Dim iYear As Integer
    Dim iDay As Integer
    ' Pad with leading zeros
    sJulian = String(6 - Len(CStr(plJulian)), "0") + CStr(plJulian)
    ' Breakdown...
    bCentury = CByte(Left(sJulian, 1))
    iYear = (1900 + (bCentury * 100) + CByte(Mid(sJulian, 2, 2)))
    iDay = CInt(Mid(sJulian, 4, 3))
    ' Return the gregorian date
    JulianToDate = DateAdd("d", iDay - 1, DateSerial(iYear, 1, 1))
End Function

Private Sub Command1_Click()
    If IsNumeric(Text1) And Len(Text1) <= 6 Then
        Label1 = JulianToDate(Text1)
    End If
    Text1.SetFocus
    Text1_GotFocus
End Sub

Private Sub Text1_GotFocus()
    Text1.SelStart = 0
    Text1.SelLength = Len(Text1)
End Sub

Private Sub Text1_Validate(cancel As Boolean)
    If Not (IsNumeric(Text1) And Len(Text1) <= 6) Then
        cancel = True
        Text1.SetFocus
    End If
End Sub