RE: Obtaining direction from course heading

wm.chatman

Well-Known Member
Licensed User
Hello Folks

Would you could you be kind enough, to help this Mann that does not know enough???

I have been trying to implement this function. (Obtaining direction from course heading).

This function returns a string direction such as "north," "east southeast," etc from a heading between 0 and 360 degrees.

Sub getDirection(COG)
Dim direction
if COG >= 0 And COG <= 11.25 Then direction = "north"
if COG > 348.75 and COG <= 360 Then direction = "north"
if COG > 11.25 and COG <= 33.75 Then direction = "north northeast"
if COG > 33.75 And COG <= 56.25 Then direction = "northeast"
if COG > 56.25 And COG <= 78.75 Then direction = "east northeast"
if COG > 78.75 And COG <= 101.25 Then direction = "east"
if COG > 101.25 And COG <= 123.75 Then direction = "east southeast"
if COG > 123.75 And COG <= 146.25 Then direction = "southeast"
if COG > 146.25 And COG <= 168.75 Then direction = "south southeast"
if COG > 168.75 And COG <= 191.25 Then direction = "south"
if COG > 191.25 And COG <= 213.75 Then direction = "south southwest"
if COG > 213.75 And COG <= 236.25 Then direction = "southwest"
if COG > 236.25 And COG <= 258.75 Then direction = "west southwest"
if COG > 258.75 And COG <= 281.25 Then direction = "west"
if COG > 281.25 And COG <= 303.75 Then direction = "west northwest"
if COG > 303.75 And COG <= 326.25 Then direction = "northwest"
if COG > 326.25 And COG <= 348.75 Then direction = "north northwest"
return direction
End Sub

:BangHead:I know we can use this with the GPS library to determine direction. Yust cant figure it out. How can i bind Sub getDirection(COG) with lblDirection?


I want to use a Label(lblDirection)to show the Direction, on the Form.
The App is running but..
I added the source code into the main Module.
Question? What am I missing and or forgetting here, because i can not get this to fire up.

Thank you for the Effort to help!!!:)

WmC

PC: Laptop CoreDUo, Windows XP SP2 E
PPC:hp5550"ARM"/Windows CE 4.2
Bayern, Germany
 
Last edited:

Erel

Administrator
Staff member
Licensed User
I've implemented your function in a different way:
B4X:
Sub Globals
    Dim directions(0)
    directions() = Array("north","north northeast","northeast","east northeast", _ 
        "east", "east southeast", "southeast", "south southeast", "south", "south southwest", _ 
        "southwest", "west southwest", "west", "west northwest", "northwest", "north northwest")
End Sub

Sub App_Start
    lblDirection.Text = getDirection(numericDirection) 
End Sub

Sub getDirection (COG)
    Dim direction
    direction = directions(Int(((COG + 11.25) Mod 360)/22.5))
    Return direction
End Sub
This line: lblDirection.Text = getDirection(numericDirection)
Sets the label text to the value returned from the function.
 

wm.chatman

Well-Known Member
Licensed User
Hello Erel

Ein Herzliches Dankeschoen for your help!

I've implemented your function to the App. Got a error saying:
Objekt reference not set to an instance of an object.(see pic1)
also lblDirection on the Main Form did not respond. So...

In Sub Globals I then added (Dim numericDirection). The response was lblDirection gave out (north), with a freeze like Reation.
lblDirection did NOT RESPOND, we do not have a function.
(see pic2) on this.
Question: Can a Timer Tick help here? Are there yet a small item i am missing?

Thank you for the Effort to help Erel!!!

WmC

Greetings from Bayern Germany to all.

PC: Laptop CoreDUo, Windows XP SP2 E
PPC:hp5550"ARM"/Windows CE 4.2
Bayern, Germany
 
Last edited:

wm.chatman

Well-Known Member
Licensed User
Hello Erel

Again, Dankeschoen for your help!

I've worked on your function to the App on the Weekend, and i am still taping in the Dark.

Such a small thing but i just can not shake hands with this variable function, that holds the GPS direction. I know now, that it is not all that simple to work with GPS.
Must say i am just a might TEED OFF at myself. But...

I hope you do not mind Erel, i uploaded the App. Could you please take a'peak'for me?
It took myself 11 Years to get PAT on VB4-6 working Databanks. NMEA and GPS is new to me.
We are willing to learn, and this is a great Site to do so, and if i may say so:
A prior Statement from myself, was uncalled for. I would like to Apologize for that.

Thank you for the Effort to help Erel!!!

WmC

Greetings from Bayern Germany to all.

PC: Laptop CoreDUo, Windows XP SP2 E
PPC:hp5550"ARM"/Windows CE 4.2
Bayern, Germany
 
Last edited:

wm.chatman

Well-Known Member
Licensed User
Hello Erel

Again, Dankeschoen for your help but I don't understand the solution.

WmC

Greetings from Bayern Germany to all.

PC: Laptop CoreDUo, Windows XP SP2 E
PPC:hp5550"ARM"/Windows CE 4.2
Bayern, Germany
 

agraham

Expert
Licensed User
You have this "lblDirection.Text = getDirection(numericDirection)" in AppStart where it only gets executed once :( Also "numericDirection" never gets updated anyway :confused:

You need to put the label update in the "GPS_GPSDecoded" and use the updated course.

B4X:
If GPS.CourseOverGround <> "" Then
    Rotate(GPS.CourseOverGround) 'Rotate the compass arrow.
    lblCourse.Text = Round(GPS.CourseOverGround)
    [COLOR="Red"]lblDirection.Text = getDirection(lblCourse.Text ) [/COLOR] 
End If
 

wm.chatman

Well-Known Member
Licensed User
Dankeschoen an Erel und Agraham

Hi Erel and agraham

Thanks very much for your responses.
I came near to this solution, but was not quite right yet.:sign0161:

Again, Thank you for your time help and effort!!!

Sinceraly,
WmC

PC: Laptop CoreDUo, Windows XP SP2 E
PPC:hp5555"ARM"/Windows CE 4.2
Bayern/Germany
 
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