[siva.guduru]

Hello,

I am developing a Blackberry GPS application, my main motto is is to draw an arrow from souce to target showing direction. But the problem i am facing is i am getting the angle between source and destination by getAzimuth method of location api... if i draw the arrow using that angle... i am not able to rotate the arrow as per geographic direction of my phone.

Later i found out that i have to add up Orientation angle as well and as said in API If orientation angle is 0 then we are facing north, if 90 east, 180 south and 270 west 360 again north...

but when i am trying to get Orientation angle even i keep my phone steady towards north ia m getting different values each time i call to get the orientation. onr time i am getting 120 other time i am gettin 270 even though i am facing north. My hpone is 8820 smart hpone wit inbuilt GPS receiver.

Please help me regarding this.

Siva Charan Guduru.

[siva.guduru]

Hello,

Please help me regarding this... i want to know how to get stable orientaion value for device when we hold it in particular direction.

[ghane]

I am not a developer, so am not aware of the API you are using.

However, there is no way for the BB to know which way you are facing, north or south. By taking two position fixes close together, and drawing a line between them, we can estimate which way you are moving. However, this does not still tell us which way you were facing while walking, or the orientation of the phone.

You need a compass to detect orientation.

[siva.guduru]

But the J2ME location API provides an Orientation class... if implementation does not support the Orientation then it will throw the location exception.. but here in my case i am able to get the Orientation value, the real problem is what ever value i am getting is not constant even if i keep my device steadily in one position.

rgs,
Siva Charan Guduru.

[takeshi]

Re-read ghane's post. The orientation is probably based on two position fixes. Even so it's possible to obtain an incorrect orientation which is something you'll need to address in your code.

You can see this sort of behavior occasionally even in the best GPS apps. Again, the BB can't tell which way you're facing as it does not have a compass. You can make an educated guess based on prior positioning data though.

[CanuckBB]

The orientation is derived by the last 2 locations and an assumption that you are facing in the direction you are moving.

[RemyJ]

The API isn't BlackBerry specific so if a device happens to have a built in compass, you can get orientation while stopped.

[siva.guduru]

hello,

Thank you for all your replies...

Now if i want to convert two locations as two cordinates on screen how can i do that... supposee there is a location which i want o convert in to X and Y coordinates of screen to represetn on screen (x,y), is there any way i can do that.

I have a vague idea suppose if we have a Latitude if we can take some Cos and Sin values thani think we weill get some coordinate value but what about longitude then how can we go about longitude... where should we incorporate longitude in calculating the coordinate information.

Any Help regarding this would be of great use for me...

Thanks & Regards,
Siva Charan Guduru.

[ghane]

Originally Posted by siva.guduru

hello,

Thank you for all your replies...

Now if i want to convert two locations as two cordinates on screen how can i do that... supposee there is a location which i want o convert in to X and Y coordinates of screen to represetn on screen (x,y), is there any way i can do that.

I have a vague idea suppose if we have a Latitude if we can take some Cos and Sin values thani think we weill get some coordinate value but what about longitude then how can we go about longitude... where should we incorporate longitude in calculating the coordinate information.

Any Help regarding this would be of great use for me...

Thanks & Regards,
Siva Charan Guduru.

Simple, your Latitude is the Y coordinate, and the Longitude is the X coordinate. That is absolutely correct, if you assume the earth is flat. The assumption is reasonable unless:

1. You are near the poles
2. The two points are far from each other, eg a few thousand km

Once you have the two points, scale correctly.