tri/biangulation app

[vortmax]

I'm looking for an app that can do baisc triangulation or biangulation. The basic idea is to use the camera center on a distant object, then record the current GPS location and compass bearing to object. You then move some place else and do it again. The apparently would then calculate where the two projected bearings cross and display the point on a map.

I've seen apps that calculate distance like this or use this method to find your location, but none that will geolocate objects in the distance.

 

[lennyjew]

Without knowing the size of the object and scale that it appears as in the picture there is no real way for it to calculate something.

In order for triangulation or biangulation to work you have to know the distance between the reference point and the object.

Maybe it's just me, but I'm just not seeing how it would work without filling in a lot of blanks.

 

[vortmax]

Its the same way cell tower triangulation works, but backwards.

Say you have a map and compass. You stand at a known location and see a mountain in the distance. You take a compass bearing to the mountain and draw a line on the map starting at your current position, following the compass bearing. Now, you know that mountain is somewhere along that line. So if you move to a different location and do it again, you will have 2 lines, and where they cross is where the mountain is.

All you need to know is a GPS location and compass bearing to the object from at least 2 locations.

 

[RazzMaTazz]

I don't think that there's any reasonable way to make it work with the camera because (at least in my LG Optimus S) the magnetometer (and therefore compass reading) only points north when the phone is in a relatively horizontal orientation (like when you lay it on a table). But the phone can only take a photo of a point on the horizon when the phone is in a vertical orientation-- during which the magnetometer (compass reading) goes crazy.

Even if you could get around that, the app would also have to make the assumption that the camera was perfectly perpendicular to the magnetometer (or it would require some calibration). If they were off-perpendicular by even 1 degree, it would have a pretty bad impact on the results, depending on the distance of the target. I'm also not sure that the magnetometers are accurate enough to do a great job.