Geo-location and Solar North

Dave R

Do you have the Solar North plugin from the Extension Warehouse? It would let you set the Solar North angle.

sfto1

Dave,

I do have the Solar North plugin installed. I'm confused why the green axis and Solar north do not line up, and more importantly I need to know what the SU shadows are generated from. If I reset Solar North to the green axis in the geo-located model, the image and models do not move, but the shadows do change. What is inherently "North" when geo-locating?

pbacot

Why should you need to set the Solar North angle if the model is geo-referenced? (I'm assuming there's reasonable accuracy in this SU feature)

Perhaps the north (green axis) in "Find Location" is the local grid north--which isn't the same as solar north--or am I mistaken? Would be nice if Trimble could provide more technical information on this. Maybe this should be handed over to your surveyors to figure out. If our present day surveyors can't match Stonehenge we're in trouble.

Dave R

Hmmm... I wrote a reply and it disappeared.

Solar North and True North don't necessarily coincide. Maps are set up for True North, not Solar North.

Solar North occurs when the sun is at its zenith. We generally think of that as occurring at noon but the actual time it occurs depends upon where in the time zone your model is geo-located.

sfto1

So, I should reasonably expect real world shadow behavior similar to the shadows generated in a geo-located model if I convey construction staking coordinates based off of True North???

Dave R

Yes. I would think you should.

sfto1

Thanks Dave!

Dave R

You're quite welcome. I hope the monument gets installed correctly. You could mount it on a large lazy Susan so it can be rotated to face the sun as needed. Sort of a real life Face Me component.

pbacot

Thanks Dave. Good to know.

sfto1

@dave r said:

You're quite welcome. I hope the monument gets installed correctly. You could mount it on a large lazy Susan so it can be rotated to face the sun as needed. Sort of a real life Face Me component.

It might come to that

One more question. The Longitude and latitude appears to be in decimal format. Is that everyone else's understanding? As in 45.37770 degrees not 45 degrees 37 minutes and 77 seconds.
Surveyor asked for a clarification.

Dave R

Yep. Decimal format for Lat/Long.

sfto1

Then I believe I'm set.

Dave R

Perfect.