Does anyone know what the white cross markings in the corner of some farm fields are for. I assume that they might be for aerial boundary mapping?????

I assumed the same thing but don’t know for sure, I’ve seen 2 or 3 around.

Yes, they’re alignment marks so each aerial image has distinctive corners.  If you look carefully, some are corner ‘L’ shapes and sum are ‘+’ shapes.

There are some on the road on 851 in Fawn Grove where it makes the hard left before you head into MD.  I always wondered what those were for!

That’s my something new for today...I can rest easy now.

Those are control points for aerial mapping.  There is a spike or a nail in the center of the cross or at the corner of the L which have precise coordinates on them.  Most likely located with a GPS unit.  They are used to orient a series of photographs.  The photos need to be precisley oriented in order to correctly view them in 3D and produce an accurate topograpical map.

Thanks for taking the time to educate me on this. Just one of those things you see and always wounder about.
This site is a great tool but like all tools it must be used properly to work!

On a related note: I’ve always wondered what the signs next to the fields indicate.  They have some sort of code on them.  Is it the seed strain or something?

I recall a farmer telling me once they are for different types of seeds they are playing around with. Usually some sort of discount for the seeds in trade for using your soil to test them out. Certain requirements have to be met though such as types of fertilizer used.

Thanks very much.

Alex - 30 April 2008 11:58 AM

I recall a farmer telling me once they are for different types of seeds they are playing around with. Usually some sort of discount for the seeds in trade for using your soil to test them out. Certain requirements have to be met though such as types of fertilizer used.

Some of the numbers on the signs stand for companies they sell the crop to and or seed type they use. every few years they change between corn and low vegitation because its good for the ground. If they dont have numbers some farmers use those crops are for feed for their animals. but they signs are pretty much just marking areas for their own use to tell them how much crop goes to what ever purpose. And of couse there is a number on the sign showing what kind of chemicals “may be” used for that area. More less for our own good and health.