Topographic maps from decades ago are killing my survey accuracy

Tried to use a map from the 70s for a current project, and the river channels have moved miles. The contour lines don't match the ground at all. Had to redo entire sections by hand with GPS, which wasted a full day. Why can't we get better resources for basic geology work?

3 comments

3 Comments

the_brian1mo ago

Old maps are a classic trap. I've started checking current aerial photos online to save the headache.

margaret_kelly551mo ago

But @the_brian, how OFTEN do aerial photos still lead you astray compared to old maps?

terryf421mo ago

Wait, the river moved miles since the 70s... that's wild. Landscapes change way more than people realize. No wonder your survey got messed up.