The new improved Skybuild Land Border Detector will do spot checks like the original PLUS it can map out your land for you by dropping a marker at each corner that your lot makes, so it will map any contour. The markers default to a flash, but can also be made to create a particle 'string' to outline your land. If you're going to leave them up for a long time, you can also turn off the listen on the markers to help prevent lag!!!
the SLBD itself is 1 prim, each marker is an additional 2 prims.
An excellent tool for helping someone (like me!) with a bizarre plot shape build effectively. The creator was extremely responsive and helpful, making changes in the scripting which included increasing the number of markers deployed and changing the placement so that it was exclusively on land ownership and not build-on-land permission. Thoroughly recommended.
This really makes my sky builds loads easier, and it's convenient that I don't have to TP down to the ground to check my prim usage anymore too!