I’ve been laying out our property in NY w/ a view towards subdividing and have had some success using a drawing program (Procreate) to layer multiple images including aerials (mostly Google Earth), screenshots of LiDAR and wetlands (
The National Map) and County maps of properties that the GIS online maps are based on. I take the wetland in their hydrography layers with a grain of salt as the stream paths seem to be offset 50 feet from the course plainly visible in the LiDar. The older topo maps (available as an alternate base map layer in the Map) were more accurate as far as stream paths. Likely some sort of base map shift like Paul Harvey cautioned about. The hydrography also contains accurate catchment maps based on the LiDar, allowing the ability to measure areas to estimate how much water it receives.
The ability to adjust transparency of the layers in Procreate in order to overlay the lot lines from the
County property maps, matching up roads and terrain as accurately as possible. The northern and southern borders align with the Kayderosseros Patent survey, which was completed and filed in 1770. Centuries of timber harvests and clearings have built up berms along those lines in places where slash and roots have been discarded along with old border trees not being cleared, old roads and fence lines corresponding to the 1770 survey providing evidence of occupation that is visible on the LiDar images. Our S-W back corner is memorialized by a galvanized post set in the 1960’s survey sits on the edge of a ravine has helped tighten the accuracy of my estimates by comparing it to the LiDar.
One oddity we ran into was our north-south rear property line, that I had presumed was at a right angle to the northern and southern lines that correspond to the 1770 Patent survey lines, turned out to not be a right angle after all. In laying out division lines in Procreate I used the rear line as a reference. I also created lines using the N-W property lines as reference and rotating them 90 degrees in the app, resulting in a subtle difference in some lines that made everything look caddywhompus until I discovered the difference. I researched
old maps and found that when the original 1855 survey was conducted the N-S rear line likely ran at a perfect right angle to the E-W line, but improvements when the road was first paved in the 1920’s cut about 50 feet off the SW corner of the property to smooth a sudden 35 degree turn in the State road, moving the S-E corner 50 foot east. So the 1960’s survey was accurate insofar as measuring rods and chains from today’s road. Changing the road path and so moving the rear corner over added a narrow slice of about an acre to our property, more or less. It’s mostly ravine and wetlands and no habitation nearby, so really of no import.
