Topo Survey
Topo Survey
(OP)
Hi,
I have a surveyor who is doing a topographic survey of about 200 acres of land. The land is not flat and has several undulations. The surveyor has generated a topographic map with 1m contour survey using a grid of spot heights of at 10-15 meter spacings.
My question is whether this spacing can give an accurate enough survey for doing road design, masterplanning etc.
If not what is the general recommendation.
I have attached a file for reference.
Thanks
I have a surveyor who is doing a topographic survey of about 200 acres of land. The land is not flat and has several undulations. The surveyor has generated a topographic map with 1m contour survey using a grid of spot heights of at 10-15 meter spacings.
My question is whether this spacing can give an accurate enough survey for doing road design, masterplanning etc.
If not what is the general recommendation.
I have attached a file for reference.
Thanks





RE: Topo Survey
For general master planning and concept layout, I would ask to have at least 5 foot contour elevations on a 100 foot grid of spot shots. That would be less precision than the 1m elevation with 15m spot shots you mention.
For final design, I would want to have 1' contours with a grid spacing not more than 50' apart. The surveyor should also pick up top and toe of slopes for undulations or unique features, to build an accurate surface (for your cut and fill quantities eventually). Also, the surveyor should pick up all utilites such as culvert size, location, elevation. Water and sanitary sewer appurtenances (valves, manholes, invert elevations of pipe). Power poles, utility pads, etc. Perhaps trees as well, if you have to mitigate their removal.
Don't forget the importance of an accurate property boundary boundary description as well. You wouldn't want to master plan a development only to find out later part of it is on some one else's property...back to the drawin' board!
RE: Topo Survey
RE: Topo Survey
RE: Topo Survey
Most persons have responded that closer contours would be recommended.
If I use the spot heights given by the surveyor, I can generate a topo to any precision.
I appreciate the comment about getting the heights at the top and bottom of slopes but with land that has this many undulations, it would be easy for the surveyor to say his has taken this into consideration and even more difficult for me to verify. Hence my question regarding a general grid size.
Thanks.
RE: Topo Survey
RE: Topo Survey
RE: Topo Survey
RE: Topo Survey
RE: Topo Survey
Once you get out of the SD phase of work then you will have a good idea where the road will be located. Have the surveyor revist the site and flag the centerline of the road--have him shoot station/offset topo from daylight-to-centerline-to-daylight. This should help you develop a tighter FG model and allow you to obtain cut/fill/net, confidently.
Good luck.
H.