topic Re: Tree coding for survey automation in Civil 3D Forum

Tree coding for survey automation

Anonymous — Thu, 23 Jun 2016 19:17:58 GMT

Hi folks

I have some idea what needs to be done but need conformation.

This pertains to how the surveyor needs to code the trees so the tree symbol plots where its suppose to and not down the center of the street as the survey automations has placed them. The surveyor has them coded as "tree 22.5' W". This being the distance and direction from the actual shot.

If he codes them as "Tree H 22.5'" will it place the tree 22.5 feet to the right?

Dave Z.

Re: Tree coding for survey automation

AllenJessup — Thu, 23 Jun 2016 20:12:01 GMT

Well H is the Horizontal offset code. We've never worked with these but you could try it. In my experience the Surveyor usually handles the offset in the data collector so the point is correct when imported. Are you bringing in a point file or a Field Book?

I'm not sure if that will get you exactly what you're looking for:

Horizontal Offset
Specifies the code that indicates a relative horizontal offset for creating a parallel figure starting at the current point, or transitioning to another offset if the active figure has a previous horizontal offset. A value must follow the Horizontal offset code. A negative value offsets the active figure to the left and a positive value offsets the active figure to the right.

Vertical Offset
Specifies the code that indicates a relative vertical offset starting at the current point. A value must follow the Vertical offset code. A positive value is added to the elevation of the current vertex for the active figure and a negative value is subtracted from the current vertex for the active figure.

Stop Offsets
Specifies the code that terminates all offsets on the active figure, and allows only the active figure to be continued.

Re: Tree coding for survey automation

rl_jackson — Thu, 23 Jun 2016 20:33:05 GMT

The codes H V SO are provided for linework and don't control the postion of the point.

In your case your survey needs to use the Data Collector functions, so that the point get placed in the correct position in relation to his baseline, or how ever this location is being accomplished. or shot it directly (prismless).

Tree are not line work and if you intend on using description keys to be a symbol, then you'll have to get the point in the position where the tree is. There are several options for locating item in the data collectors, by offset, right angle etc.....

Re: Tree coding for survey automation

Anonymous — Thu, 23 Jun 2016 20:59:38 GMT

Just what I needed to know. He does it this way because he says he can not get a shot next to the tree because of the gps.

So if I understand you right. When he is standing in the middle of the street and gives me a distance to a tree he needs to code it thru the data collector.

Thanks I will have him figure this out.

Re: Tree coding for survey automation

rl_jackson — Thu, 23 Jun 2016 22:26:59 GMT

That is correct, there are methods of doing the same with the data collector using GPS, it basically calculates the position of the point based on offsets or direction. It's probably easier locating trees with a total station, but if the canopy of the tree is not to extreme the field crew may be able to get a lock on it with GPS that within a reasonable tolerance.

Using a total station you have more options, with Angle Right (positive or negative) and offsets (positive and negative) ie Positive would increase the angle and/or distance and negative would decrease the angle or distance being stored, and calculate the new position accordingly.

Re: Tree coding for survey automation

Pointdump — Thu, 23 Jun 2016 22:27:30 GMT

Dave Z,

If survey is using Trimble Survey Controller or Access, there's a cool GPS COGO tool which allows you to create the point by standing in the shadow line with a distance offset. (GPS knows what time it is and what direction the sun is casting shadows.) I used to use this all the time for utility poles.

Dave S

Re: Tree coding for survey automation

Pointdump — Sat, 25 Jun 2016 23:53:22 GMT

Dave Z,

Good advice from all here. The easiest way to give you a position on the tree is for survey to use the COGO offset routines in the data collector. Depending on the tree, of course, and how it casts a shadow, here is my favorite in Trimble Survey Controller/Access:

Dave S