Topic: Working with contours on C3D surface

[nlund1972]

Is there a way to manually adjust contours on a C3D surface?  Can the surface be exploded, contours adjusted and then rebuilt as a new surface?  The problem I have is that I don't have enough survey information and I don't have access to a crew to retreive additional information.  So, what I would like to do, is to manually adjust the contours to create a new EG surface.

[dfarris75]

Can you elaborate on what needs changed? Maybe post a screen grab of the site and note where you want to change it and why?

[mjfarrell]

Nate,

This would suggest that your download the USGS quad map for the area your site is in, and use the extra data from there.

OR

simply draw a feature line @ or near the EG elevations that you do have, outside the area where you do have data, and include that feature line data as a breakline in your surface and it will extend to your new FAKE feature line, and that should hold you until you get survey data.

[nlund1972]

I will not be getting any more surface data and the quadmap doesn't have enough detail for what I'm looking for.  I am using 0.1' contours to delineate features on the surface and need to figure out how to generate the information, without physically retreiving the information.

[nlund1972]

Elaboration:

I have an area that I am trying to obtain a storage volume in.  The problem that I am running into, is that the surveyors didn't get enough information in key locations to obtain a reliable tin.  I have a couple of islands in the middle of the area, the surface is ignoring portions of the curbing, due to a lack of survey information.  If I could retreive the contour information in a fashion that I could modify (digitize, etc.) the contours, I could force the tin to model the actual surface more closely.  So, what I am looking for, is a way to extract the contours from the surface to grip edit them and then recreate the tin based on the new (modified) contour information.

[mjfarrell]

So you aren't trying to EXTEND the data beyond where you have data, you want modify the data you do have.

A) Edit or Add points to the surface under the Surface edits function, or add, or edit breaklines that create the bad data.


B) Please do not do this this way


Surface>>Utilities>>Extract objects from surface (Contours) and then manipulate those polylines to death
Then build your faked surface from the manipulated data.

[nlund1972]

That is where I am heading though.  The information that I am trying to generate is so sparse and incompatible with the area that I am working with, I don't know what I would establish as elevations on points and no real good way of adding a breakline, for the same reason.

[mjfarrell]

That is where I am heading though.  The information that I am trying to generate is so sparse and incompatible with the area that I am working with, I don't know what I would establish as elevations on points and no real good way of adding a breakline, for the same reason.

I'm curious, if you do not have enough information to alter this surface to make it 'correct'; how do you know it is wrong?

[Dent Cermak]

Faking interpolated ponts on a surface built on a 0.1' contour interval is putting your tush in harms way. If the contour interval is this tight, someone expects real accurate results. They will not get this with fudged data.The safest way to do this is send the crew back out for the shots, but if that is not possible you can interpolate new points based on the existing shots. But you better know the exact lay of the land and be REALLY experienced in dragging contours. If the answer to either of those questions is not a hearty "yes" then someone is strolling in harms way. And if a dispute arises over the calculated volumes you will be in a real bind. Remember, there are only two ways to do a job for a client. The right way or the wrong way. Your choice.

[scout]

Elaboration:

I have an area that I am trying to obtain a storage volume in.  The problem that I am running into, is that the surveyors didn't get enough information in key locations to obtain a reliable tin.  I have a couple of islands in the middle of the area, the surface is ignoring portions of the curbing, due to a lack of survey information.  If I could retreive the contour information in a fashion that I could modify (digitize, etc.) the contours, I could force the tin to model the actual surface more closely.  So, what I am looking for, is a way to extract the contours from the surface to grip edit them and then recreate the tin based on the new (modified) contour information.

I agree with the other guys that I find it a bit counter productive to fill in the gaps left by survey data this way (especially when doing volumes).

That being said you can do what you want a few ways.

If you choose Surface>Utilities>Extract Objects from Surface, you can extract all (or some) of your contours. They come out as plines with elevation. You could grip edit them then add them back to the surface as contours, and your tin should adjust to add that information.

[mjfarrell]

that is the same solution posted as option C above

[scout]

that is the same solution posted as option C above

so sorry! my reading glasses must need to be cranked up.