Comparison of Topographies

[shershahbacha9]

Hello !!

I created same topography by different means and need to compare it visually with accurate topography in revit which i already have. I want to compare it like kind of having grids and place two sites over each other so could see along the profile how much deviation is from original topography. Is it possible ? Can anyone help.

below is screenshot of how my topography looks like

[shershahbacha9]

i want it to do as you said with grid lines. This is my purpose. Yes i created revit topography of an area from surveyors point file which is our standard with which we have to compare other topos of the same place but by different methods from different sources. I actually have to see topo created by which method is closely following the standard one from surveyors file. Then i have to use that method which gives more accurate topo. 

And yes i want it to compare the same , like by grid lines and elevation profile

[shershahbacha9]

Can you explain your method in a little more detail please

[barthbradley]

You have an actual point file from a Land Survey? 

[shershahbacha9]

not actually a point file, but a cad file. There points along with its elevation written. So in Revit i put topo points manually on them and giving them their respective elevations

[ToanDN]

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@shershahbacha9 wrote:

Can you explain your method in a little more detail please

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"Now, to compare them visually, link each of the 'toposurfaces' as an in-place mass or a generic model (assuming they are DWGs), move them as close as possible to the 'accurate' one, create a bunch of grid lines and create Elevation > Framing elevation and tick Attach to Grid then select the grid lines to create the views.  Open each view and compare the cut profiles of the topos and write your report."

Which steps of the above that you need more details?

[barthbradley]

What is the source for the CAD file? An actual Land Survey?  If so, those points represent more than just elevation data. They represent x and y data as well -- which is critical information.   

[shershahbacha9]

yes , you are right . they represent x and y as well.

[MostafaElashmawy]

I think that you need to read more about google maps and Google earth topography and how accurate they are.

Anyway, the wokflow that I discribed is the nearest workflow required by the question. 

Try to focus on helping people instead of mocking methods that you don't know.

[MostafaElashmawy]

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[MostafaElashmawy]

If you aim to make a grid showing the levels, Civil 3D will be your best option.

Revit can compare only by any of below methods and all depends on placing the Topographies at their correct coordinates:

1- Fill and cut quantities.

2- making sections and compare the profiles.

3-compare visually.

4- cross checking using spot elevation.

[shershahbacha9]

Thanks mostafa brother, but i need to do it in Revit and i will try with these. Right now my headache is giving correct coordinates and level, which i have no idea and to search it . 

[MostafaElashmawy]

As continuity to what  @barthbradley  said, usually the points in CAD survey files have X,Y,Z. select a point and check if these X,Y,Z are correct or not.

[shershahbacha9]

for survey points file , i could know x,y and z there but by other methods using google earth for example , how would i know its coordinate system and levelling it

[MostafaElashmawy]

open the cad file, select any point and check the properties and give me a screenshot.

[MostafaElashmawy]

and one question: I understand that you have a cad file with points for a Topo. what about the other one, do you have another Cad file for it?

Can you share them?

[MostafaElashmawy]

If you insist on making the grid in revit, check below video for reference. I did an example but it's very primitive. Not sure if that is what you are looking for. you can do this grid in both files to be able to compare.

[barthbradley]

The single most important question is:

Is there a known site feature they ALL share that you know the real world x, y and z coordinates  of -- such as a geodetic marker? If you can find THAT point on each topo, then you have a shot at accurately aligning the topos for "comparison" -- assuming you can identify true north on all the topos.  Otherwise, you are just guesstimating.   

[shershahbacha9]

they both have same boundaries. I do not have to it by exact coordinates method. i want to do it manually. for example i link other topography to ist one and manually place same corner of both topographies together. but i want kinda grid method that i actually show that how much difference is coming along its length

[shershahbacha9]

instead of exporting one topo to Cad and then creating topo from it again in other file, can i link one revit file to other ? Also for visual comparison it can be done , but how can i compare with some values For example grid lines having elevation values etc

[shershahbacha9]

i am also doing the same. The topography of the same plot by different means and comparing it to the one by land surveyor. I can compare it visually like you guys told about phases etc but how can i compare them with some numbers associated and quantify it . e.g some gird lines having elevation values. 

Also the two topographies have exactly same boundaries (one from land surveyor and from Google earth) but by other sources like plugin CADtoEarth, plexEarth and sketch up , they dont give exact boundaries but with some extra areas all around and dont know how to put them at the same point in other topographies from surveyor and Google earth