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Polygon data from elevation of internal points...thousands ...to 3D!?

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Message 1 of 6
Enzdata
797 Views, 5 Replies

Polygon data from elevation of internal points...thousands ...to 3D!?

Hi all. First post ever I think?!! Any help would be massively appreciated.

 

I have thousands of polygons (and circles) which represent 2D foundation detail.

I have XY Location data (XLS, CSV etc) and Z's for the tops and bottoms of all these objects. (and hence, AutoCAD points)

 

I have used SHP data before (for the building footprints, and tops) whereby the top and base data is included in the data and I have use mapimport with change properties to thicken polylines and create quick 3D objects above ground.(This was created by others using a method similar to what I want, but in a competitors GIS...)

 

I need to do the same with the footings...

 

How can I create a "search" that says - for each polygon, look for a single point inside, and report its elevation and attached that to the polygon as data? Or, create a SHP of all these polygons with RL data queried of the internal point.

 

The points arent necessarily at centroid, which could be an issue. (Most are, however)

There is no keyID data between the polys and the points (so data joins wont work)

 

A friend did this very quickly for me in an ESRI Package, surely MAP can do the same!?

 

Map 3D 2012, and a monstrously powerful CAD workstation... just, er, not the knowledge to yet pull this off.

5 REPLIES 5
Message 2 of 6
thepworth
in reply to: Enzdata

start with looking at creating polygon topologies - you can use the elevation points as centroid data to apply to the polygons.  You might have to create several versions for roof elevation / finished floor(s) etc.  then you can export the topology to a .sdf or .shp with the elevation attached from the node.  look in help for the different topologic analysis functions in Map, such as identity, union & intersect.

 

HTH,

 

TdH

Message 3 of 6
Enzdata
in reply to: Enzdata

"you can use the elevation points as centroid data to apply to the polygons"

 

please explain...

 

I should explain that I have been creating polygon and point topologies, but I think I am missing a step somewhere...

 

Did I say...None of the objects, as yet, have any data attached... I suspect that may be part of the problem (the points elevation is the data)

Message 4 of 6
thepworth
in reply to: Enzdata

It may require some fiddling - such as exporting the points to a .SDF and selecting "object data" with the export to get the elevation from CAD points and a few steps.  I'll see if I can come up with a reasonable workflow and update - been sick the past few days & this one looks like it should be interesting (not necessarily simple, but I think I can get it to work)

Message 5 of 6
thepworth
in reply to: thepworth

O.k so it seems that I can simulate & get things to work if I create a rectangle (polygon) and put a point inside at a non-zero elevation.  Then, if I create a .SDF file from the point layer (MAPEXPORT), from the Export dialog box, go to the "Feature Class" tab then "Select Attributes" and "Properties" then "Elevation" also change the SDF geometry from Point+line+Polygon to just "points"  Now you get a .SDF with points that have the elevation as part of the object data.

 

Then I "MapImport"ed the .SDF & Created object data to get the elevation tagged to each point

 

Then I created a polygon topology & selected the centroids with the object data from the Mapimport above.  Now the object data elevation is tagged to the centroid

 

Finally, from "Create" tab of the Tools Based Geospatial workspace, under "Topology" I selected "Create Closed Polylines" and copy object data from centroid to PLine.  Now I have the centroid elevation tagged to the polygon as object data on a new layer 

 

Does this get you going in the right direction?  Or, does anyone have suggestions to simplify the above?

 

TdH

Message 6 of 6
Enzdata
in reply to: thepworth

Worked like a charm. Thanks.

 

I was doing most of those things, but in the wrong order! I think the key thing was the initial mapexport to points which sorted out the issue. I was trying to do everything in one hit.

 

Cheers. This will save me many, many hours of work!

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