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Create contours from DEM in Manifold in FEET

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#1
ErinGreb

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OK, maybe I'm just missing something obvious...

I imported a DEM into Manifold, and want to create contours in feet. It seems to only give me meters as an option?? Any advice on how to change units to feet?

Thanks!!

#2
James Hines

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A simple formula using an SQL script would be:

SELECT ID, [ELV(m)] * 3.280833 AS [ELV(ft)] FROM FNP_ELV

To break it down:

SELECT {Identification column}, [{the column that contains the values in metres}] * 3.280833 AS {[a new column in the new table]} FROM {the drawing or selected table containing the values]

Trying to explain this: in SQL I've created a simple script to change the values in metres to feet thanks to an online units conversion tool. The main problem here is that while I have retrieved the values it creates a new table that is not connected to the drawing, but that's not much of a problem. One thing I will say is that make sure you add a column that can be matched to the data in the original table otherwise the work is useless. In the case of this example I've used the 'ID' column as my field to match the new table to the old table. In effect you will be required to create a relationship. So my solution goes as follows:


right click mouse in the project pane > create new SQL script

write down: SELECT ID, [ELV(m)] * 3.280833 AS [ELV(ft)] FROM FNP_ELV (make changes as necessary)
run

edit > select all
ctrl-c
paste as new table
goto the table of the drawing
and I think you know how to do a relationship so just join the new table onto the olf one & then you should have the values in feet

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#3
Charles Syrett

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Very full reply from James!

I asked this same question to the Manifold Forum a few years ago, and was told:

One easy way is to use a surface transform.
Use the surface transform command and highlight the surface you want to transform and divide by .3048 i.e [surface name]/.3048
Check the save result as new component box and then you will have both the new surface in feet and the old one in meters.


Another thing: you can set your units so that everything is in feet, by changing to Use English Measurement Units in Tools Options.

Last tip: Next time, write to the Manifold Forum. My experience is that whatever the time of day, you'll get answer(s) within the hour. These Manifold users are in every time zone, and apparently a lot of them don't sleep. :rolleyes:

Charles Syrett
Map Graphics
http://www.mapgraphics.com

#4
ErinGreb

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Thanks! I am relatively new to Manifold, and now realize I've got a lot to learn... I will certainly check out the Manifold forum. Thanks for the tips!

#5
BCowper

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To do this in a SQL query you need to use an Update query not a Select query. Here's the SQL code

[codebox]--SQL UPDATE [Surface] SET [Height (I)] = [Height (I)] * 0.3048[/codebox]

Replace Surface with name of the surface you want to convert to feet, preferably a copy of the original.

Current software used: ArcInfo 10.1 (Spatial and 3D Anaylst), Manifold 8.0 Ultimate x64, AutoCAD Civil/Map 3D 2011 x64.





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