How to reduce the size of a contour shapefile?

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07-22-2017 07:56 PM
RickCheney
Occasional Contributor II

I am using the latest version of ArcMap for desktop.  I have a shapefile which is contour lines.  I have two shapefiles for adjacent areas of a map.  One of the shapefiles has double the number of contour lines as the other shapefile.  I understand that I can display a reduced number of contour lines by using a definition query, but I would like the actual file to contain fewer lines and be more similar to the other shapefile. Any advice on how to do this is greatly appreciated.

The shapefile I want to reduce contains 673,835 lines in the attribute table and is 125 MB

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AbdullahAnter
Regular Contributor II

However contour lines are not same values, they must not intersect each other.

but I see in your picture they do.

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AbdullahAnter
Regular Contributor II

there is easy method, just Use Join in ArcGIS map for the layer that you want to reduce.

and make join fields for two layers are elevation field , and check on keep only matched records.

and you will get what you want. so you can export them or something else.

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RickCheney
Occasional Contributor II

I can try using Join if the data matches well enough, the rows in one attribute table are in the intervals below

1250
1260
1270
1280

and the rows in the other table are in intervals as below

1247
1280
1312
1345

AbdullahAnter
Regular Contributor II

don't try this, I thought it is as:

10

20

30

40

and other

20

40

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RickCheney
Occasional Contributor II

Thank you Abdullah for all your help.

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GerryGarza
New Contributor III

Hi,

Since it appears that you are working with two different coordinate systems, I would convert them back to raster DEMs. Then, use the 3D analyst extension to re-contour them exactly with the parameters you need.

RickCheney
Occasional Contributor II

Thanks for the help Gerry.  I downloaded the data as shapefiles, one from an American source and the other from a Canadian source.  I don't have raster or DEM data for this map because the map will be used on GPS only.

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