Esri Mapping Center - Ask a Cartographer

Merging multiple shapefiles into a single shapefile

August 12 2010 | 4 comments
Categories: Map Data

Hello, I have multiple shapefiles of underwater forms (coral reef, outcrop, sandflat, etc) that I would like to combine into a single shapefile. This would make the data easier to manage and I would use a column in the attribute table to delineate each form, rather than have each be in a separate shapefile. How would I go about doing this? Thanks.

Mapping Center Answer:

First, all the data have to be of the same type (e.g., polygon). Then you can use the Merge tool (ArcToolbox -> Data Management toolbox -> General toolset) to combines your multiple input datasets of the same data type into a single, new output dataset. You could also use Append, but the Merge tool has the advantage that it creates a new dataset from all the combined data. In contrast, Append appends multiple input datasets into an existing target dataset.

But is it really a new shapefile? posted by Britt Bluemel on Jan 11 2011 4:03PM

Hi,

I'm using the Data Management > General > Merge tool to combine many different mapsheets together (just for drainage). The merge works fine, but it's really slow to load/unload, and still draws the new merged rivers as individual mapsheets (but they all fit together and have matching attributes in the end).
My question is - is the merged layer really a true merge and a new file, or a file copying the source location of the original smaller files? Hence the slow, piece-meal loading...

Thanks in advance for your help :)
Britt

New file posted by Aileen Buckley on Jan 11 2011 4:32PM

It will be a new file -- and because all the features will now be in that file that could easily explain why it takes so long to "load", as you say. You should be able to verify this by looking at the total number of records in the attribute table -- it should equal the sum of all the features in the data sets that were input during the Merge function.

Merging multiple shapefiles into a single shapefil posted by Michael Sexton on Jan 22 2012 7:11PM

I have a query about this issue.
I have hundreds of individual shapefiles that I want to merge into a single shapefile.
How do I choose all of them in one go?
It seems to me that I have to click on each of them in turn. I can't get the Shift or Control keys to work as one normally gets using Windows applications.

Is ther a simple method?

Thanks

Mike Sexton
Geoscience Australia

re: Merging multiple shapefiles into a single shap posted by Rajinder Nagi on Jan 23 2012 10:54AM

If your shapefiles are all in one folder, you should be able to select all of them using Shift key. The Merge tool help is here:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//001700000055000000

In the case where each shapefile is in a different subfolder, please refer the previous answers here and use the script provided (you may need to modify the script based on your needs):
http://mappingcenter.esri.com/index.cfm?fa=ask.answers&q=1682
http://mappingcenter.esri.com/index.cfm?fa=ask.answers&q=1716

Hope this helps!

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