Change point feature class to multipoint

[DiegoBrenes1]

I have a point feature class where I record projects' (clients) locations and several other attributes.  So far I have been using it to record just one location per project. However, in some instances a project may have multiple locations, which I would like to start including. Some features would have only one point and others would have multiple points. Is it possible to convert my existing point feature class to a multipoint type? I tried through Properties of the feature class in ArcCatalog, but it seems that the Type can not changed (it is grayed out). I use ArcGIS Basic 10.3.

Thanks for any help.

[DarrenWiens2]

I don't believe you can directly change the data type from point to multipoint, but you can create a new feature class of type multipoint, then copy/paste the point features from your point to multipoint feature class. You can then transfer the existing point attributes to the new multipoint geometries using Spatial Join.

* I'm not sure if there is a single tool that will combine the above steps. I would have guessed Append, but that does not work between point to multipoint feature classes.

[DiegoBrenes1]

Thank you Darren.  Will try that

[JoeBorgione]

I think you'll need an advanced license for that tool; you might ask your colleagues with that license if they can do it for you.

[DiegoBrenes1]

Thank you Joe

[ChadKopplin]

As best I can tell this is not an option.  A person is able to go from a multipoint to a singlepoint, because they are making one point represent the many.  In what you are trying to do, you are trying to go from one point to many.  There would not be away to going from one point to many if the other points did not all ready exist with in the shapefile of feature class.  You can still add the other points into your feature class.  If you have them in an Excel spreadsheet, dbf, or csv (as examples) you could load this file as an event theme, convert it to a new shapefile and copy/paste the other locations into your point file.  I hope this helps.

[DiegoBrenes1]

Thank you Chad.  For the existing points, they will remain as one point. It is for new features that I will create within the same feature class that I want to have the option of having either 1 or several points.

[VinceAngelo]

It is for new features that I will create within the same feature class that I want to have the option of having either 1 or several points.

Unfortunately, this is not possible.  Some storage formats (you didn't say which one you are using)  implement this differently than others, but you really will need to copy the existing feature class to a degenerate multipoint feature class.  Note that the storage may be significantly larger (e.g. ~2.3x in the .shp of a shapefile - from 28 to 64 bytes per feature) and the spatial index for multipoints is much less efficient than for points, so if there are a large number of features (100k+), you will see measurably slower spatial query performance with single-part MPOINT features in a MPOINT layer (vice POINT data in a POINT layer).

- V

[DiegoBrenes1]

Thank you Vince, this is very helpful.  I am using a File Geodatabase.  Since this feature class in my database is rather small, no more than a few thousand features, I may not have performance issues. I'll try this route.

[VinceAngelo · Accepted solution]

I found a shortcut to make multipoints from points: use ArcToolbox -> Data Management -> Generalization -> Dissolve, choose the point feature class for input, reference a new "m" feature class (e.g., points5 -> points5m), select all attributes (only include the old rowid if you need it to keep features unique) , and make sure the "Create multipart features" checkbox is ticked.

- V