Grouping polygons

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07-24-2014 08:02 AM
KevinWilliams
New Contributor

I'm trying to help someone with their mxd and I'm not sure why I can't recall how to do what is needed. I am attempting to "group" polygons within the mxd. They currently have several polygons, for instance police beats, but would like to group them by a certain attribute for later use. The catch is that they don't want to remove them from their current gdb into a separate feature dataset or feature class, which leads me to grouping them within the mxd. Unfortunately, this eliminated selecting by attribute and creating a new layer. Is there an alternative method to "grouping" certain polygons based on an attribute within the mxd?

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8 Replies
IanMurray
Frequent Contributor

Hi Kevin,

Actually, creating new layers wouldn't affect your gdb feature class at all.  Layer's in the TOC are merely references to your existing data, so when you are creating layer files from them, you aren't actually editting or creating new files, just referencing different parts of them.  You can save a .lyr to your harddisk but that just saves the symbology and definitions you assigned that layer, but it won't work without the original data.

Are you trying to "group" for symbology purposes, or would you actually want to aggregate them into single features?  If you want to symbolize the grouped polygons the same, either symbolize them by a common attribute from the attribute table, or you can create a new field to base your symbology off of, and use the field calculator to give all the ones in a group the same value(you would probably have to manually select them).  Then under symbology, symbolize by category and select the filed you want ot base it off of.

If neither of those is what you are looking for, give a little more detail on what you are trying to do and we can probably find a better solution.

Ian

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FilipKrál
Occasional Contributor III

Hi Kevin,

Sound to me like you would like to Dissolve Polygon Boundaries using Symbol Levels: http://resources.arcgis.com/en/help/main/10.1/index.html#//00s500000025000000

I am not sure what you mean by 'group them for later use' so depending on what the later use is, you might need to Dissolve the polygons and so create a new feature class.

Hope this helps,

Filip.

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HemantAngarkar2
Occasional Contributor

Hi Kevin,

I am not sure about the type of grouping you are looking for. From what I understood you want to create groups of feature classes. And apparently one feature class can be in more than one group depending on certain attributes.

I am sure you must have tried selecting desired polygons and grouping them by right clicking. And for new group you can right click on data frame. You can keep one feature class in multiple groups simply by copying and pasting in new group.

It is simple, but I thought it might help.

Hemant A.

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AnnalieseVollick
New Contributor III

Are you trying to make multi-part polygons?

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KevinWilliams
New Contributor

My apologies for not presenting the question as it should have been, but I was simply relaying the information given to me. Like all of you, my mind immediately went in several directions. Unfortunately, working with someone who does not understand Arc and not having a chance to see what she was referencing made comprehending the desired outcome a bit difficult. I appreciate all the responses, and as I mentioned, I suggested several options, but was rebuffed. After a lengthy phone conversation and getting full details, the answer should be overly simplistic.

My understanding is... she has one feature class consisting of 67 polygon features. She categorized these based on a single attribute. She needs to "group" some of these features (for example: Police Beats 100, 101, and 102) into a single category within the main feature class. She wants to maintain the single feature class, but have less categories to work with.

I will know for certain when I meet with her tomorrow, but I believe all she wants is to group values using the symbology tab. My only concern is explaining to her that when someone else adds this feature class to a new mxd, the symbology will not be reflective of her "grouping".

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DanPatterson_Retired
MVP Emeritus

Once the symbology is created, a layer file (.lyr) can be created to retain the symbology of the file.  If working on local disks etc, it is best to house the *.lyr file in the same folder as the originating data

IanMurray
Frequent Contributor

Exactly what Dan said

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KevinWilliams
New Contributor

Sorry for the delayed response, but my meeting was pushed back until today. Just to put this question out of its misery...

I made a copy of her feature class, changed the 'name' field in the copy to her specs, then merged the original feature class with the copied feature class. This allowed her to query based on two separate 'name' fields. For example, one feature class with several polygons. Each polygon had a name ranging from 100 - 410; each polygon is now duplicated within her feature class, but the 'name' can now be identified by 100, 101, etc. but also 1000. Hopefully that makes sense for everyone, because while this was not my preferred method, it seemed to be exactly what she wanted.

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