ArcPy: Finding Local Maxima of Groups in an Attribute Table

kevinkent — Tue, 21 Oct 2014 21:10:30 GMT

I'm still a beginner with ArcPy and I'm wondering how I can write a script that can iteratate through a table and find the LOCAL maxima of each group

I've spent a lot of time looking into the arcpy.da.UpdateCursor module but I can't figure out how to go group by group and look at values in more than one row at a time.

Can this even be done? I've also looked at converting the table into a NumPy array but I am also lost there.

I've included this example to illustrate what I'm looking for. I am thinking using the update cursor to change the values of Field 03 from 0 to 1 for the records that represent local maxima would be helpful but I'm sure there are other ways to go about this.

Field 01: Group(Integer)

Field 02: Length(Double)

Field 03: For Flagging desired fields(integer)

ID Field 01 Field 02 Field 03

01 10 07.0 0

02 10 09.0 0

03 10 03.0 0

04 10 11.0 0

05 12 18.0 0

06 12 16.0 0

07 12 02.0 0

08 12 07.0 0

09 12 04.0 0

Results would be:

ID Field 01 Field 02 Field 03

02 10 09.0 1

04 10 11.0 1

05 12 18.0 1

08 12 07.0 1

Thank you for any help.

Re: ArcPy: Finding Local Maxima of Groups in an Attribute Table

DallasShearer — Wed, 22 Oct 2014 12:43:33 GMT

the summary statistics tool may be the easiest for you to implement.

ArcGIS Help 10.1

Re: ArcPy: Finding Local Maxima of Groups in an Attribute Table

kevinkent — Wed, 22 Oct 2014 21:04:59 GMT

Thanks for the suggestion but as far as I know summary statistics would only work if there was one maximum for each group. Some groups have multiple local maxima that I need to find also.

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ArcPy: Finding Local Maxima of Groups in an Attribute Table

Re: ArcPy: Finding Local Maxima of Groups in an Attribute Table

Re: ArcPy: Finding Local Maxima of Groups in an Attribute Table