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ArcMap 10.1 SP 1 License: Advanced

I am attempting to remove overlapping portions of a multipart without going through the steps exporting or creating a layer from each part and clipping individually. I've looked around at various answers, it seems the answer may reside in topology rules. I admit I'm not very familiar with using topology, so I was unsuccessful. In fact it appears my rule was simply not applied. No doubt due to my incompetence.

Is it possible to accomplish some fashion of "clipping" of a multipart polygon with its own parts?

Here is what I'm doing and what I've done; I will wager someone else has done a similar task. The data is wildfire data taken from modis, essentially I am building a progression map using modis data. The data comes as points, I used minimum bounding geometry to convert the data into a multipart polygon using the Julian date from the point data. This works as I don't need dead accuracy for my purposes, it's more of a quantity over quality project. Because the process of min bounding is a bit coarse, as is the point data, I cannot simply subtract the total acres from the previous day to get acres per day. That is the data I am actually seeking. After the minimum bounding I clipped the polygon to the final fire perimeter as the process created some polygon area outside the fire perimeter. This is really where I am stuck.

I've tried some merging and dissolving based on similar questions. Perhaps I'm missing the vision in those as they have yielded nothing useful. I also tried the topology route by creating a gdb. I created topology with a rule of must not overlap for the feature data set, then exported the data from my map into the gdb as a feature class. This didn't appear to do anything, so I'm rather certain I did not do this correctly. I then fumbled around with the topology tool bar with no success. I could do a union and then pick out the issues; this is tedious. I will likely need do this process again in the future, so avoiding tedium is a plus. Ideally I could make a model with the two inputs of modis data and fire perimeter to get at the end result. My model building is another conversation entirely.

Short version: The picture below may help me explain things. The polygon is multipart, Julian day 223 is sitting atop day 224. I would like 224 to not be under 223, essentially it would be clipped by 223. This would carry on through each day.

here is a pic of the map

  • Your analysis may be a lot easier if you did it as rasters. Convert your points to a grid then you can add or subtract? As you say you may be doing this regularly in the future it is worth your time exploring this as some sorts of analysis are a whole lot easier. – Hornbydd Jun 5 '16 at 9:45

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