topic Re: Select by Location within a Location? in ArcGIS API for Python Questions

Select by Location within a Location?

RussBryant — Mon, 07 Aug 2017 18:11:08 GMT

Hi there,

I am trying to create these core areas within hexagons. To start I need to find any 50+ acre polygons that share their boundary with any other polygon within individual hexagons. So its essentially a select by location where hex ID is equal to hex ID, but this has to be repeated/analyzed for each individual hexagon the polygons inside them. Any thoughts of questions would be helpful!

Thanks

Re: Select by Location within a Location?

DanPatterson_Retired — Mon, 07 Aug 2017 19:37:19 GMT

The default is to make a new selection...

Once a selection is made, it will be used in subsequent attribute or spatial selections that have a 'select from current selection' or similar option

Re: Select by Location within a Location?

RussBryant — Mon, 07 Aug 2017 20:05:55 GMT

Thanks Dan,

And I am familiar with that, just I am trying to replicate this 7,000 times (given I have 7,000 hexagons) so that would be quite tedious. I need to find/create these cores in each hexagon using a more automated method. I am essentially looking for some sort of python script where it would be like

if "corelayer hex id" = "corelayer hex id"

than select layer by location SHARING BOUNDARIES.

Re: Select by Location within a Location?

DanPatterson_Retired — Mon, 07 Aug 2017 20:23:07 GMT

hmmmm a picture might help ... not quite getting the corelayer hex id comparison

Re: Select by Location within a Location?

RussBryant — Mon, 07 Aug 2017 21:13:50 GMT

So the these are essentially 2 layers, a hexagon layer for analysis and a "core layer". The core layer is broken into 2 colors (green and blue) depending on habitat type, but in each of the core polygons is intersected by the hexagon and populated with that overlaying hexagon ID. I am essentially trying to find a 50+ acre green area in each hexagon and everything else that is contiguous/sharing a boundary with it, as long as it is within the boundaries of that associated hexagon and repeat this so on for each hexagon. Thanks Russ

Re: Select by Location within a Location?

DanPatterson_Retired — Tue, 08 Aug 2017 00:00:06 GMT

Some ideas to get started.

First get rid of the small fiddlybits that are less than 50 acres regardless of whether they are solely within or traverse a boundary.

Second, don't you have a geometry constraint? Thickness, width/length perimeter/area ratio? Some of those polygons are pretty irregular in shape.

Third, do you need all the candidates? or the biggest one that is mostly inside one hexagon? possibly, split the green polygons by a polyline version of the hexagons and redo the area calculation to dump even more.

Fourth, from step 3, you could summarize the green area per hexagon and keep the most green

That's all the ideas for now