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Intersect of data (both spatial and temporal)

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04-27-2016 10:04 AM
JohnFrye
Deactivated User

I have a data set that is point data. This point data has an occurrence time (YEAR MONTH DAY HOUR MINUTE). I want to find which of these points "intersect" both spatially and temporally with another data set that is polygon data. For example, the point happened inside the polygon and at the same time the polygon was active. The polygon data set has a start and end time in the same format as the occurrence time of the point data.

I have multiple years of data and running the spatial intersect gives we when the points and polygons intersect but I need to further discriminate by time as well.

Any thoughts or guidance on if this is possible and the best way to approach this problem would be appreciated.

7 Replies
DanPatterson_Retired
MVP Emeritus

I don't suppose you have enough data temporally to make this useful Create Space Time Cube—Help | ArcGIS for Desktop

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JohnFrye
Deactivated User

To clarify what I am looking for in the end...the end goal is to have a list (or a layer created) of points that did not occur within a polygon and a list (or layer created) which polygons had no points fall within them; from both the spatial and temporal dimensions.

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DanPatterson_Retired
MVP Emeritus

one simple way is to do select by location for the points in the polygon, then switch the selection, right-click, data export and you have your points not in a polygon.  that is the basic principle, others options would weigh time to complete manually vs fancier implementations

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JohnFrye
Deactivated User

I need the time component figured in that as well. I can easily get the spatial aspect, it's the time component I am stuck on. I have 225,000+ points and 250,000+ polygons so doing this manually is not an feasible.

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DanPatterson_Retired
MVP Emeritus

have you got moving or disappearing polygons?  you mention the polygons were 'active' which to me suggests they were either there then not, or it is a moving object.  In this mix you have points which may or may not be in a moving target.  Perhaps some clarification might help.

I view your data set as a multidimensional array, which is bounded by an extent (the X and Y dimension).  Over time (the z dimension if you prefer) you have points and polygons which are in a location or occupy space.  The points can be represented as an array with the same spatial and temporal dimensions as the polygons.

In essence, you are looking for the non-intersection of the points in the polygon for every time slice between both arrays.

For example, if you are only interested in a point not being in a polygon at a point in time, then this is simply a masked array operation, whereby the point locations of interest are only those not in the mask (ie not in the polygon) at that point in time.  intersecting multidimensional arrays is generally work done outside of arcmap (in my opinion), but the space-time cube facilitates this to some degree.

btw intersecting 225000 points in 250,000 polygons is no big deal, it is the time slice that adds to this dimension... or do you have X points vs Y polygons at various time Zs.

So any insight as to the intent and your data structure would be useful to narrowing the options down.

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AbdullahAnter
Honored Contributor

there is so easy solution,

just do spatial join for points feature class the have an occurrence time field with the polygons that have start time and end time, and make " it falls inside" checked.  now you get the spatial join. to select  temporally of point feature. use select by attribute as:

[point occurrence time field ] > [polygon start time field ] And  [point occurrence time field ] < [polygon end time field ].

then you will get both spatial and temporally intersect.

thanks

DanPatterson_Retired
MVP Emeritus

John...moving the thread to Analysis​ to facilitate commentary, rather than have it languish in the generic Community Help pool

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