[R-sig-Geo] Analysis of sub-districts border changes over time

[Roman Luštrik]

Assuming polygon IDs were kept from 1981 to 2011, you can just compare
areas. If area changed, there's a good chance the border changed as well.
The caveat is that if the border changed, there's also a chance that the
area was preserved. I would inspect each (pair of) polygon visually to make
sure.

Another way would be to compare if borders still overlap. Package rgeos has
many functions to test these sort of cases, including point in polygon.

Cheers,
Roman

On Thu, Mar 3, 2016 at 10:45 PM, Rami Krispin <rami.krispin at gmail.com>
wrote:

> Hello Everyone,
>
> I am trying to identify changes over time of sub-district in Andhra Pradesh
> (a state in India). My data contains 4 shape file from a different period.
> At 1981 there were 320 sub-dist and over time there were splits of the
> state sub-dist which increase to 1128 at 2011.
>
> I am trying to find how the border of each sub-dist change over time (stay
> the same, increase, split etc.) using the centroids and area of each
> polygon.
>
> Is there a way to compare between 2 shape files and to check how the
> polygon change?
>
> Also, does any one know how can I check whatever the centroid is
> inside/outside the polygon area?
>
> Thank you in advance,
> Rami Krispin
>
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-- 
In God we trust, all others bring data.

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