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Augmented diffs: Reduce size by filtering by action #357

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ltog opened this issue Jan 2, 2017 · 6 comments
Open

Augmented diffs: Reduce size by filtering by action #357

ltog opened this issue Jan 2, 2017 · 6 comments

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@ltog
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ltog commented Jan 2, 2017

I have a usecase for augmented diffs / the Overpass API, where I'm only interested in OSM objects respectively tags that have been added or changed. I'm not interested in objects/tags that were deleted. When I call api/augmented_diff? I receive an augmented diff with usually some tags <action type="delete"> that I will never use.

How about a new parameter actions= (besides id= and bbox=) where one can limit the types of action that the Overpass API will return, e.g. actions=create,modify? That would reduce the amount of data that needs to be transferred from server to client. I also guess it should not be that computationally expensive to do the filtering.

@mmd-osm
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mmd-osm commented Jan 2, 2017

As we're currently precalculating diffs and only serve cached results as a file for download, any additional parameter would interfere with that approach. If download size is an issue, did you already consider using HTTP compression instead?

Caveat: Augmented diff are impacted by a systematic issue at this time. Be sure to check #346.

#154 is related (augmented diffs leverages adiff)

@ltog
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ltog commented Jan 11, 2017

If download size is an issue, did you already consider using HTTP compression instead?

@mmd-osm : With compression you mean setting a header like Accept-Encoding: gzip, deflate in your HTTP request?

@mmd-osm
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mmd-osm commented Jan 11, 2017 via email

@ltog
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ltog commented Jan 11, 2017

@mmd-osm : Yes, I do that already...

@drolbr
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drolbr commented Jul 18, 2018

See blog

@ltog
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ltog commented Jul 18, 2018

@drolbr : The link you mentioned didn't work. You probably meant https://dev.overpass-api.de/blog/sliced_time_and_space.html ?

Thank you for your continual efforts!

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