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Re: BP8 (web friendly geometries) - compactness, compression, simplification

From: Clemens Portele <portele@interactive-instruments.de>
Date: Thu, 9 Mar 2017 18:01:38 +0000
To: Jeremy Tandy <jeremy.tandy@gmail.com>
CC: "andrea.perego@ec.europa.eu" <andrea.perego@ec.europa.eu>, "Linda van den Brink" <l.vandenbrink@geonovum.nl>, SDW WG Public List <public-sdw-wg@w3.org>
Message-ID: <DEA787D3-AB6E-4F9E-A3B7-1CEB2CEEC4ED@interactive-instruments.de>
I agree, Jeremy.

Related to generalising geometries with Douglas-Peucker or similar, this is also something that can be easily supported via a data acess API by specifying a parameter that expresses the resolution of the map used to display the data in the client. The next version of WFS will support it ([1] is the public change request) and ArcGIS supports it for some time [2], too. In my view, this capability can be considered a best practice. If we have text about this in BP8, maybe we could add a reference to it in BP11.

The WFS implementation of my company also supports such a capability, but currently we use a custom HTTP header as a work-around as the WFS query schema does not support this yet.

Vector tiling is another possible approach to packaging a spatial dataset more "Web-friendly", if map display of the dataset is the main focus. The de-facto standard is [3].

Clemens

[1] https://portal.opengeospatial.org/files/?artifact_id=43079
[2] https://blogs.esri.com/esri/arcgis/2011/06/13/feature-layers-can-generalize-geometries-on-the-fly/
[3] https://github.com/mapbox/vector-tile-spec

On 9 Mar 2017, at 17:38, Jeremy Tandy <jeremy.tandy@gmail.com<mailto:jeremy.tandy@gmail.com>> wrote:

Hi Andrea - it just occurred to me that we're missing a topic in BP8 concerning making geometries "friendly" for the Web.

It's not just about the format(s) we use, it's also about providing geometry objects that are of a size that user agents can handle. (this [1] example provides a nice illustration)

I recall that the Geonovum testbed topic 3 covered this issue; see here [2]

What do you (& others) think?

Jeremy

[1]: https://bost.ocks.org/mike/simplify/
[2]: https://github.com/geo4web-testbed/topic3/wiki/Performance-%26-data-compactness
Received on Thursday, 9 March 2017 18:02:17 UTC

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