Spatial Data on the Web Working Group Teleconference

05 Aug 2015

See also: IRC log


Kerry, stakagi, kostas, aharth, Linda, Payam, Kostas, ChrisLittle, phila, SImonCox, billroberts, Alejandro_Llaves, frans, BartvanLeeuwen, AndreaPerego
Lars Svensson, Rachel Heaven, Ed Parsons
andreas harth


<trackbot> Date: 05 August 2015

<kerry> scribe: andreas harth

<kerry> scribenick: aharth

<kerry> http://www.w3.org/2015/07/29-sdw-minutes.html

<Payam> +1

<phila> PROPOSED: Approve last week's minutes

<Payam> +1

<Linda> +1

<kerry> +1

<Alejandro_Llaves> +1

<BartvanLeeuwen> +1

<phila> RESOLVED: Approve last week's minutes

<billroberts> +1

<ChrisLittle> +1

kerry: patent call

<phila> Patent Call

<phila> kerry: This is the patent call that satisfies OGC process. It's important that any patent claims are declared

<phila> ... Please remember to type present+ and your name

<phila> ... this records your presence in the minutes

Welcome new members

<phila> kerry: Invites kostas to introduce himself

kostas: university of surrey

<phila> kostas: I'm a KTP associate... at Univesity of Surrey (works with Payam)

kerry: welcome Satoru Takagi, editor of svg recommendation

<phila> kerry: Also welcoms Satoro Takagi, editor an an SVG spec

<stakagi> Hello!

Use Cases and Requirements: Editors' stocktake report

kerry: update on document
... frans and alejandro are both here

<Frans> http://w3c.github.io/sdw/UseCases/SDWUseCasesAndRequirements.html

frans: url of current version of the document
... first public working draft has been published a while ago
... with feedback on the public comments lists
... some issues left, issues are labelled in current version of document
... some recent changes not related to tracked issues
... two new chapters have been added

<Frans> a new chapter: http://w3c.github.io/sdw/UseCases/SDWUseCasesAndRequirements.html#RequirementsByDeliverable

frans: one extra chapter with a summary of requirements per deliverable

<Frans> http://w3c.github.io/sdw/UseCases/SDWUseCasesAndRequirements.html#DeferredRequirements

frans: another extra chapter on requirements that are deferred to some later time
... another global change relates to slight change of wording (standards -> recommended way)

<kerry> alejandro: we are wroking to close the issues in the tracker still from barcelona

<kerry> .... ideally now looking for external feedback

<Linda> What was Frans saying about CRS requirements?

alejandro: after public working draft we'll get external feedback that will help to refine requirements

<kerry> ... we should try to extend the description of requirements

<Frans> For CRS requirements a separate meeting or teleconference is considered.

alejandro: we should try to extend the descriptions of requirements with examples

<kerry> ... with examples and clarifications

kerry: any more questions on the use case document?
... discussion on crs in particular delayed a bit to give people a chance to comment

SVG for spatial: Presented by Satoru Takagi by invitation (confirmed)

<ChrisLittle> kerry you kept droppping out on audio - is that me or you or all?

<stakagi> Thank you very much for inviting to conference.

kerry: scalable vector graphics

<stakagi> First, I would like to introduce the strategy of the standardization activity of mapping on SVG2.

<Linda> Good audio here Chris

<stakagi> I want to fuse mapping with a web browser. Because I think mapping is essential function for WWW.

<kerry> stakagi, your turn to speak please!

kerry: satoru is not on webex but will do presentation on irc

<stakagi> Yes I am IRC only

<phila> we're reading you stakagi

<stakagi> SVG2 is under standardization as a succeeding standards of SVG1.1 snd edition. Probably, it is standardly implemented in web browsers.

<ChrisLittle> * thanks linda - i'll move nearer my router

<stakagi> https://svgwg.org/svg2-draft/

<stakagi> We set some policies in standardization of the spatial information on SVG.

<stakagi> Provide a certain effectual result to the drawing function by the browser of SVG.

<stakagi> That is, don't be satisfied with a mere metadata. The functionality should be implemented as a native functionality of all the web browsers. Besides, we consider that value of Web is concentrated to the web browsers.

<stakagi> The functionality needed for Web Mapping should turn into a native functionality of a web browsers.

<stakagi> That is, the functionality of Web Mapping should be offered without massive web Apps.

<stakagi> We consider that massive Web Apps does not have a not much good effect on the interoperability of a data. Sometimes, it may produce a data silo.

<stakagi> On the other hand, we believe that the functionality essential to such a mapping should not be a functionality only for a mappping.

<stakagi> That is, we consider that the functionality it is often used by mapping should be generalized so that it may be used also other than mapping.

<stakagi> It is because it promotes the native implementation to web browsers. These are the policies which we (KDDI) decided.

<stakagi> So far, are anything a question and comment ?

<phila> We're reading your words, stakagi

<stakagi> Yes

<phila> Please continue, I am likely to have questions later

<stakagi> Yes continue.

<stakagi> First, we enumerated needed functionalities on the mapping for us and submitted the documentation which summarized it as a first stage draft specification to W3C as member submission.

<stakagi> http://www.w3.org/Submission/2011/04/

<stakagi> This is our member submission.

<ChrisLittle> +1 to general mapping migrating natively to browsers

<stakagi> Thanks Chris!

<stakagi> This submission includes global coordinate systems ( general purpose CRS)

<Frans> I like the idea of browsers natively recognizing spatial data and being able to display it.

<stakagi> and Tiling and Layerling.

<Frans> Satoro, Well Known Text (WKT) is a popular format for geographic geometry. Are you looking at automated transformation between WKT and SVG?

<stakagi> SVG has metadata framework

<ChrisLittle> The OGC has active work in progress on layering and tiling. Is KDDI a member of OGC?

<kerry> s/nw/now/

<stakagi> No, currently KDDI is not OGC member.

<stakagi> over 15 years ago KDDI was OGC member.

<ChrisLittle> Joan Maso is Chair of Web Map Tile Service Standard WG, and I Chair Web Coverage Tile Service SWG

<ChrisLittle> +1 kddi OGC member!

<stakagi> but past OGC's member is not interested in our work.

<ChrisLittle> past is past, now is now

<stakagi> Yes^^

<joshlieberman> I believe that Carl Reed, former OGC CTO had a fair amount of interaction with the SVG standards working group, but it lapsed.

<phila> And W3C is the home of SVG, making things first class citiznes of the Web etc. Shall we go on ChrisLittle?

<joshlieberman> Good to take up again, perhaps by recognizing some mapping use cases, e.g. dealing with geographic projection and feature attributes

<phila> Do you have more stakagi or should we ask more questions?

<stakagi> Do you intered in Tiling architecture on SVG?

<kerry> anyone for tiling?

<phila> Isn't the point of SVG for maps that we can do away with tiling?

<Frans> I think vector geometry tiling is a hot topic

<joshlieberman> It is certainly a part of work on geopackage

<stakagi> I have tiling slide

<stakagi> http://www.slideshare.net/totipalmate/tiling-51301496

<ChrisLittle> OGC WCTileService has three phases. first, now is for pixel tile, second then point clouds, then lastly geometries, whichare close to SVG

<stakagi> Tiling on SVG is (probably) much different from WebGIS's tiling architecture.

<kerry> stakagi, people are speaking about interest in this tiling topc

<Frans> Is http://www.w3.org/Submission/SVGTL/ likely to be included in SVG2?

<phila> How do you define a pixel, ChrisLittle? (CSS pixels are not equal to actiual pixels on the screen for e.g.)

<Linda> I share phila's question: Isn't the point of SVG for maps that we can do away with tiling?

<stakagi> Most differnt point is "non arithmetical-pregression".

<ChrisLittle> Currently, Joan and I are interested in establishing a n-dimensional tiling architecture, to supercede 2-D and layers

<ChrisLittle> this may not be of interst to 2-D SVG

<Frans> We could do away with image tiling, vector tiling is a different subject.

<joshlieberman> Certainly an SVG capability to work with multiple coordinate reference systems as Web mapping apps do, would be very useful (e.g. pixel, viewport, tiling scheme, projected CRS, geo CRS)

<ChrisLittle> +1 to that hierarchy

<phila> Do you have ideas for how the SVG work and this WG's work can be aligned, stakagi?

<stakagi> About our submission (http://www.w3.org/Submission/SVGTL/)

<joshlieberman> Darn, I was going to be impressed by the emphasis

<stakagi> we expressed that the submitted specification proposal should be once disassembled and it should have been reconstructed based on the view of the SVGWG members. It is because we thought that a generality increased by such procdess. Moreover, many of members of SVGWG are the developers of a well-known web browsers. And the specification which reached their consensus is easy to be implemented in a browser.

<joshlieberman> So do we need to consider SVG potential as a spatial data format or its compatibility with spatial data (as a graphic format)?

<Frans> I think SVG already is a spatial data format. Perhaps not geographic, but spatial yes.

<stakagi> Yes I think so.

joshlieberman: could we consider svg as spatial data format (with crs...)

<phila> joshlieberman: Is SVG a spatial format? That's one perspective. Another is, is SVG interoperable with other spatial data formats

joshlieberman: is svg interoperable with other spatial data formats

<kerry> stakagi, can you comment on interoperability with other spatail formats?

<ChrisLittle> SVG certainly made the processing chain in meteorology shorter

<Zakim> kerry, you wanted to ask about CRS

<stakagi> I think SVG is interoperable with other spatial formats

<stakagi> if CRS is resolved

<joshlieberman> Chris, is SVG used as a fully expressive spatial data format for mets, or a presentation format?

<kerry> Stakagi, how does SVG handle coord systems?

<ChrisLittle> I think various conversion tools like shapefile<->SVG or CGM existed

<stakagi> The specification of a geographic-coordinates system on SVG1.1 is described here.

<Frans> I think SVG will remain 2D? Most geographical formats are enabled for 3D

<ChrisLittle> SVG used for both presentation and archive, thoughI have concerns about latter in context of SVG2

<joshlieberman> Well, you can consider, e.g., Geoserver a conversion tool, but one of its output formats is SVG. It's a full rendering process, though, from shapefiles for example, requiring the addition of portrayal information.

<stakagi> Transformation for SVG is 3D.

<ChrisLittle> We used CGM for distribution of presentations and archive too, but CGM rather niche now

<stakagi> because CSS3 uses 3d transformations.

<ChrisLittle> CGM<->SVG very straightforward

<stakagi> and SVG is tightly coupled with CSS

kerry: so svg is 3d now?

<phila> Yep. I'm just looking for a ref to SVG 3 D

<stakagi> But geometry is still 2D.

<stakagi> http://www.w3.org/TR/SVG/coords.html#GeographicCoordinates

<Frans> Consider 3D source data to be transformed to SVG

<ChrisLittle> SVG2 has support for the 3D->2D pipeline, but is not strictly 3D

<stakagi> Yes.

<kerry> any comments onthe coords link anyone?

<stakagi> The specification of a geographic-coordinates system on SVG1.1 is described here. However, geographic-coordinates system on SVG does not agree of the policy described so far. The metadata which does not influence a rendition. Only for geospatial.

<Frans> support for spherical coordinates would be great

<stakagi> As expected, this specification is going to be obsoluted on SVG2.

<stakagi> Then, we proposed the concept of the global coordinate system for realizing the functionality of a tiling and layering. The global coordinate system could be used also as geographic coordinate system. Arbitrary global coordinate systems are specified as URI. However, the spec of SVG2 does not have a global coordinate system yet.

<ChrisLittle> I think SVG will not support spherical coords. you will have to look towards OpenGL

<Linda> It says " RDF description of the Coordinate Reference System definition used to generate the SVG map". Interesting....

<stakagi> https://www.w3.org/Graphics/SVG/WG/wiki/Proposals/Global_Coordinate_Systems

<stakagi> This is our proposal for "global" coordinate systems.

<ChrisLittle> Global coord system suggests links to OGC DGGS Digital Global Grid system work

<joshlieberman> Yes, that's an aspect of trying to make functionality that exists in OpenLayers or Leaflet a native browser function -- for example projecting WGS84 coordinates into Web Mercator for display overlay.

<ChrisLittle> -1 web mercator

<Frans> frans wonders how we can strengthen ties with SVG development in general and in the UCR doc specifically

<joshlieberman> ...As example of a projected coordinate system to avoid the "stupid" aka plat carre projection.

<kerry> satoru will be at tpac, although SVG WG is not meeting

<phila> Should we have a session about this at TPAC then?

<stakagi> Yes I will attend TPAC.

<ChrisLittle> +1 to session at Sapporo, though not going. Jeremy can cope.

<joshlieberman> I would suggest two lines of inquiry -- interoperability with spatial data, and a plugin mechanism for more capable spatiotemporal transformations.

<stakagi> SVG1.1's geographic coordinate systems specification is going to be obsoluted on SVG2.

<Frans> Perhaps we can at least mention SVG in the UCR document before TPAC

<Linda> The CRS reference topic is interesting for our CRS discussion as well.

<ChrisLittle> +1 to Josh's proposed activities at some stage

<stakagi> Because it is only for metadata. No influece for SVG rendering.

<kerry> josh: best practice we should look t svg and expressivness

<kerry> ... unclear how to express spatial data we need to learn this

<kerry> ... and maybe motivate some svg work

<kerry> ... sticking point is crs support

kerry: requires looking at transformations and crs support

<kerry> .... native mapping support is attractive but transformation and coords in a native implmentation is needed

kerry: is there a way to plug in transformation mechanisms that exist in JS (e.g. OpenLayers)

<kerry> ... can we suggest a way to plug in the transformation mechanisms we know of in javascript apps

<stakagi> What is transformation?

<ChrisLittle> +q

<kerry> ....so they do not need to be in every browser but can be plugins

<stakagi> latitude/longitude to X-Y?

<Frans> Satoro, do you mean CRS is not on the agenda for SVG 2?

<ChrisLittle> a plugin issue killed or seriiously damaged SVG ten years ago

phila: it would be interesting to define a JS-aligned web api to do a translation
... OpenLayers (or similar) could enact that

<stakagi> Probably we can't understand geo-community's CRS meanings.

phila: geolocations API (separate group) is defining an API for geofencing and so on

<stakagi> Yes I don't like plug-in or other extensions.

phila: just define the API, inner workings do not need to be detailed

<kerry> satoru, crs is an hot topic in the group, that we have not resolved

<Frans> I think there should be simpler level CRS definitions anyway

<Frans> ... we need to bridge the gap between geographical data and spatial data in SDWWG

<kerry> thank you satoru!

kerry: thanks satoru for making time

<joshlieberman> Thanks from Josh as well.

<kerry> ACTIONto kerry to follow up with SVG

<stakagi> The definition of CRS is unclear in general purpose

<scribe> ACTION: kerry to follow up with SVG [recorded in http://www.w3.org/2015/08/05-sdw-minutes.html#action01]

<trackbot> Created ACTION-60 - Follow up with svg [on Kerry Taylor - due 2015-08-12].

<kerry> Satoru, thank you for your presentation!

chrislittle: phila, which of the svg wg members with be in sapporo

<kerry> Satoru, I will ensure we continue a conversation, there is a lot of interest in this group

phila: doug will be there

<stakagi> Thanks.

<kerry> returning to webex

kerry: back to audio

<stakagi> I would like to understand CRS well first.

<Linda> Any hotel suggestions for Sapporo?

kerry: reminder: put your attendance on the wiki for TPAC

<ChrisLittle> I did!


<stakagi> The hotel in Japan is mostly narrow.

Best Practice Issues as raised by Jeremy

<Payam> Jeremy's email: http://lists.w3.org/Archives/Public/public-sdw-wg/2015Jul/0097.html

kerry: we ran a bit out of time
... i might coordinate with payam about trying to find volunteers

<Payam> https://www.w3.org/2015/spatial/wiki/BP_Consolidation

<Payam> https://www.w3.org/2015/spatial/wiki/BP_Consolidated_Narratives#Consolidated_narratives_.2F_common_themes

kerry: relating topics in the document with web architecture and use cases

<Payam> Jeremy's email: http://lists.w3.org/Archives/Public/public-sdw-wg/2015Jul/0097.html

kerry: thank you everybody, esp. to Satoru

<AndreaPerego> Thanks and bye

<Alejandro_Llaves> thanks, bye"

<billrobe_> thanks bye

<Linda> bye

<Frans> Goodday!

<BartvanLeeuwen> thx bye

<joshlieberman> Thanks bye

<kostas> thanks bye!

<ChrisLittle> bye and thanks

Summary of Action Items

[NEW] ACTION: kerry to follow up with SVG [recorded in http://www.w3.org/2015/08/05-sdw-minutes.html#action01]
[End of minutes]