WEBVTT

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We're going to go next speaker.

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Okay, hello everyone.

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Does that work?

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Yeah.

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No?

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No.

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The light is either fine.

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It doesn't work.

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Okay.

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Okay.

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So I have to speak out.

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Okay.

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So I'm really happy to be here.

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It's my first time at Phos Dam.

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So I'm going to be nervous.

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That's going to be fine.

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I'm going to talk to you about Open Layers, which has been mentioned about it as a talk.

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So that's great.

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So a little bit of introduction about myself.

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My name is Olivia.

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I work at a company called Camster Camp.

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A few words about Camster Camp.

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So it's a service company.

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It does geospatial as well as other stuff.

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It's for structure and hosting.

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It's based in Switzerland, France and Germany.

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And we're about 200 people.

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It's a great company that does a lot of open source.

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And you know, they allow me to be here.

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So it's great.

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And I have been working on the opening of this project for three years now.

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I contributed to some stuff.

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I touched a bit of everything.

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But mostly the WebJair Ranger stuff.

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Which we're going to talk about later.

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And you can reach me out and get our blue sky and it's my email address.

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So, right.

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Just a quick question first.

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Who here has used open layers before?

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Okay.

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It's quite a lot of great.

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So, okay.

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I'm really happy that the others will be able to discover it.

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So, open layers.

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It's a JavaScript library for doing interactive maps on the web.

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There's other open source libraries around.

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It's the main open source libraries are leaflets.

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Map library and open layers.

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But the open layers have been around for a long time.

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The first version was out in 2006 actually I checked.

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It was rewritten from scratch in 2013.

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And it's constantly evolving and improving.

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And I think that's pretty important.

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The codebase is very healthy.

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It's kept up to date.

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It's very well tested.

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Also, which is important.

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You can use it by doing npm install oil.

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So, it's an npm package.

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I come back to that a bit later.

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Quick screenshot of the GitHub repository.

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So, the website, the code source is hosted on GitHub.

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Open layers.

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And you can see here.

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So, it's been done for a while.

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So, we have a lot of stars.

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It's a bit of a vanity metric.

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A lot of commits.

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The license is BSD2 clause.

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We have almost 90 open per request.

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So, this number is increasing.

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The last time I do talk was half of that.

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So, the committee is active.

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But there's more.

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I guess it's a growing interest in it.

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So, it's good.

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But it's also hard to catch up.

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So, open layers has the reputation to be quite big library.

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Probably people have called it bloated at times.

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The important part, the important thing to understand is that

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open layers every feature is split into separate modules.

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So, you know, there's just one package, which is,

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I think a package, which is well.

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But if you only import the features that you need,

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it won't have too much of a burden on your code.

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That's really important.

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I mean, there should be tree shaking happening.

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So, if you don't use all of it, it cannot actually be quite light.

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And the reason for this is that contrary to leaflet, for example,

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open layers does not expect you to rely too much on a plugging ecosystem.

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There are extensions and plugins out there, and some of them are really good.

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But the library is thought to have all the main features inside

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and maintained in the core code at the same level of quality.

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Let's look at some stuff that we can do with the library.

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I want to cover a few topics. I won't have too much time to dive too deep.

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So, I'll just cover a few stuff, and then you can look for yourself afterwards.

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Vector data, oh, that looks, that works.

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So, you can see here, this is an example of basic vector layer example.

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This is a big geogation data set of the world.

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And I can pan around zoom in zoom out, works great.

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This example, I actually used the WebGA renderer.

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The way we define styles in open layers.

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So, I want to talk about this.

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If you use the paneers, maybe a few years ago,

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you might have used the mainstream styling API, which where you instantiate,

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style objects, and it's very valuable, it's quite complicated.

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I also utilize a lot on style functions.

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We introduced a couple of years ago, I think,

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the concept of expression based styling.

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So, instead of defining its complex styling objects,

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and functions that are evaluated all the time,

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you can just give it a set of rules of styling rules.

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And I hope this is readable, maybe not that much.

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So, each rule has a filter and style properties.

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So, the filter lets you select which objects will be affected by that rule,

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and then the style properties will be for these objects.

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This is very important move, and we really recommend people to use that.

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And a very important part of this is that filters and style properties

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can be, so here it's just a color, but you can also have expressions,

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so expressions for filters and for style properties.

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And this way, you don't have to rely on style functions anymore.

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You can define the style using these expressions.

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It's a quite, it's very powerful system.

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It's not very easy to use at first.

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We actually got most of the inspiration for the map library,

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style specification, which also use these concept expressions.

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If you use this kind of styling, you will be able to have better performance.

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For instance, if you want to use WebJair rendering,

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you have to use this, you can choose style functions.

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This is another example of vector data using WebJair,

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and you can see here, we apply a filter that actually changes along the line,

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according to values along the line.

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So, we can change the filter dynamically,

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and then have the lines render differently.

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We also have colors changing along the line.

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I think it's a very interesting example of what we can do with this style expressions.

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Which we couldn't do before.

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Vector data, you can also render it using clusters.

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It's pretty standard.

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You have also a heat map.

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And then, let's move on to type data.

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So, opinions, loves, type data.

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Obviously, it's very efficient for rendering.

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It comes in many different types and shapes.

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The most simple type data is image types.

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So, you can see here, you have a map types,

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come from IGN in France.

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So, opinions will just load the ties at the correct zoom level

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and stitch them together, and that's all working well.

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Here, you have an example that shows vector ties.

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So, same principle.

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Here, the vector ties, instead of being images

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are, you know, bunches of geometry isn't them.

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And here, they're not tied.

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So, you can see kind of what's looking,

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how it looks inside a vector tie.

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But most of the time, you would want to tie them, obviously.

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Oppenirers has a lot of logic for loading ties.

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You know, the right ties are the right time.

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You can see here, there's an animation, and I'm moving,

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animating the view from Burnt Brussels.

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And why the view is animating, you know,

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the ties that are shown change along the way,

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and Oppenirers try to find the best tie for the best zoom level.

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So, that the map stays crisp and readable.

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There's a tie queue system.

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You can change the size of the tie cage.

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This is all very elaborate.

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Tie data is distributed across tigrades,

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and I'll just want to mention this,

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because oftentimes we see ties on the web-necitol

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tigrade, right, the world is square,

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and we're split it by two and two.

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But a tigrade can be anything.

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It can be in different projections.

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It can be just over a certain area.

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And Oppenirers has no assumption of a tigrade

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that you use.

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Oppenirers also will handle devices with

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higher pixel density.

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So typically mobile devices,

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how it can have like two, three, four, and more dpi.

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And then the library will try and load the right ties,

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you know, use the higher quality ties,

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it's available and it's kind of things.

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Again, so that it stays very crisp on your screen.

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Vector ties also have decluttering apply to them.

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So typically if you have vector ties with the labels,

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you might not want to show all the labels at the same time,

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because they will be unreadable.

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So decluttering happens.

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And this is also a very elaborate system

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where you can change a lot of things.

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Rusted data.

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So Rusted data typically comes from satellite imagery,

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also like draw on other kind of photography.

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And what you can do in Oppenirers,

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you can actually, you can give the library raw Rusted data

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and render it in different ways.

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Here we use a geotif file,

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and then we compute on the fly the NDVI,

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so the normalized difference.

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Vegetation index.

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And to do that, we use again an expression.

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So here you can see we're creating a tie layer,

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which is for image ties.

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And this tie, instead of being for vector data,

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it just has a color property,

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and here we give it an expression.

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And this expression computes NDVI and DWI

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and assigns it to the different channels.

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This is all done.

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This is all done on the client, right?

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It's on the fly.

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And that means that you can just decide,

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you know, give the raw data to Oppenirers

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and decide how to render it.

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For example, here this data comes from Sentinel2.

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Here we're just assigning,

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you know, the visible color bands to the color channels,

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right?

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Red bands goes to random, et cetera.

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But we can also switch the styling

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and have the red channel be the infrared band,

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and the other channels be something else.

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And then, you know, you can, again,

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on the fly, you can just change the way

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the data is showing on a map.

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Oppenirers has a support for many different kinds of protections.

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This is also very important in the library.

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When you create a map by default,

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it's going to be web macator,

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like a sensible default.

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But you can give it really anything

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that's supported by Prash4.

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And here, for example, this is the map of the world

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using mall-vader projection.

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You can have many other kind of projections.

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You can have polar projections and these kind of things.

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And this is very important also.

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I want to emphasize in Oppenirers.

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You have the concept of the view projection, right?

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You decide what, how your map will be rendered

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with width projection.

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But you also have the projection of your data.

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So if your data comes from a different projection,

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an opening is mostly,

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most likely be able to convert it on the fly.

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If it's vector data,

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it will transform the core vector coordinates.

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And if it's raster data,

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it will also be able to distort the images

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so that it matches the projection.

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Right.

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Another addition that was done previously,

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that's recall, it's a flow layer.

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So it's a web-gear rendered layer.

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You can give it a grid of values,

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typically coming from a weather data.

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And then the layer will interpolate between those values

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and then make a field out of it,

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and then simulate particles going over it.

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It's a common visualization,

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but no, it's built in the library.

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You can have many different formats,

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and open layers.

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Just a quick list.

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Yeah.

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I'm just going to not spend too much time on this.

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Many different sources.

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Operators, no support,

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OGC API standards,

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so map and vector ties,

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classic OGC protocols,

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WMS, et cetera.

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Sentinel hub also is a source now,

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PMTIs.

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You can use Google Maps,

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if you have a key,

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state in Maps,

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Cloud Optimize Geotif is also a data source.

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The way it works is when you create a layer,

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you have to assign it to source,

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right?

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You have different kind of layers,

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different kind of source,

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and you kind of make that work together.

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I'm not going to have different control interactions.

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Again, I'm not going to spend too much time on this.

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Classic to draw interaction,

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select, modify,

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you can rotate the view,

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full screen, scale bar,

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the vertical,

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and this kind of things.

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This is an example of a draw interaction

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that uses tracing,

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which I think it's really nice.

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So you see here,

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you're going to draw a shape,

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and I think that would be cool,

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in terms of draw.

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And then you will have this kind of snapping

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way, it will follow a shape,

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and that's useful if you have complex shapes.

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This is also something that the draw interaction

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can do for you.

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Operators has first class mobile support,

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so I talked about pixel density,

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but also like when you create a map by default,

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it will work on mobile,

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so you can interact with the fingers,

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you can zoom in zoom out,

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you can rotate them up,

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and stuff things.

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It's really first class support.

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How to use the library?

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So, this is what it looks like,

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create a map.

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It's just a pretty simple example,

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and actually it will be much more complex than that.

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It's just the general concept you have a map,

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which contains layers, layers of sources,

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and then a map has a view,

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the view lets you center on objects,

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the view are very useful functions,

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if you want to center on an object,

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if you want to animate the view,

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compute an extent and this kind of things,

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and then you set up controls and interactions.

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The NPM package is called OEL,

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which is done before.

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It comes with type definitions,

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so open-airs is written in JavaScript,

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but it has JSDoc annotations,

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so it's a type library,

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and you get type flip support.

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If you use NPM instead of where we get the latest table version,

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you can use OEL adev,

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if you want to have the latest version on main,

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that can be really useful

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if the features that have not been released yet,

15:28.000 --> 15:31.000
the main version is usually very stable,

15:31.000 --> 15:34.000
that might be a few bugs that haven't been fixed yet,

15:34.000 --> 15:38.000
or breaking changes, but most of the time you get to go.

15:38.000 --> 15:43.000
There's a very extensive example list on the website,

15:43.000 --> 15:48.000
so open-airs.org eann latest examples.

15:48.000 --> 15:52.000
I usually suggest people to start with this.

15:52.000 --> 15:56.000
It's a very, yeah, it's like 258 examples.

15:56.000 --> 15:59.000
There's an example for almost every feature,

15:59.000 --> 16:01.000
if you're not sure if the library can do something,

16:01.000 --> 16:03.000
or what it looks like when it runs,

16:03.000 --> 16:05.000
then just take a look at the example

16:05.000 --> 16:07.000
and you should have your answers.

16:07.000 --> 16:11.000
There's an API doc as well.

16:11.000 --> 16:13.000
Recently, we came up with something interesting.

16:13.000 --> 16:16.000
We created a website for doing benchmarks,

16:16.000 --> 16:19.000
and that's because in the past year,

16:19.000 --> 16:24.000
and a half, we tried improving the performance of

16:24.000 --> 16:27.000
vector data rendering as much as possible.

16:27.000 --> 16:30.000
We invested a lot of time and energy in this,

16:30.000 --> 16:33.000
and together, an idea of how good the library was getting,

16:33.000 --> 16:35.000
we came up with these benchmarks.

16:35.000 --> 16:38.000
So these benchmarks have different cases,

16:38.000 --> 16:41.000
rendering polygons, rendering lines, etc.,

16:41.000 --> 16:44.000
rendering vector ties, and for each case,

16:44.000 --> 16:48.000
you have this shapes showing up,

16:48.000 --> 16:50.000
and you can change all the parameters,

16:50.000 --> 16:52.000
and increase the number of shapes,

16:52.000 --> 16:54.000
and see how far you can push the library,

16:54.000 --> 16:56.000
and basically by doing this,

16:56.000 --> 16:59.000
we try and find the soft limits of the library,

16:59.000 --> 17:01.000
and that's a very good indication

17:01.000 --> 17:06.000
of should we improve this part of the rendering further or not.

17:06.000 --> 17:08.000
You can switch from WebGL,

17:08.000 --> 17:12.000
you can switch on of WebGL rendering,

17:12.000 --> 17:15.000
and you can also, there's a performance tracker,

17:15.000 --> 17:19.000
which lets you give you an idea of what's going on at each frame,

17:19.000 --> 17:24.000
and this is very interesting for us,

17:24.000 --> 17:26.000
when you try to improve the performance,

17:26.000 --> 17:27.000
but I think it's also interesting,

17:27.000 --> 17:29.000
you can take a look at it,

17:29.000 --> 17:32.000
if you want to have an idea of how the library runs,

17:32.000 --> 17:34.000
and what performance you can expect from it.

17:34.000 --> 17:38.000
So the website is operative.org-bench,

17:38.000 --> 17:41.000
and you can also change it with different past versions,

17:41.000 --> 17:44.000
and see how it affects that's pretty cool.

17:45.000 --> 17:48.000
So we worked a lot on the performance of vector data,

17:48.000 --> 17:51.000
and that's mostly done through WebGL rendering,

17:51.000 --> 17:53.000
which I talked a little bit.

17:53.000 --> 17:56.000
Just a few words to say,

17:56.000 --> 17:59.000
why I think this project is important,

17:59.000 --> 18:02.000
and why I care about it very much.

18:02.000 --> 18:05.000
So I mentioned the other open source libraries,

18:05.000 --> 18:07.000
my library and leaflet.

18:07.000 --> 18:12.000
I think each library has their strong points and weaknesses.

18:12.000 --> 18:15.000
The thing is, it's not easy to use.

18:15.000 --> 18:17.000
It has a bit of complexity,

18:17.000 --> 18:20.000
but you can do really much anything.

18:20.000 --> 18:22.000
You can throw pretty much anything at it,

18:22.000 --> 18:24.000
and it will render it.

18:24.000 --> 18:27.000
It's completely agnostic to the source providers,

18:27.000 --> 18:30.000
data providers, the data,

18:30.000 --> 18:32.000
can be detailed data or not,

18:32.000 --> 18:34.000
many different formats and projects.

18:34.000 --> 18:37.000
The project is not owned by a company.

18:37.000 --> 18:39.000
It's a true community project,

18:40.000 --> 18:44.000
and I have to say it's a very neutral project,

18:44.000 --> 18:47.000
because there's no assumption about anything.

18:47.000 --> 18:50.000
I said Western assumptions,

18:50.000 --> 18:53.000
because you can use it in different projects,

18:53.000 --> 18:55.000
different parts of the world.

18:55.000 --> 18:57.000
We have regularly Chinese users,

18:57.000 --> 18:59.000
I think showing up at the GitHub,

18:59.000 --> 19:01.000
which makes communication hard,

19:01.000 --> 19:04.000
but I think that's a very interesting thing.

19:04.000 --> 19:08.000
Also, a good example is text rendering on the map,

19:08.000 --> 19:12.000
because we rely on the text rendering of the browser.

19:12.000 --> 19:14.000
It means that text can be anything.

19:14.000 --> 19:16.000
It doesn't have to be our alphabet.

19:16.000 --> 19:17.000
You can be right to left.

19:17.000 --> 19:18.000
You can be different characters,

19:18.000 --> 19:21.000
and these all works really well.

19:21.000 --> 19:24.000
So, yeah.

19:24.000 --> 19:27.000
Just a quick word to say that,

19:27.000 --> 19:28.000
if you want to help,

19:28.000 --> 19:30.000
you welcome to GitHub.

19:30.000 --> 19:31.000
You can try it out.

19:31.000 --> 19:33.000
If you find a bug, please report it.

19:33.000 --> 19:35.000
If you want to try your candidate,

19:35.000 --> 19:37.000
please try and open a pull request,

19:37.000 --> 19:40.000
and people will help you out, no worries.

19:40.000 --> 19:42.000
Yeah, that's it.

19:42.000 --> 19:43.000
Time for questions.

20:00.000 --> 20:01.000
Okay.

20:06.000 --> 20:10.000
So, you put requests when was it opened?

20:10.000 --> 20:12.000
Before what?

20:12.000 --> 20:14.000
Okay.

20:14.000 --> 20:15.000
Right.

20:15.000 --> 20:20.000
So, also, keep in mind that people sometimes use their own time to work on this.

20:20.000 --> 20:24.000
So, you know, basically what you try and do is say,

20:24.000 --> 20:27.000
yeah, okay.

20:27.000 --> 20:28.000
I'll have to look at it.

20:28.000 --> 20:30.000
I can say, yeah.

20:30.000 --> 20:31.000
It's very great.

20:36.000 --> 20:37.000
Yep.

20:37.000 --> 20:39.000
You're saying, like, obviously, open this,

20:39.000 --> 20:41.000
has a lot of function.

20:41.000 --> 20:46.000
Maybe, or, like, in reference to something like,

20:46.000 --> 20:47.000
if there's a lot of stuff,

20:47.000 --> 20:50.000
it should be in the same direction to open it.

20:50.000 --> 20:51.000
Right.

20:51.000 --> 20:53.000
How do you, like, the main thing is to size,

20:53.000 --> 20:57.000
like, what to, what should be included in the pull library,

20:57.000 --> 20:59.000
and what to, like, you know,

20:59.000 --> 21:04.000
potentially,

21:05.000 --> 21:07.000
how does that discussion happen?

21:07.000 --> 21:09.000
So, the question is,

21:09.000 --> 21:13.000
how do maintenance decide what gets put inside the library,

21:13.000 --> 21:17.000
or what maybe is left for other plugins to do?

21:17.000 --> 21:19.000
I think the library tries to have as many,

21:19.000 --> 21:22.000
200 as many providers and formats as possible.

21:22.000 --> 21:24.000
So, you know, if there's something coming up,

21:24.000 --> 21:26.000
and, for example, the OGCAPI standards,

21:26.000 --> 21:28.000
then, you know, they became more stable,

21:28.000 --> 21:30.000
and then there was supported in the library.

21:30.000 --> 21:32.000
When it comes to functionality,

21:32.000 --> 21:34.000
it's more like high level stuff,

21:34.000 --> 21:36.000
like interactions, or complex drawing,

21:36.000 --> 21:37.000
things, for example.

21:37.000 --> 21:38.000
Then, usually it will be like,

21:38.000 --> 21:40.000
maybe, you know, people can do that,

21:40.000 --> 21:44.000
you know, extensions, or in their application code.

21:44.000 --> 21:47.000
The interaction stuff stays quite low level, I would say.

21:52.000 --> 21:53.000
Yes?

21:53.000 --> 21:55.000
So, how is the interaction done?

21:55.000 --> 21:58.000
Is it only, like, going with the,

21:58.000 --> 22:01.000
what is the interaction done?

22:01.000 --> 22:06.000
Okay, the question is about drawing,

22:06.000 --> 22:08.000
the drawing interaction, how can you,

22:08.000 --> 22:11.000
so the default drawing interaction,

22:11.000 --> 22:13.000
again, you can click,

22:13.000 --> 22:15.000
set a vertex at every click.

22:15.000 --> 22:17.000
You also have a free-and-mode,

22:17.000 --> 22:20.000
but you can also programmatically push coordinates.

22:20.000 --> 22:22.000
And that's what we do in the tracing stuff, right?

22:22.000 --> 22:24.000
When you snap to a polygon,

22:24.000 --> 22:27.000
then we push coordinates without clicking.

22:27.000 --> 22:29.000
Yeah, but we think, if I have a format,

22:29.000 --> 22:33.000
then I just want to eat it here.

22:33.000 --> 22:37.000
If I want to trap objects on a map.

22:37.000 --> 22:38.000
Right?

22:38.000 --> 22:44.000
If you want to feel your map with data,

22:44.000 --> 22:46.000
you don't need to do, like,

22:46.000 --> 22:48.000
interaction is really when it comes to,

22:48.000 --> 22:49.000
like, the user doing something,

22:49.000 --> 22:52.000
but if you programmatically want to push objects in your map,

22:52.000 --> 22:54.000
then you don't need interactions.

22:54.000 --> 22:56.000
You basically push data on your source,

22:56.000 --> 22:59.000
at the source level, and then it shows up on the map.

22:59.000 --> 23:01.000
Yeah?

23:01.000 --> 23:02.000
Yeah?

23:02.000 --> 23:04.000
Can you share the words,

23:04.000 --> 23:07.000
how do you do performance testing on mobile devices

23:07.000 --> 23:09.000
in their, like, constraints in the CPU,

23:09.000 --> 23:12.000
or RAM, or in cases of, like,

23:12.000 --> 23:14.000
that network, or, you know,

23:14.000 --> 23:16.000
with your mobile device, or,

23:16.000 --> 23:21.000
okay, so about performance on mobile.

23:21.000 --> 23:24.000
So network, you can do a flying stuff with open layers,

23:24.000 --> 23:26.000
but it's not really handled by the library.

23:26.000 --> 23:30.000
You know, if you push the data into a source,

23:30.000 --> 23:32.000
if you're offline, or online,

23:32.000 --> 23:34.000
actually the library doesn't really care.

23:34.000 --> 23:39.000
The library tries to be as light as possible on, on battery.

23:39.000 --> 23:41.000
This benchmark website is also,

23:41.000 --> 23:44.000
it can also be used to test stuff on mobile.

23:44.000 --> 23:47.000
So, yeah, basically, yeah.

23:47.000 --> 23:49.000
But, I mean, for a long time,

23:49.000 --> 23:51.000
we just, we didn't have any proper metrics, right?

23:51.000 --> 23:53.000
We were just trying stuff, you know,

23:53.000 --> 23:55.000
like, try the examples on your mobile,

23:55.000 --> 23:58.000
or use an emulator or something.

23:58.000 --> 24:02.000
But, no, we tried to have better metrics.

24:02.000 --> 24:03.000
Yeah.

24:08.000 --> 24:10.000
Okay.

24:11.000 --> 24:12.000
Thank you.

24:12.000 --> 24:15.000
Thank you.