Support for line weight in `addGlpolylines`

[chintanp]

Leaflet addPolylines has a weight feature, and would be good to have here as well. Maybe depends on the upstream repo. Just mentioning for completeness.

[tim-salabim]

Yes, it isn't available in the upstream dependency. I am assuming you'd want to map weight to a variable?

@robertleeplummerjr any estimation on how much work it would be to include something like this?

[chintanp]

Yes, preferably a list or a scalar. List length equal to the length of the polyline, so each polyline can have a different weight. My leaflet app shows this: cp84.shinyapps.io/wsdot_evse2

The main problem there is speed. I tested the leafgl map to load much much faster, but variable line-weight is crucial for my application.

[tim-salabim]

@chintanp I get a "404 Not found" at the link you provided above... Can you share a working link?

[chintanp]

@tim-salabim : I am sorry, the correct URL is: https://cp84.shinyapps.io/WSDOT_EVSE/ . The code is here: https://github.com/chintanp/we_inf_display/blob/master/app.R

[tim-salabim]

Thanks! Nice map. It seems responsive enough though. So you're mainly concerned about loading times?

[chintanp]

yes, I have one more layer to add, it includes a buffer around the roads and with it, the overall loading time is close to 20 seconds. Just wondering if I can slash that somehow.

…

On Mon, Aug 12, 2019 at 1:09 AM tim-salabim ***@***.***> wrote: Thanks! Nice map. It seems responsive enough though. So you're mainly concerned about loading times? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#22?email_source=notifications&email_token=AAFXZZPHZHYBY6LSCKJDVFLQEELCVA5CNFSM4IJ5BI5KYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD4B2N7A#issuecomment-520333052>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAFXZZLDOXHM4R7O6YAKU43QEELCVANCNFSM4IJ5BI5A> .

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[tim-salabim]

You could add the buffer layer using leafgl I guess (if it's polygons).

[tim-salabim]

Closing here. Feel free to reopen if necessary

[robertleeplummerjr]

I'm trying to get some time to add this. I added this POC locally this morning that is webgl capable: http://somup.com/cql0bwfCjh

It is super lo-fi, but it prooves my theory. The technique used here is re-drawing the same line layer, but offset it and draw it a few times. This causes the lines to act as a brush, which I scroll in a bit too far to show its really 1 line drawn 10 * 10 times (-5 offset to positive 5 offset for both the x and y axis).

[robertleeplummerjr]

Ok https://github.com/robertleeplummerjr/Leaflet.glify/tree/36-line-thickness has a working solution, with documentation. It is experimental, but should give us most of what is needed here fyi. @tim-salabim, care to give it a try with this project?

[tim-salabim]

@robertleeplummerjr thanks for tackling this. I will test over the christmas holidays.

[robertleeplummerjr]

A gentleman and cartographer.

[tim-salabim]

@robertleeplummerjr it works indeed! This is what I see for thickness: 10 at zoom 20

Though, in order to address the OP's original issue, we would need to be able to optionally pass a vector/array of thicknesses for each line, so that line thickness can vary and thus be mapped to another variable (more spatial data science visualisation than cartography - this is R statistics after all). Is this possible? E.g. similar to how colors are being mapped to geometries?