Update colours / symbology of Truck Routes layer (mentioned in #204)

[NicoledeGreef]

To be discussed at meeting on March 9, 2022. The main part of #204 has reached Production already.

[NicoledeGreef]

Current symbology concerns discussed.
Truck Routes is most important layer; then Major Road Network. Symbology adjustment and draw order change may be in order. Currently SMK draw layers according to the order they are configured in the app (would be about a week's worth of effort to adjust this); more likely the order of the layers in the app will be adjusted in order to change the draw order.
Line thickness & colour most likely to change; adjustments at various zoom levels possible.
@gk-tl and @al-tabb to send specifics for change request.

[al-tabb]

@gk-tl and I have come up with a couple of options for revised symbology. It would be great to get your feedback on which one your prefer.
The 'draw order hierarchy' will be the same regardless of the colour differences between the two options (from bottom (1) to top (4)). The number after each layer denotes a thickness value (1 being the thickest and 5 being the thinnest)

Draw Order - Thickness Value

1. Truck Routes - Thickness of 1
2. MRN - Thickness of 2
3. Term Permit Routes - Thickness of 2
4. OS-OW Routes (in the following order):
   Overall Height up to 4.33m - Thickness of 3
   Overall Width up to 5.00m - Thickness of 4
   Gross Vehicle Weight up to 80,000 kg - Thickness of 5
   Gross Vehicle Weight up to 85,000 kg - Thickness of 5
   Gross Vehicle Weight up to 100,000 kg - Thickness of 5

I believe that moving the MRN to this position in the draw order will also move it in the layer list. This is fine.

Thickness and relationship to zooming
The lines should all be approximately the same thickness when zoomed out at a regional level. The further we zoom in the lines should gradually change their thickness to accommodate the hierarchy established above. At the highest zoom level the difference between the thickness levels should be the most drastic and we should be able to distinguish the overlap between all 5 thicknesses. Hopefully this will provide a happy medium between being able to discern the overlap of the layers while also not cluttering up the map at lower zoom levels.

Option 1 Symbols
Truck Routes:

MRN

Term Permit Routes:

OSOW Routes (order not correct, see above for order):

Option 2 Symbols
Truck Routes:

MRN

Term Permit Routes:

OSOW Routes (order not correct, see above for order):

[dgboss]

@al-tabb I'm looking into these symbolization changes, but I'm bumping into a CORS issue when when trying to run the app in my dev environment. Would it be possible to add 'translink-d.apps.gov.bc.ca:7443' as an allowed origin for https://devapi.regionalroads.com?
Thank you!

[al-tabb]

Sure, I've added the requested URL to the allowed origins list. Let me know if you have any more issues.

[dgboss]

@qqnluaq in my experience I've found the symbolization options in Leaflet to be somewhat limited. I'm not aware of a clean, out of the box solution for generating the Truck Route symbols in the images above. I know you can stack multiple layers to get those kinds of line symbols, but I don't know if we could generate those symbols in the legend or layer list. Are you aware of a way to support this symbology on the map and legend?

[qqnluaq]

@dgboss Yes, generating this styling for the layers is possible by stacking copies of the layer rendered with different styles.
Generating the appropriate legend automatically in SMK would be possible too, but it might not be worth the effort to fix the legend rendering code. An easier solution would be to use a static image for the legend

[al-tabb]

We're OK with using a static legend if it makes this change easier to implement.

[NicoledeGreef]

That's great to hear @al-tabb because it seems that's where we've landed due to the complexity of the proposed changes. We are anticipating hearing more about availability for starting this work. In terms of feedback, consensus here is that option 2 in the attached file looks more polished.
option_comparison.pdf

[al-tabb]

Due to the colour scheme of the new basemap we're thinking that option 1 is preferred so that the layers will stand out. In response to the comment in the pdf we are open to changing the line thicknesses closer to option 2 to get a cleaner look. The symbology provided (especially the exact thickness of lines) can be adjusted a bit to fit the aesthetic of the map as needed. Let me know if this works on your end.

[qqnluaq]

@al-tabb A few questions:
The new layer style guide includes 'port restricted access', which doesn't exist on the map at present.
Also it mentions 'truck travel restriction or prohibition', but the closest the existing map gets to that is:

You also mention that the line thickness should increase as you zoom into the map. Right now there is one step in the line styling at a scale of 1:19000.
I think the new style guide reflects the style when the map is zoomed in beyond that scale, but the guide doesn't have much to say about the style when zoomed out,

[al-tabb]

You're right that isn't consistent with the current map.

All features with an 'AdvisoryType' = "Restriction" should have the symbology specified for "Truck Travel Restriction or Prohibition". Let's continue to represent this as 'Restrictions' similar to the current legend (i.e. Truck Travel Restriction or Prohibition and Port Restricted Access will collapse into one category).

All features with an 'AdvisoryType' = "Truck Travel Warning" should have the symbology specified for "Truck Travel Warning". Let's continue to represent this as 'Advisories' similar to the current legend (i.e. Truck Travel Warning will be relabeled to Advisories.

As for the thicknesses I think there will be some trial and error there. I don't have exact widths based on zoom levels in mind.
I'm looking for something that hopefully provides a happy medium between being able to discern the overlap of the layers while zoomed in (i.e. lines are visually at their thickest and difference between line thicknesses is most extreme) while also not cluttering up the map when zoomed out at the regional level (lines are visually at their thinnest while differences between line thicknesses is almost non-existent).

[qqnluaq]

@al-tabb Another question:
Right now the provincial highway is represented on the map in 2 different ways, under the Truck Routes, and then again as its own layer entry.
Is the new style for the provincial highway being applied to both uses?

[gk-tl]

@al-tabb Another question: Right now the provincial highway is represented on the map in 2 different ways, under the Truck Routes, and then again as its own layer entry. Is the new style for the provincial highway being applied to both uses?

Hi Ben - as its own layer, Provincial Highways can stay as is. The layer is meant to be used in conjunction with the MRN layer when a user is primarily interested in showing the extent of the MRN (i.e., all truck route layers are turned off, as shown in the image)

[gk-tl]

Related to the above, it would be helpful if the symbology for the truck route layers (collectively the TRN) could be set up such that when the MRN layer is selected, it is easy to see the overlap between the two networks (for example, see which segments of the TRN are not part of the MRN and vice versa).

[qqnluaq]

@gk-tl @NicoledeGreef A new build with my styling changes in dev: https://translink-d.apps.gov.bc.ca/trp/

[al-tabb]

@qqnluaq Thanks for putting this together. A few comments/questions:

• The Provincial Highways layer should be a thick black line with a white dotted line.
  
• The MRN layer seems to disappear when zooming in past a certain point
• Is it possible to have the legend show straight lines as opposed to curved lines?
• Is it possible to space the dashes in the dashed lines further apart? I think this may reduce the "clumping" I see at certain zoom levels.
• Is it possible to implement the different line thicknesses as specified or is this proving difficult to implement? The idea is to hopefully be able to distinguish the overlap between layers by using different thicknesses that become more drastic at increased zoom levels.

[qqnluaq]

• the provincial highways appears in the layer list in 2 places, under truck routes (with styling as described), and again with the blue line. This point was addressed already: Update colours / symbology of Truck Routes layer (mentioned in #204) #221 (comment)
• the MRN layer visibility is fixed, and the position of the layer moved to be directly under truck routes
• the legend for line features has been changed
• the styles that use a dotted line have been updated so that the gaps are larger
• the line thickness have been adjusted to conform to spec

These changes are deployed to dev, please verify
cc: @NicoledeGreef @al-tabb @gk-tl

[NicoledeGreef]

Thanks @qqnluaq

@al-tabb here is the Dev URL for your review:
https://translink-d.apps.gov.bc.ca/trp/

[al-tabb]

@qqnluaq

• The provincial highways layer still has symbology matching the Municipal Roads with No Truck Travel Restrictions. It should be a thick black line with a thinner dotted white line on top.
  
• The draw order is as follows (the MRN should be on top of the TRN):
  • Draw Order (1 = bottom, 4 = top) - Thickness Value (1 = thickest, 5 = thinnest)
    • Truck Routes - Thickness of 1
    • MRN - Thickness of 2
    • Term Permit Routes - Thickness of 2
    • OS-OW Routes (in the following order):
    • Overall Height up to 4.33m - Thickness of 3
    • Overall Width up to 5.00m - Thickness of 4
    • Gross Vehicle Weight up to 80,000 kg - Thickness of 5
    • Gross Vehicle Weight up to 85,000 kg - Thickness of 5
    • Gross Vehicle Weight up to 100,000 kg - Thickness of 5

-Can the thicknesses be made to match the specs above? Can the difference between the thickness levels be made more drastic (i.e. start with the truck routes thicker and go gradually thinner at each level from there)? The hope is that we'll be able to find thicknesses for each layer that will allow us to distinguish the overlap between them especially when the map is zoomed in.

[qqnluaq]

@al-tabb made updates per your last comment, deployed to dev.
cc @NicoledeGreef @gk-tl

[NicoledeGreef]

Changes for review in: https://translink-d.apps.gov.bc.ca/trp/