[Talk-GB] Idea - OSMUK walkers' map application -- -& server

Nick Whitelegg nick.whitelegg at solent.ac.uk
Mon Dec 14 12:22:19 UTC 2020


Hello Adam,

OK - that's great, thanks!

Does the AWS hosting include full shell access? We'll need that to install the relevant software.

Let me know if/when the server space is available.

In the meantime I will create a Hetzner server to start experimenting, this will be around EUR4/month which I am prepared to meet in the short term, I will also give accounts to trusted members of the community on request to work on the project should they wish.

Nick




________________________________
From: OSMUK <adam at osmuk.org>
Sent: 13 December 2020 18:36
To: talk-gb at openstreetmap.org <talk-gb at openstreetmap.org>
Cc: Nick Whitelegg <nick.whitelegg at solent.ac.uk>
Subject: Re: [Talk-GB] Idea - OSMUK walkers' map application -- -& server

Hey Nick,

This sounds like a great project and so I’m sure OSMUK can help with server space. We have just migrated hosting to AWS due to our previous host shutting down, so one option is to provide some space on there.

Best,

Adam

--
Adam Hoyle
[m] 07973 428 333
On 11 Dec 2020, 15:02 +0000, Nick Whitelegg via Talk-GB , wrote:

Hello Andy,

Thanks for this.

My own feeling regarding what server we need is "start small, to get it going" and then as soon as OSMUK can commit to funding (*if* they can, of course) and/or several people share the cost, then scale up. Hetzner's model is very flexible in this regard, for instance I started with an 8GB RAM VM before I found it wasn't quite adequate for my needs and upgraded the same VM to the 16GB version (and added some disc space, I think, too). For now I am willing to spend a small amount (below EUR/GBP 5) for a month or two to get things going if there's sufficient interest.

I'd broadly agree to an extent about going the Mapnik route although I would prefer another person with more experience in the niceties of current Mapnik stylesheet development to do large-scale tweaks;  I would be happy to do small​ tweaks on such things as, for example, making designations appear in a similar style to Landranger which might be an idea for familiarity purposes. On the other hand, vector rendering would have some advantages for the aims of this project - an interactive map of the countryside in which POIs and paths can be clicked to add/retrieve information. I believe Tangram can do this quite easily; I have dabbled in Tangram and it's quite easy to setup a simple stylesheet though haven't tried it with anything complex. Tangram also has some nice things like being able to be rendered in both isometric and (via A-Frame components, https://aframe.io) even in 3D. I have to admit having a personal like for the vector approach,   it shifts more processing onto the client, good in a world where standard client hardware, desktop and mobile, is pretty powerful while powerful server hardware is expensive.

I wouldn't personally be so fussed about things like minutely updates until it becomes a 'production' map, while in development mode I think the best approach is to keep it simple and cheap to run. In terms of my own projects I do quite rigorous filtering of the OSM data before populating the DB, to reject things mostly of interest to urban areas which only use up space and resources in a walking-oriented map. Another way of keeping initial costs down would be to concentrate on one or a few counties, ideally well-mapped ones with many ROWs, hills, water features etc.

So I'd be quite happy - if​ there's interest - to setup a cheaper Hetzner server for now. If we want to go the mapnik route I'd be happy to do a basic setup there as well, as in, get mod_tile working and use your style unmodified. My main personal contribution to the project would be to work on the server- and client-side scripting necessary to develop an interactive POI map. We'd also of course need people with strong web design and UX skills - alas, mine are not so great!

As for other points - things like https cert renewal seem easy with Let's Encrypt; have been using that succesfully for a while now.

Nick



Nick Whitelegg
Senior Lecturer in Computing (Internet)  | School of Media Arts and Technology
Southampton Solent University  | RM424 | East Park Terrace | Southampton SO14 0YN
T: 023 8201 3075 | E: nick.whitelegg at solent.ac.uk<mailto:nick.whitelegg at solent.ac.uk> | W: solent.ac.uk<http://www.solent.ac.uk/>

Disclaimer<http://www.solent.ac.uk/disclaimer/disclaimer.aspx>
________________________________
From: Andy Townsend <ajt1047 at gmail.com>
Sent: 11 December 2020 13:40
To: talk-gb at openstreetmap.org <talk-gb at openstreetmap.org>
Subject: Re: [Talk-GB] Idea - OSMUK walkers' map application -- -& server



On 11/12/2020 09:59, Nick Whitelegg via Talk-GB wrote:

In the early stages I think we could run it on cheap hosting hardware, like most projects in the OSM ecosystem. I suspect for a while usage would be light and limited to those in the OSM community. I use Hetzner for my hosting (OpenTrailView, Hikar, MapThePaths) - I pay around EUR 19/month but that is for a larger system that has to deal with the whole of Europe rather than just the UK.

 https://www.hetzner.com/cloud?country=gb

The second-lowest spec of these, the CPX11 is giving you 2GB RAM and 40GB disc space for EUR 4.19 a month. OK we'd need more than that long term, but I suspect that would get us going in the early stages.


That'll depending on what you want the server to do, I think.  For an OSM Carto Map style with automatic updates and reasonable performance you'll probably need > 6Gb memory for the whole of the UK these days.  Maybe a CX31 at €11 per month (i.e. about the price of a couple of pints and a "substantial" pork pie for those in tier 2)?  https://map.atownsend.org.uk is a CX41 I believe, and renders Mapnik / Carto CSS map tiles that cover UK and Ireland.  It could probably include another "medium sized OSM country" in the same map style as well without too many problems.


On the question of "could we show feature X" (e.g. "cycleways with foot=yes" different to "cycleways with foot=no) the answer is technically yes, but you need to decide which subset of features you want to show because there simply aren't enough ways of visually distinguishing things that users can actually tell apart, especially when combined with other features.


As an example, have a look at the legend at https://map.atownsend.org.uk/maps/map/map.html#zoom=16&lat=-24.98988&lon=135.10862 .  That shows:

  *   designation (public footpath / bridleway / retricted byway / BOAT / UCR / none)
  *   width - either "narrow" (not wide enough for a 4 wheeled vehicle) or "wide" (wide enough)
  *   trail_visibility
  *   some surface information (unclassified unpaved roads rendered differently to paved roads)
  *   tunnel yes/no
  *   long ford yes/no
  *   bridge yes/no
  *   embankment yes/no
  *   long distance foot / bicycle / horse riding routes
  *   access=destination and =private viewed from a pedestrian perspective

and of course combinations of the above.


It does not show:

  *   explicit OSM keys (e.g. footway/cycleway/path/bridleway)
  *   explicit OSM access tags (e.g. "foot=yes or no on a cycleway")
  *   undesignated cycleways differently from other undesignated paths

In order to one of those (for example just "displaying cycleways as cycleways") you'd need to remove something else that's already rendered, otherwise users won't be able to tell features apart.


Assuming that people are planning to go down the mod_tile / Mapnik / Carto CSS route, I'd suggest:

  1.  decide what zoom levels you want, which will influence exactly which software to use
  2.  deciding where to start from (e.g OSM's Standard style, mine, or a different one altogether)
  3.  deciding exactly what you want to change
  4.  make those changes,
  5.  see what "unintended consequences" have occurred
  6.  fix those and iterate round until happy

Assuming you can deal a couple of hours overnight downtime while the database reloads I'd suggest doing most of the "deciding what to show as different things" work in lua and the "deciding what to show it as" in Carto CSS.  It's much easier to understand and to maintain.


With regard to the "boring bit" (scripts to load databases, keep databases up to date etc.) most of the stuff used by https://map.atownsend.org.uk is public (links to everything are at the top of the changelog).  Much of the rest (e.g. automatic https certificate renewal) is standard and is documented in 1000s of other places around the internet.  If anyone wants any help or advice with any of the above please just ask.


There may be a temptation to think "the end goal is a phone app , so actually we probably want to look at $some_other_technology instead".  I would strongly suggest following a well-trodden path first while so that the things that are new to whoever is doing this are have well-documented solutions.  I haven't yet found a vector tile stack that is (a) well documented and (b) free of vendor lock-in that could go on https://switch2osm.org/serving-tiles/ yet, for example.  Once whoever is doing this is familiar with things, trying something a bit more off-the-wall will be more likely to work without everything breaking.


The biggest requirement is for someone to actually commit to doing the work to set something up - nothing will happen without this.  If OSM UK are happy to fund a server, and for it to fit in their DNS somewhere then that's one less expense to worry about - but someone still needs to do the work.


Best Regards,


Andy




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