[OHM] A question regarding coast lines

Mon Sep 9 16:32:08 UTC 2019

Jeff,

Thank you very much for your answers. Your observations have already been
very helpful and are helping me insert some collaborations on the platform.

Like I said, my first goal is to map railways and tram lines in Rio de
Janeiro. A first look at the work can already be seen (
https://www.openhistoricalmap.org/#map=12/-22.9344/-43.2075&layers=H).
Physical geography is both a challenge and a necessity: Like Seattle, Rio
has also undergone numerous transformations on its coast and water bodies.
I have made some edits in this regard, but I intend to leave the heaviest
part of the work to a second phase.

Historical maps of Rio de Janeiro produced by the Army Geographic Service
have been my primary source. I have used this one (
http://objdigital.bn.br/objdigital2/acervo_digital/div_cartografia/cart537339/cart537339.html?fbclid=IwAR1osTfR5JBo5xghn6aDV023aTR1398ZyBQUvzMxNFzRrRzmRcywpQcZq0Y
) often.

I will send more updates as the work progresses.

My most friendly greetings! :)

Em qui, 5 de set de 2019 às 14:00, Jeff Meyer <jeff at gwhat.org> escreveu:

> Guilherme -
>
> Fantastic! So glad you are finding it useful. Please share the links to
> what you're working on - I think plenty of people would love to check it
> out!!
>
> So, you're hitting on some tough topics & I'll do my best to answer,
>
> 1. Shorelines. Shorelines, as in the boundary between continents and
> oceans / major bodies of water can be tricky for now. OSM actually handles
> these a bit differently from other objects / relations. You can see more
> about that here: https://wiki.openstreetmap.org/wiki/Coastline It's
> something we will be working on in the future, as how coastlines change
> over time is super interesting & important, as you point out. But, the good
> news is...
>
> 1.a. You can temporarily (sorry!) work (hack?) around changes in
> shorelines until we get that fixed / working (hopefully in the next couple
> months) by putting a lake in the middle of your ocean. Any non-coastline
> body of water is treated just like anything else with start_date and
> end_date tags. You can see an example of this in a mockup of early Seattle
> I'm working on here:
> http://openhistoricalmap-1936150974.us-east-1.elb.amazonaws.com/#map=17/47.59962/-122.33220&layers=O
>
> 2. For two time frames for the same object - e.g. where attributes for
> that object are changing over time, that's also an issue at the heart of
> this project: how do you track changes to an entity over time - e.g. name,
> parent/territory (e.g. of a country / city), paving of roads,
> electrification of train lines, etc. There are issues with almost every
> proposed solution for data structure, but I think we'd want some sort of
> upstream object that ties downstream objects (e.g. our OSM data types)
> together, etc., but we aren't there yet. And, as always, we're looking for
> solutions. In the mean time, my only suggestion for workaround is to
> duplicate the objects in place, put an end date to the non-electrified
> lines, and then add a start date and electrical tags for the electrified
> lines. I've done that with the roads/streets in Seattle.
>
> 2.b. I think that's close to the same thing as 2., but for the time being,
> I would suggest that JOSM filters are your best best friend. And, thinking
> about how to tag things to make filtering easier is also a must. One thing
> I've started doing is tagging things with year tags... like y1855=yes for
> info that is shown on an 1855 map. Then, if data is shown on multiple maps,
> you can add y1878 (e.g.). Then, you can filter to just see things from that
> year.
>
> [image: image.png]
>
> Thanks & keep the questions coming!!
>
> Regards,
> Jeff
>
>
>
> On Wed, Sep 4, 2019 at 6:17 PM Guilherme Braga Alves <
> gbragaalves at gmail.com> wrote:
>
>> Hello guys!
>>
>> I found OpenHistoricalMap recently, and I'm having a great time with it.
>> I'm from Rio de Janeiro, and my first goal is to map the various lines of
>> trams we had in the city until the 1960s.
>>
>> This work has been easy, but I have faced some problems. Since I didn't
>> find answers in FAQs or similar things, I forward my doubts.
>>
>> 1. How do I map changes on the coastline? The history of Rio in the 20th
>> century is marked by numerous embankments on the waterfront, so the map
>> would be more interesting if it were possible to reproduce these changes.
>>
>> 1.a. Same for ponds and piped rivers. What should I do to reproduce these
>> changes over time?
>>
>> 2. One of the railroads I am mapping was built in 1878, but was not
>> electrified until 1945. Is there any way to insert two time frames into the
>> same object?
>>
>> 2.b. One of the trolley lines I mapped has been converted into a heavy
>> railroad track. Should I map two overlapping lines or is it possible to
>> time differentiate them using tags?
>>
>> Thank you for your attention.
>>
>> --
>> *Guilherme Braga Alves*
>> Bacharel em *Relações Internacionais* pela *UFRJ - Universidade Federal
>> do Rio de Janeiro*.
>> Mestre em *Políticas Públicas em Direitos Humanos* pelo *NEPP-DH/UFRJ -
>> Núcleo de Estudos de Políticas Públicas em Direitos Humanos da Universidade
>> Federal do Rio de Janeiro*.
>> Doutorando em *Geografia* pelo *IGEOG/UERJ - Instituto de Geografia da
>> Universidade do Estado do Rio de Janeiro*.
>> Telefone: (21) 97982-7869.
>>
>> _______________________________________________
>> Historic mailing list
>> Historic at openstreetmap.org
>> https://lists.openstreetmap.org/listinfo/historic
>>
>
>
> --
> Jeff Meyer
> 206-676-2347
> osm: Open Historical Map (OHM)
> <http://wiki.openstreetmap.org/wiki/Open_Historical_Map> / my OSM user
> page <http://www.openstreetmap.org/user/jeffmeyer>
> t: @OpenHistMap
>
>
>
>
>

-- 
*Guilherme Braga Alves*
Bacharel em *Relações Internacionais* pela *UFRJ - Universidade Federal do
Rio de Janeiro*.
Mestre em *Políticas Públicas em Direitos Humanos* pelo *NEPP-DH/UFRJ -
Núcleo de Estudos de Políticas Públicas em Direitos Humanos da Universidade
Federal do Rio de Janeiro*.
Doutorando em *Geografia* pelo *IGEOG/UERJ - Instituto de Geografia da
Universidade do Estado do Rio de Janeiro*.
Telefone: (21) 97982-7869.
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