<div dir="ltr">Guilherme - <div><br></div><div>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!!</div><div><br></div><div>So, you're hitting on some tough topics & I'll do my best to answer, </div><div><br></div><div>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: <a href="https://wiki.openstreetmap.org/wiki/Coastline">https://wiki.openstreetmap.org/wiki/Coastline</a> 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...</div><div><br></div><div>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: <a href="http://openhistoricalmap-1936150974.us-east-1.elb.amazonaws.com/#map=17/47.59962/-122.33220&layers=O">http://openhistoricalmap-1936150974.us-east-1.elb.amazonaws.com/#map=17/47.59962/-122.33220&layers=O</a></div><div><br></div><div>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.<br></div><div><br></div><div>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.<br><br><div><img src="cid:ii_k06xr54p0" alt="image.png" width="510" height="367"><br></div></div><div><br></div><div>Thanks & keep the questions coming!!</div><div><br></div><div>Regards,</div><div>Jeff</div><div><br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Sep 4, 2019 at 6:17 PM Guilherme Braga Alves <<a href="mailto:gbragaalves@gmail.com">gbragaalves@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hello guys!<br><br>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.<br><br>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.<br><br>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.<br><br>1.a. Same for ponds and piped rivers. What should I do to reproduce these changes over time?<br><br>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?<br><br>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?<br><br>Thank you for your attention.<br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail-m_6714204812169076052gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div><div><b><font size="4" color="#073763">Guilherme Braga Alves</font></b></div></div><div><font size="1" color="#274e13">Bacharel em <b>Relações Internacionais</b> pela <b>UFRJ - Universidade Federal do Rio de Janeiro</b>.</font></div><div><span style="color:rgb(39,78,19);font-size:x-small">Mestre em </span><b style="color:rgb(39,78,19);font-size:x-small">Políticas Públicas em Direitos Humanos</b><span style="color:rgb(39,78,19);font-size:x-small"> pelo </span><b style="color:rgb(39,78,19);font-size:x-small">NEPP-DH/UFRJ - Núcleo de Estudos de Políticas Públicas em Direitos Humanos da Universidade Federal do Rio de Janeiro</b><span style="color:rgb(39,78,19);font-size:x-small">.</span><br></div><div><font color="#274e13" size="1">Doutorando</font><span style="color:rgb(39,78,19);font-size:x-small"> em <b>Geografia</b> pelo <b>IGEOG/UERJ - Instituto de Geografia da Universidade do Estado do Rio de Janeiro</b>.</span></div><div><font size="1" color="#274e13">Telefone: (21) 97982-7869.<br><br></font></div></div></div></div></div></div></div></div></div></div>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><font size="1">Jeff Meyer</font></div><div dir="ltr"><font size="1">206-676-2347<br></font><div><span style="font-size:x-small">osm: </span><a href="http://wiki.openstreetmap.org/wiki/Open_Historical_Map" style="font-size:x-small" target="_blank">Open Historical Map (OHM)</a><span style="font-size:x-small"> / </span><a href="http://www.openstreetmap.org/user/jeffmeyer" style="font-size:x-small" target="_blank">my OSM user page</a><br></div><div><div><font size="1">t: @OpenHistMap </font></div><div></div><div><br></div><div><br></div><div><font size="1"><br></font><br></div></div></div></div></div></div></div>