<div dir="ltr"><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">But you can't decide something about OSM on the HOT mailing list. You can confer and edit the wiki but that may or may not be followed. There are a number of instances where what is suggested in the wiki and taginfo are quite different.<br><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">Data compression was mentioned purely because of the writer showing up as a computer science / engineer person. Having worked in computers including setting standards for some years cost is something they don't always consider and it is a major part of engineering. No matter what compression system is used four nodes will always take up four times the space as one node. Maybe not with .7z compression looking for strings in the long lat but its a good rule of thumb. Again OSM is now running the largest database known in whatever it is running in, I forget the name. It's really big which means bleeding edge as we used to call it for backups, for data retrieval etc.. Not quite where you want to be for reliability.<br><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">I've seen some areas / projects where building outlines are mapped accurately. Ottawa, Canada is one, the data was imported from local government sources.<font size="2"><span style="font-weight:normal"> Lusaka, Zambia, they used motivated experienced GIS people but having said I've done a lot of validation and accurately mapped buildings are not infrequent on a HOT project.<br><br></span></font></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small"><font size="2"><span style="font-weight:normal">The biggest users of nodes for buildings on HOT projects are experienced OSM mappers. They will switch to ways when you give them feedback that that is what HOT prefers but I think they are the largest source. The HOT training group has done a very good job on training HOT mappers to draw ways.<br></span></font></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small"><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">Cheerio John<br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small"><br><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On 22 May 2017 at 14:16, Jan Martinec <span dir="ltr"><<a href="mailto:jan@martinec.name" target="_blank">jan@martinec.name</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class=""><div dir="auto"><div style="font-family:sans-serif" dir="auto"><div dir="auto">Hello all,</div><div dir="auto"><br></div>There's really no "their" where OSM is concerned - the database is made by individual contributors, without centralized oversight, and much of the mapping is by convention. But looking at the OSM wiki gives some fairly strong recommendations: <a href="http://wiki.openstreetmap.org/wiki/Key:building" target="_blank">http://wiki.o<wbr>penstreetmap.org/wiki/Key:buil<wbr>ding</a> - to paraphrase, "in absence of better data, building-as-a-node is better than nothing at all, until it can be mapped as an area from a better source."</div><div dir="auto" style="font-family:sans-serif"><br></div><div dir="auto" style="font-family:sans-serif">As far as "accurate mapping" - that's a problem and a driving force for the whole of OSM: have you seen the map in 2010? There was a very similar situation worldwide, with most buildings existing as rough outlines or not at all; requiring "perfect or nothing" would have resulted in no OSM, period.</div><div dir="auto" style="font-family:sans-serif"><br></div><div dir="auto" style="font-family:sans-serif">That said, the quality of mapping does depend on feedback, especially with new mappers: is the project with badly mapped buildings representative of HOT projects? The ones I've seen (and edited) seem to match building shapes and sizes well - e.g. <a href="http://tasks.hotosm.org/project/2520" target="_blank">http://tasks.hotosm.org/p<wbr>roject/2520</a> - but that's also an issue of task validation, in addition to mapper training; I do agree that takes some additional human power in return for much better map result.</div><div dir="auto" style="font-family:sans-serif"><br></div><div dir="auto" style="font-family:sans-serif">So, I guess that where time is critical (or space, even though XML compresses well and data for mobile apps is compressed even more efficiently), buildings-as-nodes are an acceptable interim solution, but the ideal case is buildings as well-outlined ways (which is what "experienced OSM mappers" do prefer, btw; no retraining needed).</div><div dir="auto" style="font-family:sans-serif"><br></div><div dir="auto" style="font-family:sans-serif">Cheers,</div><div dir="auto" style="font-family:sans-serif">Jan "Piskvor" Martinec,</div><div dir="auto" style="font-family:sans-serif">OSM and HOTOSM mapper</div></div></span><div class="gmail_extra"><br><div class="gmail_quote"><span class="">Dne 22. 5. 2017 17:54 napsal uživatel "john whelan" <<a href="mailto:jwhelan0112@gmail.com" target="_blank">jwhelan0112@gmail.com</a>>:<br type="attribution"></span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">But from your computer science background you should realise there are costs involved. To mark a building as a node is one line in the database. As a way well there are four nodes for a start each with its lat and long, then you have the connecting way. Have you saved a bit of .OSM and opened it in Notepad++? Try it sometime. Open JOSM download a tiny area ie a building and take a look. Download a node and take another look.<br><br></div><div><div class="h5"><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">So we have time costs in mapping, plus internet costs in uploading the additional information, storage in the main OpenStreetMap database, additional costs in downloading, more storage required on smartphones in the field more processing required at all stages. The time costs in mapping mean given the number of mappers we have few projects will get mapped. We also have experienced OpenStreetMap mappers mapping who may not follow HOT guidelines. These will need retraining and how will you reach them?<br><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">In Africa internet transmission costs are much higher than locally in North America so ideally we want to minimise these. <br><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">Then you get to the added value.<br><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">Take a look at <a href="http://tasks.hotosm.org/project/2656#task/102" target="_blank">http://tasks.hotosm.org/projec<wbr>t/2656#task/102</a> when I validated it recently for a highways project it seemed to me that most buildings=yes were twice or three times the size of the building sometimes covering more than one building, at least they were mostly square. For HOT projects this is not untypical but strange shapes tagged building=yes abound. I've seen tiles when only half the buildings have been mapped but the tile marked done.<br><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">The true added value is being able to estimate population. How many people are there that need to be vaccinated. If the buildings are mapped accurately then you stand a chance. You may have seen some references to the JOSM building_tool plugin, try it if you haven't. You take the number of buildings and their combined area and you can make some reasonable guesses. The area data is so unreliable you might as well have asked for nodes and to be honest you stand a better chance of them all being mapped.<br><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">I take it you took all these points into consideration before saying that building=yes nodes should not be used?<br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small"><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">The place to raise the issue is with OpenStreetMap, its their map and there will be different points of view and it might be worth checking how many there are in the map already.<br><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">Cheerio John<br></div></div></div></div><div><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On 22 May 2017 at 11:18, Enock Seth Nyamador <span dir="ltr"><<a href="mailto:kwadzo459@gmail.com" target="_blank">kwadzo459@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small">On personal level I feel mapping buildings as nodes is very wrong so I avoid it. </div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small">But I think tagging nodes as building should be looked at very well. I will recommend it is deprecated.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small">Best,</div></div><div class="gmail_extra"><br clear="all"><div><div class="m_2841170680771582702m_-3485946186446223197m_-3103392877728901351gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>- Enock<br></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div><div><div class="m_2841170680771582702m_-3485946186446223197h5">
<br><div class="gmail_quote">2017-05-20 11:38 GMT+00:00 Vao Matua <span dir="ltr"><<a href="mailto:vaomatua@gmail.com" target="_blank">vaomatua@gmail.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">My opinion is that buildings should be mapped as areas.<div>In un-mapped areas it would be best to create landuse=residential areas first rather than quickly tagging buildings with single nodes. When it comes time to trace buildings it is troublesome to convert single nodes to polygons.</div><div>For existing single node areas they could be cleaned up on an as-needed basis.</div><div><br></div><div>Emmor</div><div>(Palolo)</div></div><div class="m_2841170680771582702m_-3485946186446223197m_-3103392877728901351HOEnZb"><div class="m_2841170680771582702m_-3485946186446223197m_-3103392877728901351h5"><div class="gmail_extra"><br><div class="gmail_quote">On Sat, May 20, 2017 at 2:10 PM, Bjoern Hassler <span dir="ltr"><<a href="mailto:bjohas+mw@gmail.com" target="_blank">bjohas+mw@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Dear both, dear all,<div><br></div><div>If we're agreed that it's better to map buildings as areas - should we try to re-map node-buildings from previous campaigns as areas? Or shall we just leave it?<br><div><br></div><div>Many thanks,</div><div>Bjoern</div></div><div class="gmail_extra"><br><div class="gmail_quote">On 19 May 2017 at 17:54, Cascafico Giovanni <span dir="ltr"><<a href="mailto:cascafico@gmail.com" target="_blank">cascafico@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><p dir="ltr">AFAIK Osmand renders addr: housenumber also for polygons [1].</p>
<p dir="ltr">Anyway I agree to the general rule that rendering has to adhere to mapping (and not VS).<br></p>
<p dir="ltr">[1] <a href="http://cascafico.altervista.org/public/Screenshot_2017-05-19-18-40-41.png" target="_blank">cascafico.altervista.org/publi<wbr>c/Screenshot_2017-05-19-18-40-<wbr>41.png</a><br>
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