Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
On 27/07/2015 20:23, Jochen Topf wrote: This is more about the water flow than about being navigable by a ship. Indeed. Given that the waterway tagging rules cited in the OP applies equally to streams, ditches & drains, then the routability clearly does not imply navigability, merely continuity of the watercourse, obstructions such as weirs, sluices, locks, etc not withstanding. ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
Before doing the actual routing, the polygon for the "whole lake" must be preprocessed in various ways: eliminate areas which are too shallow, prohibited, one-way/wrong-way, subject to traffic controls etc. Then the routing algorithm can avoid all these no-go areas, just as if they were physical obstacles. There is probably an equivalent of "access=private", "access=permissive" and "access=destination" as well. --colin On 2015-07-28 16:03, John Eldredge wrote: > In some cases, the navigation path may be different from the named waterway, > such as when locks and canals are used to bypass waterfalls or rapids. In > the case of reservoirs and lakes, some areas may be too shallow for > navigation, so the actual navigation route may not always be the shortest > path between the inlet and outlet points. > > -- > John F. Eldredge -- j...@jfeldredge.com > "Darkness cannot drive out darkness; only light can do that. Hate cannot > drive out hate; only love can do that." -- Martin Luther King, Jr. > > On July 27, 2015 2:25:54 PM Jochen Topf wrote: > > On Mo, Jul 27, 2015 at 08:08:22 +0100, Lester Caine wrote: On 27/07/15 19:56, > Christoph Hormann wrote: In the case where a stream flows into a reservoir , > and then a stream (with the same name) also flows out of that reservoir, > should a > linear way be drawn through the reservoir to connect the two streams > (the reservoir is currently represented by its own closed way tagged > natural=water, water=reservoir)? > Yes. Although a height difference between in and out might indicate a weir or other obstruction may well indicate that a route is non-navigable? The outflow from a dam may have the same name, but have no use as a through route? This is more about the water flow than about being navigable by a ship. Jochen -- Jochen Topf joc...@remote.org http://www.jochentopf.com/ +49-351-31778688 ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
In some cases, the navigation path may be different from the named waterway, such as when locks and canals are used to bypass waterfalls or rapids. In the case of reservoirs and lakes, some areas may be too shallow for navigation, so the actual navigation route may not always be the shortest path between the inlet and outlet points. -- John F. Eldredge -- j...@jfeldredge.com "Darkness cannot drive out darkness; only light can do that. Hate cannot drive out hate; only love can do that." -- Martin Luther King, Jr. On July 27, 2015 2:25:54 PM Jochen Topf wrote: On Mo, Jul 27, 2015 at 08:08:22 +0100, Lester Caine wrote: > On 27/07/15 19:56, Christoph Hormann wrote: > >> In the case where a stream flows into a reservoir , and then a stream > >> > (with the same name) also flows out of that reservoir, should a > >> > linear way be drawn through the reservoir to connect the two streams > >> > (the reservoir is currently represented by its own closed way tagged > >> > natural=water, water=reservoir)? > > > Yes. > > Although a height difference between in and out might indicate a weir or > other obstruction may well indicate that a route is non-navigable? The > outflow from a dam may have the same name, but have no use as a through > route? This is more about the water flow than about being navigable by a ship. Jochen -- Jochen Topf joc...@remote.org http://www.jochentopf.com/ +49-351-31778688 ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
On 28/07/2015 10:24 PM, Christoph Hormann wrote: On Tuesday 28 July 2015, Maarten Deen wrote: Do you think that hydrological analysis is a wider field of application than water navigation? I was of the opinion that the connection of waterways within OSM was primarily for navigation. That certainly depends on your point of view and metric used but it is not unreasonable to think it is, especially considering that most of the waterbody data in OSM represents non-navigable waterbodies. I have for quite some time now pointed out that in terms of visualization if you want to do more with the OSM water data than just draw everything in uniform color a full water flow network is the basis of almost everything you might want to do. In particular any differentiated rendering depends on a consistent importance rating which can only be produced based on water flow analysis. As some maps show height data for elevation of hills, mountains etc so other maps show depth data for seas, oceans. I think it would be easier to map the depth data, flow rates will vary more with tides and rainfall than the actual depth. It would be interesting to have the flow rate evaluated here https://en.wikipedia.org/wiki/Horizontal_Falls where the tide reaches 10 m. And of course the flow reverses from hi tide to low tide. Difficult to map. ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
On Tuesday 28 July 2015, Maarten Deen wrote: > > Do you think that hydrological analysis is a wider field of > application than water navigation? > I was of the opinion that the connection of waterways within OSM was > primarily for navigation. That certainly depends on your point of view and metric used but it is not unreasonable to think it is, especially considering that most of the waterbody data in OSM represents non-navigable waterbodies. I have for quite some time now pointed out that in terms of visualization if you want to do more with the OSM water data than just draw everything in uniform color a full water flow network is the basis of almost everything you might want to do. In particular any differentiated rendering depends on a consistent importance rating which can only be produced based on water flow analysis. -- Christoph Hormann http://www.imagico.de/ ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
On 2015-07-28 13:37, Christoph Hormann wrote: On Tuesday 28 July 2015, Colin Smale wrote: Hi Christoph, my suggestion was to clearly separate the subject of water flow from the subject of routing. Whether roads are mostly bidirectional or not is irrelevant I think, as routers have to be able to handle one-way roads anyway.[...] The requirement to connect waterways within water areas to create a routable network is primarily about water flow and not about water navigation. If you want to discuss the needs for water navigation that is fine but any results of such discussion will have little bearing on the suggestion to link waterways to create a routable network. Do you think that hydrological analysis is a wider field of application than water navigation? I was of the opinion that the connection of waterways within OSM was primarily for navigation. Regards, Maarten ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
On 28/07/15 10:11, Martin Koppenhoefer wrote: >> but have no use as a through route? > > the water will undoubtedly pass through on its "route" Flow management from man made reservoirs may tend to modify that situation. -- Lester Caine - G8HFL - Contact - http://lsces.co.uk/wiki/?page=contact L.S.Caine Electronic Services - http://lsces.co.uk EnquirySolve - http://enquirysolve.com/ Model Engineers Digital Workshop - http://medw.co.uk Rainbow Digital Media - http://rainbowdigitalmedia.co.uk ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
On Tuesday 28 July 2015, Colin Smale wrote: > Hi Christoph, my suggestion was to clearly separate the subject of > water flow from the subject of routing. Whether roads are mostly > bidirectional or not is irrelevant I think, as routers have to be > able to handle one-way roads anyway.[...] The requirement to connect waterways within water areas to create a routable network is primarily about water flow and not about water navigation. If you want to discuss the needs for water navigation that is fine but any results of such discussion will have little bearing on the suggestion to link waterways to create a routable network. The use of the term 'routable' is just because water flow analysis is technically similar to the routing algorithms used for navigation. I brought up the concept of oneway roads just to illustrate to those familiar with routing for navigation the problems arising from having components of the network represented by undirected polygon geometries. -- Christoph Hormann http://www.imagico.de/ ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
Hi Christoph, my suggestion was to clearly separate the subject of water flow from the subject of routing. Whether roads are mostly bidirectional or not is irrelevant I think, as routers have to be able to handle one-way roads anyway. If I understand it right, edges in routing graphs are often one-way anyway as the characteristics from A to B may be different from B to A. If you are interested in hydrodynamics on a large scale, like predicting the route an unpowered floating object would take, that is entirely different to the use of a routing engine to suggest a route to the skipper of a boat. Simply adding a way from one side of a lake to the other to stop some QA program complaining is bordering on tagging for the renderer... --colin On 28 July 2015 11:17:00 CEST, Christoph Hormann wrote: >On Tuesday 28 July 2015, Colin Smale wrote: >> If we can separate the flow direction discussion from the routing, >> the latter becomes a more generic "routing through areas" problem >> which has been discussed before in the context of pedestrian routing. > >Water flow structure is not only about flow direction of individual >segments, it is also about connectivity - hence the routable network. > >And yes, you can try to take polygons into account to determine >waterflow - you have to at the moment since missing line mapping is >just too widespread. But for non-trivial polygons (i.e. ones with >holes or areas represented by multiple polygons) this is generally >ambiguous and it is hard to analyze as well. > >The analogy between water flow analysis and traffic routing is >misleading here since traffic routes are mostly bidirectional. If you >imagine a road network exclusively built from oneway roads you can >immediately see that having parts of that network represented as >polygons will make routing difficult. > >And - this is even more important - it also makes it difficult to spot >errors in mapping. If you have a full line mapping of a river network >it is very easy to identify problems locally for QA tools or validators > >in editors - just like in case of the coastline. If you rely on >polygon features creating connectivity in the waterflow network you >need to analyze it in full before you are able to spot where mapping is > >broken. > >-- >Christoph Hormann >http://www.imagico.de/ > >___ >talk mailing list >talk@openstreetmap.org >https://lists.openstreetmap.org/listinfo/talk ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
On Tuesday 28 July 2015, Colin Smale wrote: > If we can separate the flow direction discussion from the routing, > the latter becomes a more generic "routing through areas" problem > which has been discussed before in the context of pedestrian routing. Water flow structure is not only about flow direction of individual segments, it is also about connectivity - hence the routable network. And yes, you can try to take polygons into account to determine waterflow - you have to at the moment since missing line mapping is just too widespread. But for non-trivial polygons (i.e. ones with holes or areas represented by multiple polygons) this is generally ambiguous and it is hard to analyze as well. The analogy between water flow analysis and traffic routing is misleading here since traffic routes are mostly bidirectional. If you imagine a road network exclusively built from oneway roads you can immediately see that having parts of that network represented as polygons will make routing difficult. And - this is even more important - it also makes it difficult to spot errors in mapping. If you have a full line mapping of a river network it is very easy to identify problems locally for QA tools or validators in editors - just like in case of the coastline. If you rely on polygon features creating connectivity in the waterflow network you need to analyze it in full before you are able to spot where mapping is broken. -- Christoph Hormann http://www.imagico.de/ ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
sent from a phone > Am 27.07.2015 um 21:08 schrieb Lester Caine : > > but have no use as a through > route? the water will undoubtedly pass through on its "route" ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
If we can separate the flow direction discussion from the routing, the latter becomes a more generic "routing through areas" problem which has been discussed before in the context of pedestrian routing. The idea being that it should be possible to construct a routing engine to take you from any point on an edge of a polygon to any other such point, while remaining within the polygon boundary. An alternative is a full mesh network, where every possible entry node is directly connected to every possible exit node. --colin On 28 July 2015 08:01:51 CEST, Maarten Deen wrote: >On 2015-07-27 23:39, Lester Caine wrote: >> On 27/07/15 20:55, Mike Thompson wrote: >>> I assumed that when the wiki spoke about "routable" it was referring > >>> to >>> the water flow rather than boat/ship/barge traffic. In any event, >a >>> routing engine for boats could use the presence of a dam or weir >>> (combined with the absence of a lock) to deduce that ship navigation > >>> was >>> not possible. >> >> 'This way used should point in the direction of water flow' is only >> applicable to non-tidal flows, and reservoirs may well control water >> flow in a way that makes a 'water flow map' somewhat difficult to >> deduce. > >Only if they are entirely artificial. A dam in a river or stream makes >the direction of water very clear: high to low. Only when there is an >artificial reservoir with no natural tributary it is not clear. > >> The use of 'routable network' is rather ambiguous, but this is little >> different to the problem of routing through other land based open >areas >> where several waterway features link into an area of open water. The >> jury is still out on putting in all the paths through the area, but >if >> there is a navigable route designated through a water body it should >be >> drawn, but an imaginary link just showing water flow should not be >> necessary? Any routing process should be able to deduce the relation, >> there is no need to draw it. > >Causality. Does a water area need a way indicating the direction of >water? Of is it that when you draw a way through the water area it >should point in the direction of the water flow. > >Maarten > > > > >___ >talk mailing list >talk@openstreetmap.org >https://lists.openstreetmap.org/listinfo/talk ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
On 2015-07-27 23:39, Lester Caine wrote: On 27/07/15 20:55, Mike Thompson wrote: I assumed that when the wiki spoke about "routable" it was referring to the water flow rather than boat/ship/barge traffic. In any event, a routing engine for boats could use the presence of a dam or weir (combined with the absence of a lock) to deduce that ship navigation was not possible. 'This way used should point in the direction of water flow' is only applicable to non-tidal flows, and reservoirs may well control water flow in a way that makes a 'water flow map' somewhat difficult to deduce. Only if they are entirely artificial. A dam in a river or stream makes the direction of water very clear: high to low. Only when there is an artificial reservoir with no natural tributary it is not clear. The use of 'routable network' is rather ambiguous, but this is little different to the problem of routing through other land based open areas where several waterway features link into an area of open water. The jury is still out on putting in all the paths through the area, but if there is a navigable route designated through a water body it should be drawn, but an imaginary link just showing water flow should not be necessary? Any routing process should be able to deduce the relation, there is no need to draw it. Causality. Does a water area need a way indicating the direction of water? Of is it that when you draw a way through the water area it should point in the direction of the water flow. Maarten ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
On 27/07/15 20:55, Mike Thompson wrote: > I assumed that when the wiki spoke about "routable" it was referring to > the water flow rather than boat/ship/barge traffic. In any event, a > routing engine for boats could use the presence of a dam or weir > (combined with the absence of a lock) to deduce that ship navigation was > not possible. 'This way used should point in the direction of water flow' is only applicable to non-tidal flows, and reservoirs may well control water flow in a way that makes a 'water flow map' somewhat difficult to deduce. The use of 'routable network' is rather ambiguous, but this is little different to the problem of routing through other land based open areas where several waterway features link into an area of open water. The jury is still out on putting in all the paths through the area, but if there is a navigable route designated through a water body it should be drawn, but an imaginary link just showing water flow should not be necessary? Any routing process should be able to deduce the relation, there is no need to draw it. -- Lester Caine - G8HFL - Contact - http://lsces.co.uk/wiki/?page=contact L.S.Caine Electronic Services - http://lsces.co.uk EnquirySolve - http://enquirysolve.com/ Model Engineers Digital Workshop - http://medw.co.uk Rainbow Digital Media - http://rainbowdigitalmedia.co.uk ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
> > > Although a height difference between in and out might indicate a weir or > > other obstruction may well indicate that a route is non-navigable? The > > outflow from a dam may have the same name, but have no use as a through > > route? > > This is more about the water flow than about being navigable by a ship. > > I assumed that when the wiki spoke about "routable" it was referring to the water flow rather than boat/ship/barge traffic. In any event, a routing engine for boats could use the presence of a dam or weir (combined with the absence of a lock) to deduce that ship navigation was not possible. ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
On Mo, Jul 27, 2015 at 08:08:22 +0100, Lester Caine wrote: > On 27/07/15 19:56, Christoph Hormann wrote: > >> In the case where a stream flows into a reservoir , and then a stream > >> > (with the same name) also flows out of that reservoir, should a > >> > linear way be drawn through the reservoir to connect the two streams > >> > (the reservoir is currently represented by its own closed way tagged > >> > natural=water, water=reservoir)? > > > Yes. > > Although a height difference between in and out might indicate a weir or > other obstruction may well indicate that a route is non-navigable? The > outflow from a dam may have the same name, but have no use as a through > route? This is more about the water flow than about being navigable by a ship. Jochen -- Jochen Topf joc...@remote.org http://www.jochentopf.com/ +49-351-31778688 ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
On 27/07/15 19:56, Christoph Hormann wrote: >> In the case where a stream flows into a reservoir , and then a stream >> > (with the same name) also flows out of that reservoir, should a >> > linear way be drawn through the reservoir to connect the two streams >> > (the reservoir is currently represented by its own closed way tagged >> > natural=water, water=reservoir)? > Yes. Although a height difference between in and out might indicate a weir or other obstruction may well indicate that a route is non-navigable? The outflow from a dam may have the same name, but have no use as a through route? -- Lester Caine - G8HFL - Contact - http://lsces.co.uk/wiki/?page=contact L.S.Caine Electronic Services - http://lsces.co.uk EnquirySolve - http://enquirysolve.com/ Model Engineers Digital Workshop - http://medw.co.uk Rainbow Digital Media - http://rainbowdigitalmedia.co.uk ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] waterway - "routable network" and reservoirs/lakes
On Monday 27 July 2015, Mike Thompson wrote: > The wiki states that the linear features representing waterways > should "connect with other linked waterway features to create a > routable network." [1] > In the case where a stream flows into a reservoir , and then a stream > (with the same name) also flows out of that reservoir, should a > linear way be drawn through the reservoir to connect the two streams > (the reservoir is currently represented by its own closed way tagged > natural=water, water=reservoir)? Yes. -- Christoph Hormann http://www.imagico.de/ ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
[OSM-talk] waterway - "routable network" and reservoirs/lakes
The wiki states that the linear features representing waterways should "connect with other linked waterway features to create a routable network." [1] In the case where a stream flows into a reservoir , and then a stream (with the same name) also flows out of that reservoir, should a linear way be drawn through the reservoir to connect the two streams (the reservoir is currently represented by its own closed way tagged natural=water, water=reservoir)? [1] https://wiki.openstreetmap.org/wiki/Waterways#Linear_water_features:_rivers.2C_canals.2C_streams_etc Mike ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
