Re: [OSM-talk] Converting buildings from nodes to ways
On 29 December 2010 23:12, Anthony wrote: > On Wed, Dec 29, 2010 at 4:44 PM, andrzej zaborowski wrote: >> Well, this still needs a change in the database schema and the API >> because currently there's no such attribute that the editors could >> use. > > If you're going to change the database schema, I vote for just making > IDs unique across all object types. Dealing with enums in > relation_members makes constructing efficient joins such a pain. Personally I'd like to see that too, but a new attribute for storing object's ancestry gives a little more flexibility because objects can have multiple children or parents, for operations like way splits and joins. Cheers ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Converting buildings from nodes to ways
On Wed, Dec 29, 2010 at 4:44 PM, andrzej zaborowski wrote: > Well, this still needs a change in the database schema and the API > because currently there's no such attribute that the editors could > use. If you're going to change the database schema, I vote for just making IDs unique across all object types. Dealing with enums in relation_members makes constructing efficient joins such a pain. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Converting buildings from nodes to ways
On 29 December 2010 22:13, Dave F. wrote: > On 29/12/2010 20:17, andrzej zaborowski wrote: >> >> Hi Dave, >> >> On 29 December 2010 21:04, Dave F. wrote: >>> >>> On 29/12/2010 17:30, andrzej zaborowski wrote: On 29 December 2010 13:47, Dave F. wrote: > > On 23/12/2010 12:10, Laurence Penney wrote: >> >> I've been 'exploding' several building nodes into ways, > > City centres maps look so much better with polygon ways, don't they? > > To encourage this practice it would be useful if the R (replicate) key > in > Potlatch worked from nodes to ways. It could also copy the history. There's no way in the current database schema to copy history from nodes to ways. >>> >>> Hi andrzej >>> >>> Could you elaborate on this please? >>> >>> If you mean it can't currently be done, then yes, I know, that why I was >>> posting the email. >>> >>> If you mean it can't be implemented in the future, then that's a bit >>> disappointing. As OSM increases it mapping detail it would be a very >>> useful >>> addition. >> >> It could be implemented in the future but the request should not go to >> Potlatch authors because the issue deeper. So as far as I know the >> workings of OSM, it'd have to wait to at least API 0.7. >> >> Object history is attached to an object. Currently objects are >> referenced by id + object type and IDs are not unique accross types >> (node, way, relation). So the type is a property of an object, not a >> property of a revision of an object. Thus no object can go from one >> type to another without losing the history. > > I'm not sure if non unique ID's would be a problem as the user is selecting > specific entities to copy from & to . > > Lets take a node element of a hotel that's been edited 4 times. > > Someones remaps it as a polygon way & copies the tags & history with the R > key. > > The new way entity would only have to store the id tags of the node as > historic ie "this used to be a node entity with the the id of XYZ123" whilst > keeping the id it was given when created. I assumed by copying history you meant keeping the Id of the entity, but you suggest adding a new entity attribute to store the link to "what this used to be". Which is what I suggested too, earlier in the thread. Well, this still needs a change in the database schema and the API because currently there's no such attribute that the editors could use. My second comment is that the history of XYZ123 is never "closed", people can still edit XYZ123, so you'd have to store the id, the type and the version number from which this new way entity was "forked". Cheers, Andrew ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Converting buildings from nodes to ways
On 29/12/2010 21:13, Dave F. wrote: On 29/12/2010 20:17, andrzej zaborowski wrote: Hi Dave, On 29 December 2010 21:04, Dave F. wrote: On 29/12/2010 17:30, andrzej zaborowski wrote: On 29 December 2010 13:47, Dave F.wrote: On 23/12/2010 12:10, Laurence Penney wrote: I've been 'exploding' several building nodes into ways, City centres maps look so much better with polygon ways, don't they? To encourage this practice it would be useful if the R (replicate) key in Potlatch worked from nodes to ways. It could also copy the history. There's no way in the current database schema to copy history from nodes to ways. Hi andrzej Could you elaborate on this please? If you mean it can't currently be done, then yes, I know, that why I was posting the email. If you mean it can't be implemented in the future, then that's a bit disappointing. As OSM increases it mapping detail it would be a very useful addition. It could be implemented in the future but the request should not go to Potlatch authors because the issue deeper. So as far as I know the workings of OSM, it'd have to wait to at least API 0.7. Object history is attached to an object. Currently objects are referenced by id + object type and IDs are not unique accross types (node, way, relation). So the type is a property of an object, not a property of a revision of an object. Thus no object can go from one type to another without losing the history. I'm not sure if non unique ID's would be a problem as the user is selecting specific entities to copy from & to . Lets take a node element of a hotel that's been edited 4 times. Someones remaps it as a polygon way & copies the tags & history with the R key. The new way entity would only have to store the id tags of the node as historic ie "this used to be a node entity with the the id of XYZ123" whilst keeping the id it was given when created. When I mean 'historic' I mean storing it as a child node within the XML data. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Converting buildings from nodes to ways
On 29/12/2010 20:17, andrzej zaborowski wrote: Hi Dave, On 29 December 2010 21:04, Dave F. wrote: On 29/12/2010 17:30, andrzej zaborowski wrote: On 29 December 2010 13:47, Dave F.wrote: On 23/12/2010 12:10, Laurence Penney wrote: I've been 'exploding' several building nodes into ways, City centres maps look so much better with polygon ways, don't they? To encourage this practice it would be useful if the R (replicate) key in Potlatch worked from nodes to ways. It could also copy the history. There's no way in the current database schema to copy history from nodes to ways. Hi andrzej Could you elaborate on this please? If you mean it can't currently be done, then yes, I know, that why I was posting the email. If you mean it can't be implemented in the future, then that's a bit disappointing. As OSM increases it mapping detail it would be a very useful addition. It could be implemented in the future but the request should not go to Potlatch authors because the issue deeper. So as far as I know the workings of OSM, it'd have to wait to at least API 0.7. Object history is attached to an object. Currently objects are referenced by id + object type and IDs are not unique accross types (node, way, relation). So the type is a property of an object, not a property of a revision of an object. Thus no object can go from one type to another without losing the history. I'm not sure if non unique ID's would be a problem as the user is selecting specific entities to copy from & to . Lets take a node element of a hotel that's been edited 4 times. Someones remaps it as a polygon way & copies the tags & history with the R key. The new way entity would only have to store the id tags of the node as historic ie "this used to be a node entity with the the id of XYZ123" whilst keeping the id it was given when created. The other tag attributes such as amenity, name etc could be copied directly with no problems Cheers Dave F. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Converting buildings from nodes to ways
On 29 December 2010 13:47, Dave F. wrote: > On 23/12/2010 12:10, Laurence Penney wrote: >> >> I've been 'exploding' several building nodes into ways, > > City centres maps look so much better with polygon ways, don't they? > > To encourage this practice it would be useful if the R (replicate) key in > Potlatch worked from nodes to ways. It could also copy the history. There's no way in the current database schema to copy history from nodes to ways. Cheers ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Converting buildings from nodes to ways
On 23/12/2010 12:10, Laurence Penney wrote: I've been 'exploding' several building nodes into ways, City centres maps look so much better with polygon ways, don't they? To encourage this practice it would be useful if the R (replicate) key in Potlatch worked from nodes to ways. It could also copy the history. A similar problem of loosing the history occurs when I resize roundabouts using the parallel tool. Cheers Dave F. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Converting buildings from nodes to ways
Thanks for the comments, everybody. The reuse of the old node in the new way, though not of supreme elegance, seems a very nice hack and I'll use it from now on. - L ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Converting buildings from nodes to ways
At 2010-12-23 04:10, Laurence Penney wrote: I've been 'exploding' several building nodes into ways, based on splendid Bing imagery for Bristol. It is nice, isn't it? I've been lucky enough to have 25/30cm imagery from USGS in most of my area, but this 6cm stuff is awesome. And cheers to the implementation for JOSM - it's incredibly fast and agile. Truly an important step for OSM. I'm getting concerned about data loss, the fact that any external database accumulating information on such vulnerable nodes, e.g. [1], will only with difficulty and guesswork be able to match it to the way that replaced it. I favor using the existing node as part of the new way, then removing the tags from it. This preserves its history. However, I don't believe people should ever count on OSM IDs to be at all permanent - they aren't designed to be. There was a long discussion a while ago about using GUIDs for that if necessary. -- Alan Mintz ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Converting buildings from nodes to ways
On Thu, Dec 23, 2010 at 11:10 PM, Laurence Penney wrote: > * Is there a tagging convention to record node->way conversion, i.e. what was > this way's predecessor_node? I think it would be worthwhile to use relations here, to also address the general issue of different representations of the same thing (eg, train line vs individual train tracks, focal point of an area rather than just its centroid, entrances etc). Nothing has yet been proposed though. Steve ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Converting buildings from nodes to ways
Andrew Harvey gmail.com> writes: >I was advised on the newbies list a while ago to make that initial >node part of the new way. ie. you move the node to somewhere on the >edge of the building, then start tracing from that node. This means >the node isn't deleted and one can see where in the history this node >was converted from a lone node to part of a way. Sounds like a great idea - that way relations that included the old node will keep working too (though software may still need modifying to look at the way the node is part of). I have done the same thing when tracing outlines for railway stations. All that's needed now is editor support, e.g. an 'explode node to area' tool. -- Ed Avis ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Converting buildings from nodes to ways
I was advised on the newbies list a while ago to make that initial node part of the new way. ie. you move the node to somewhere on the edge of the building, then start tracing from that node. This means the node isn't deleted and one can see where in the history this node was converted from a lone node to part of a way. On Thu, Dec 23, 2010 at 11:10 PM, Laurence Penney wrote: > I've been 'exploding' several building nodes into ways, based on splendid > Bing imagery for Bristol. I'm getting concerned about data loss, the fact > that any external database accumulating information on such vulnerable nodes, > e.g. [1], will only with difficulty and guesswork be able to match it to the > way that replaced it. > > I know the subject's been brought up several times before, but I'd to know > the current state. > > * Is there a tagging convention to record node->way conversion, i.e. what was > this way's predecessor_node? > * If there is, has it been considered whether to allow JOSM to convert nodes > to ways? e.g. a square, centred on the destroyed node, aligned to the grid, > sized to 25% of the current window, prepopulated with the node's tags and a > predecessor_node. > * Has it been considered whether to add something at a deeper level? e.g. to > record entity type conversions in the OSM history system? > > thanks, > > - L > > [1] OpenMaps > http://lists.openstreetmap.org/pipermail/talk/2010-December/055387.html > > ___ > talk mailing list > talk@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk > ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Converting buildings from nodes to ways
On 23 December 2010 13:10, Laurence Penney wrote: > I've been 'exploding' several building nodes into ways, based on splendid > Bing imagery for Bristol. I'm getting concerned about data loss, the fact > that any external database accumulating information on such vulnerable nodes, > e.g. [1], will only with difficulty and guesswork be able to match it to the > way that replaced it. > > I know the subject's been brought up several times before, but I'd to know > the current state. > > * Is there a tagging convention to record node->way conversion, i.e. what was > this way's predecessor_node? > * If there is, has it been considered whether to allow JOSM to convert nodes > to ways? e.g. a square, centred on the destroyed node, aligned to the grid, > sized to 25% of the current window, prepopulated with the node's tags and a > predecessor_node. I think a tag or database attribute (this would obviously need to wait for the next API version) like predecessor=[;[...]] (e.g. node:84264734) would be useful. It would be specially useful if JOSM added it automatically to ways that are being split, merged etc. There may be arguments that this would be just bloat for the database but in fact it'd just be an improvement to the way history is kept (without bearing on the advantages or disadvantages of keeping history in general). Cheers ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
[OSM-talk] Converting buildings from nodes to ways
I've been 'exploding' several building nodes into ways, based on splendid Bing imagery for Bristol. I'm getting concerned about data loss, the fact that any external database accumulating information on such vulnerable nodes, e.g. [1], will only with difficulty and guesswork be able to match it to the way that replaced it. I know the subject's been brought up several times before, but I'd to know the current state. * Is there a tagging convention to record node->way conversion, i.e. what was this way's predecessor_node? * If there is, has it been considered whether to allow JOSM to convert nodes to ways? e.g. a square, centred on the destroyed node, aligned to the grid, sized to 25% of the current window, prepopulated with the node's tags and a predecessor_node. * Has it been considered whether to add something at a deeper level? e.g. to record entity type conversions in the OSM history system? thanks, - L [1] OpenMaps http://lists.openstreetmap.org/pipermail/talk/2010-December/055387.html ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
