Thanks Mark, not only for the solutions but also the explanations. Very helpful.
On Wed, 6 Nov 2019 at 23:16, Mark Tully <[email protected]> wrote: > Hi Brian, > > Regarding your overpass issue, there's some optimizing of the query that > could help you if all you need is to count the number of relations. The > overpass wizard, by default, requests the tags, ids and geometry of the > objects which match the query. However, there are other options. > > These three lines are at the bottom of the default wizard queries: > out body; > >; > out skel qt; > > They basically mean "send back all the details of the selected objects and > the geometry of their child objects" (the elements of the relations in most > cases) This allows them to be displayed on the map. We can request that > overpass sends us less data by changing these 3 lines. If you remove them, > then you're requesting overpass to send you nothing, as you found out. > > There's 3 main useful options > 1: Replace the 3 lines with "out center qt;" - This will display the centre > of each townland rather than its boundaries > 2: Replace the 3 lines with "out tags qt;" - This will show only the tags > of the results, so they won't show up on the map. However, the map will > still show how many objects were loaded, even though they don't appear. > 3: Replace the 3 lines with "out ids qt;" - This will only show the ids of > the results. As with 2, they won't show up on the map, but it will still > show how many objects were loaded. > > Obviously, each approach has less and less data being transferred to the > browser, making it easier to display it (and saving some network traffic). > For example, using approach 3 on the query for Munster, the data is reduced > from ~100Mb to <1 Mb, which is significant if you don't need to actually > see the geometries of the queried items. > > Hope this helps, > Mark > > On Wed, Nov 6, 2019 at 6:13 PM Brian Hollinshead <[email protected]> > wrote: > > > I often use this to count features, say locality=townland in Louth. > > > > Works fine but I tried it for Munster and 100mB was rather too much to > > display. I removed the last three lines to avoid a display but then it > does > > not count. > > > > Perhaps one of you has a way around this please? > > > > I am also looking for a textual description of what constitutes > traditional > > Connamara, based perhaps on DEDs or Civil parishes etc. Does it > correspond > > with the new Connemara Municipal District? > > _______________________________________________ > > Talk-ie mailing list > > [email protected] > > https://lists.openstreetmap.org/listinfo/talk-ie > > > _______________________________________________ > Talk-ie mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/talk-ie > _______________________________________________ Talk-ie mailing list [email protected] https://lists.openstreetmap.org/listinfo/talk-ie
