On Friday 13 October 2017, Kevin Kenny wrote: > > I remain unconvinced that importing or not importing has had any > significant impact on whether people improve the map manually.
In case of NHD imports in the US there are certainly significant parts of the country where no NHD data has been imported and there is also no manual waterbody mapping worth mentioning - which would allow you to conclude there are likely also areas of NHD imports where at least so far this did not have a negative effect. But in areas of significant interest, in particular popular outdoor destinations, i am pretty sure you can observe this - i showed an example from southern Montana where the limit of the detailed and accurate manual mapping clearly matches the limit of the previous NHD import or in other words: The mapper mapping that clearly did not feel like bringing the NHD data to the same level of quality as the manually mapped area. This is just one case and you cannot simple conclude it is the same everywhere else but i would not simply dismiss the idea that there is a discouraging effect of imports on manual mapping in some cases. There are a number of possible measures that could be considered for improving old NHD imports: * removal of unnecessary tags to reduce the baggage mappers would have to deal with when working on the data. * removal of small unnamed streams which are not necessary for the overall river network connectivity in areas where the geometric accuracy is poor by current standards (and it is therefore usually easier for mappers to newly trace those streams instead of trying to improve the inaccurate data) * creating maproulette challenges for fixing inaccurate waterway classifications - in particular waterways tagged 'waterway=stream' but with a name containing 'Creek' or 'River' will often qualify as waterway=river. Same for artificial waterways with 'waterway=ditch' but names containing 'Canal' or ther other way round. * creating maproulette challenges for unconnected waterways. * adding missing 'intermittent=yes' to waterways in imports where this was not properly set based on the feature codes. -- Christoph Hormann http://www.imagico.de/ _______________________________________________ Talk-us mailing list [email protected] https://lists.openstreetmap.org/listinfo/talk-us
