I've been looking at the NHD data from the USGS site and have noticed a few recent changes from how they were described on the wiki.
1. The viewer has changed. http://viewer.nationalmap.gov/viewer/nhd.html will bring up a map you can use to download NHD data. This viewer does not work in Chrome but does work in IE. Subregions are pre-staged downloads, the others will take some time before you can download. Subregions can be directly downloaded from ftp://nhdftp.usgs.gov/DataSets/Staged/SubRegions/PersonalGDB/HighResolution/ Most subregions are available as a new NHD 931v210 file but some are still being generated. 2. NHD data is now available only as File Geodatabases (File GDBs, .gdb) and Personal Geodatabases (Personal GDBs, .mdb). My understanding is the default builds of QuantumGIS and GDAL on Windows can open Personal GDBs. On linux gdal can be compiled with drv_mdb or the pgeo driver can be used for Personal GDBs, or the filegdb driver can be used for File GDBs. This is moderately technical. 3. The NHD attributes changed with NHD v2.1. All the old mappings of NHD FCodes to OSM tags are outdated. For rivers and streams nothing has changed but others have. I haven't found a list of the 2012 changes. The two current FCode lists I am aware of are http://nhd.usgs.gov/userGuide/Robohelpfiles/NHD_User_Guide/Feature_Catalog/H ydrography_Dataset/Complete_FCode_List.htm and http://nhd.usgs.gov/NHDv2.1_poster_3_23_2012.pdf If you are planning something where you will be checking each object's tagging this will not affect you too much, although you may encounter more objects you have to retag. If you are considering proposing any kind of NHD import where you don't check each option I suggest you wait. I am working on a translation file but it takes a fair amount of time. There are a *lot* of FCodes and I need to look at some of each in multiple areas to see the appropriate tagging. Not all FCodes appear in all areas and what seems appropriate in one area may not be for all areas. _______________________________________________ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
