OpenStreetMap
After an absence of a few months I've noticed a significant improvement in the speed at which changes made with JOSM appear in the Web-rendered view of OpenStreetMap. However, some of the drawing tools still leave much to be desired, especially for someone who is familiar with commercial CAD packages. The Web view can be panned by clicking on the map, holding the mouse button down and moving the map. JOSM is driving me crazy with its silly zoom out / zoom in paradigm. If one is attempting to maintain the proper scale, it is very difficult to do, as I've been unable to discover a means for zooming to a preset factor; every time I zoom out and back in, the scale is essentially a random number.
I've also noticed some strange anomalies on the map, such as features off their proper locations by hundreds of meters and mangled boundaries. The contours of some of the city limits boundaries of Morgan Hill lead me to believe that vandals have been at work, since they make no sense and don't conform to recently published maps from authoritative sources. I've also noticed some relatively unimportant features, such as man-made percolation ponds, with a level of detail 5x to 10x what is needed to depict them; again, it's likely the result of vandalism or juvenile experimentation. The jokers apparently didn't catch the drift that this is the OpenStreetMap project, with emphasis on STREET, not a GIS database for civil engineers, and that adding excessive detail clutters the database and makes rendering slower.
Discussion
Comment from joakimfors on 17 November 2011 at 01:32
Don't know if I'm misinterpreting you but to pan in JOSM just hold down the right mouse button and drag.
I don't either see a problem in having a lot of details for non-street objects. I regularly use OSM when out hiking or biking and it is nice to have a lot of small details to help locate yourself even if you have GPS lock. However, it's best to keep the general detail level of an area the same when mapping.
BTW, real, non-reduced, admin boundaries can be quite weird sometimes. :)
Comment from Vclaw on 17 November 2011 at 02:02
It sounds like most of those strange anomalies are from the US TIGER import. osm.wiki/TIGER
It can be very inaccurate or out of date in some places. You can look at any source tags, or the history of the objects to check where its from. Its probably not jokers or vandals, just wrong official government data. TIGER data in OSM should be checked and fixed where possible.
Also despite the name, OpenStreetMap is not just a street map. There is loads of other geographical data in the project, and it is welcome. Database clutter is not really a problem, extra detail doesn't really slow down rendering.
Though if you have something like a small pond mapped with hundreds or thousands of nodes that would probably be excessive. That sort of thing is probably from an unhelpful import, eg TIGER.
Comment from user8192 on 17 November 2011 at 21:38
@joakimfors Thanks for the tip! The right mouse button does it — click and hold while moving the cursor. It will make editing much less tedious.
Comment from nichlas on 16 January 2012 at 14:13
Rendering is not being made slower by adding details, as only selected details are actually being rendered on maps like openstreetmap.org and so on.
It should only be slower on applications like JOSM, where you can opt to only get specific subsets of the data when you are working.
Comment from user8192 on 19 January 2012 at 18:27
@nichlas That would be a first. I've been using AutoCAD for over 20 years, and electrical/electronic vector CAD programs for a similar length of time, and increasing drawing database size and complexity ALWAYS increases rendering/redrawing/regeneration time. Perhaps you don't notice it if you're on a very fast network connection with a "bleeding edge" multi-core computer and are looking at a tiny slice of OpenStreetMap, but the typical user will see delays and slower performance as drawing complexity increases.