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.

I have been working the southwest area of Morgan Hill, California for the last few weeks and I have noticed a serious problem with the map renderers -- Mapnik, Osmarender, etc. Changes to streets take days to show up, or never show up. I go back to JOSM and check the database, and the changed data appear to be correct, but the renderers never pick them up. Even worse, the presentation varies by zoom level. I see streets and other features that have had their properties changed days earlier, and at certain zoom levels old data still persist. I'm assuming these are problems with the rendering algorithms, and not the underlying database. However, since most site visitors will see the map as a rendered presentation of the database, it seriously limits the usefulness of OpenStreetMap at present.

The weird lag or lack of proper rendering by zoom level seems to imply that the renderers are making multiple passes to render changes for a region and are somehow being interrupted in that task before all zoom levels have been covered, so the changes never show up to the end user. Perhaps this could be fixed, at least in the short term, by allowing editors to select a region, say, 1 km square or smaller, or select a specific way, and manually force the renderers to update views at all zoom levels within the box or length of the way. This could be handled as a queued background task, so as not to bog down the servers excessively.

A couple of weeks ago I was looking at Google Maps in the southeast area of Morgan Hill, California for assistance in updating OpenStreetMap. I found numerous errors, some of them rather severe, and reported them to Google for correction. Even though they acknowledged my submissions as being correct, so far nothing has changed when I look at the same area. Moreover, it seems that Google Maps was more accurate as recently as a year or two ago. They seem to have imported some new databases that are riddled with errors.

That said, OpenStreetMap has the potential to become much more accurate and useful than Google Maps. However, the aerial photography that is supplied by Yahoo! is terribly out of date. For instance, the new Morgan Hill Library was built in 2006-2007 and dedicated in July 2007. The aerial photo for the Morgan Hill Civic Center still shows a graded lot with some construction equipment around the edges, so it was probably shot in the late summer of 2006. That's nearly FOUR YEARS ago! What can we do to get new aerial or satellite imagery?

Joined OpenStreetMap project on 10 April 2010.

Cleaned up a few features in my neighborhood in Morgan Hill, California. Removed a maze of nonexistent streets between La Selva Drive and Evergreen Drive. Moved misplaced markers for St. Catherine of Alexandria Catholic School and St. Catherine of Alexandria Catholic Church and corrected titles for same. Removed nonexistent street originally called "Jaspar Ct."; this is actually a private drive and service access road at the end of West Dunne Ave.

I've tried moving the Morgan Hill Museum to its current physical location on Monterey Street a couple of times, but the database has so far refused to accept the update. The building was physically moved from its location on West Main Street between Peak Avenue and Dewitt Avenue in 2006, in preparation for the construction of the new Morgan Hill Library in the Morgan Hill Civic Center block. Maybe the problem has something to do with the data associated with this feature, or maybe it's just database lag. I'll have to check back tomorrow to see if the update finally was accepted.