On Apr 24, 11:45 am, Wally <[email protected]> wrote: > The zoom level algorithm can be changed. A less aggressive > sequence of zoom levels may improve performance but hurt > appearance at very deep zoom levels. It requires some > experimenting.
We must have simultaneously cross-posted. As I stated in my other post, perhaps there are some parameters that can be fiddled with that can improve the performance of Packer. I don't know, since I haven't seen a complete description of how it works. My intuition tells me, though, that any single pass algorithm is unlikely to perform as well as DP. In fact, my first attempt at polyline encoding generalized a simple, single pass point reduction algorithm. I was dis-satisfied with the results so I wrote the current version. > > (2) What's this Lat/Lng bias? The API expects Lat/Lngs. > > A degree of Latitude is not equal to a degree of Longitude > except at the equator. The API must project Lat/Lon > coordinates into pixels in order to render the poly. I haven't found this to be an issue, at least not with the maps that I generate. I could imagine that it might turn into an issue for some polylines that vary greatly in latitude, but this ultimately has little to do with DP/encoding strings. John and Marcelo's encoder gets around this by simply using actual distance on the ground between two points in the DP algorithm. I think it might be simpler to first project to Mercator, perform the encoding, and then project back. Regardless, I didn't find it to be of great importance when first writing the encoder and I still don't. By the way, I find your work to be interesting and I certainly don't mean to demean it. I just think that some of your statements about polyline encoding seem to be a little off. I also haven't really seen an adequate description of Packer in terms of how it produces levels strings so it's a little hard to render a judgment. Mark --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google Maps API" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/Google-Maps-API?hl=en -~----------~----~----~----~------~----~------~--~---
