Hi Robert, my search range it's between 5 and 100km, so I was thinking to use a small grid and retrive the 9 cells around the point by using the IN operator. Then, I have seen on the documentation that using the IN operator actually split the original query in N subqueries (9 in my case) so I guess I need to run some performance test.
Cesare On 15 January 2011 07:52, Robert Kluin <robert.kl...@gmail.com> wrote: > Hi Cesare, > The underlying concept to your idea is basically the same; most > techniques use an approach based on the idea that if you store a > "lower-resolution" point, you can figure out what else is close since > they might also be at that lower-res point. Your idea is basically a > version of the bounding-boxes approach. > http://code.google.com/appengine/articles/geosearch.html > > If you do not want to use one of the existing solutions, make sure > you consider cases when your original point is very close to the edge > of your box. If you don't you'll miss some close results. > > > Robert > > > > > > On Tue, Jan 11, 2011 at 18:01, Cesare Montresor > <cesare.montre...@gmail.com> wrote: >> Hi, >> my name it's Cesare, I'm new to GAE (3 days) and this group as well, I >> would like to take this opportunity to say hello to everybody :) >> >> I guess that many many peaople had the same ploblem of mine, because >> of the limitations of GQL about using an inequality operator on more >> than 1 property and so the problem of retriving location within a >> given range. >> I barelly evaluated GeoModel (http://code.google.com/p/geomodel/) but >> seams to me that it's big and anyway doesn't really solve the problem >> of filtering the data on GQL end only. >> >> I would like to have an optionion from you guys about this very simple >> idea that I go this morning under the shower ... :) >> The idea it's basically to "round" latitude and longitude to integer >> (for to float few decimals) and use this value as "tag" so in this way >> i will be able to pull the data from the datastore just by using = or >> IN operator to retrive the locations in a specific area. it's an hash >> table but not with unique hash, on 2 different fields. >> >> In this way the dataset in not the smallest as possible, you may need >> to refine the seach in the code, but should be small enough. >> >> That's all, >> I will be happy to get ideas, improvments, suggestion and criticism as >> well :) >> >> >> Thanks, >> Cesare Montresor >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Google App Engine" group. >> To post to this group, send email to google-appengine@googlegroups.com. >> To unsubscribe from this group, send email to >> google-appengine+unsubscr...@googlegroups.com. >> For more options, visit this group at >> http://groups.google.com/group/google-appengine?hl=en. >> >> > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To post to this group, send email to google-appengine@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
