It is possible the coordinate conversion was not very accurate but the source data was. I had some problems before converting Lambert coordinates and got about the same deviations.
Regards, Ben On Fri, Apr 22, 2011 at 9:59 PM, Linus Able <[email protected]> wrote: > Hello everybody, Hello Pol, > > i should want to question the accuracy of the data. I have seen (before Pol > deleted the data) one of the antenna points on the (openstreetmap) > Grand-Place de Mons, in JOSM, with Bing aerial as background. The point is > café Le Central, at the corner of Grand Place with rue de Nimy. I suppose > the Antenna is on the roof, but it appeared a few meters on the Grand Place, > with a difference of about 5-10m compare to the Bing images. > > What is wrong (or imprecise) : antenna coordinates or Bing position ? > > In order to investigate Bing positionning around Mons, I checked against a > geodetic > point from ign/ngi (www.ngi.be), using Fiche Planimétrique45D06C1, with a > survey point at position N 50.47149281234526 E 4.028218331187543 (Obourg). > It seems that the error is less than 1-2 meters. > > My naive first conclusion is that the accuracy of the antenna positions > could be quite poor, specially in dense area (towns or cities). This could > result to absurd situations like antenna on streets. > > Maybe it could be interesting to use a script to analyse distance of > antenna (from the data files) with nearest streets ? or another standard > procedure ? > > Regards, > > Linusable > > Le 22/04/11 16:33, Pol a écrit : > > I deleted them this morning and as long as the situation is not clear. > > -*φol d.*- > > > > On Fri, Apr 22, 2011 at 10:22, Gerard Vanderveken <[email protected]> wrote: > >> I was looking up some on the map, but it seems that tower:type = >> communications is not rendered anymore??? >> I tought they were before, altough only in Osmarender, cfr VRT radio and >> tv towers in Overijse - Wavre. >> >> I see some have a name, but I'm affraid that it won't add much, but >> instead duplicating and cluthering the rendering and names of the current >> places (buildings like churches etc) >> http://www.openstreetmap.org/browse/changeset/7911333 >> Some has also very generic names eg. watertoren, kerk, etc >> >> There is a Wiki about GSM in the Belgian project >> >> http://wiki.openstreetmap.org/wiki/WikiProject_Belgium/Mapping_resources#GSM.2FUMTS_antenna_sites >> >> Should the points not to be deleted, until the status about their use >> becomes clear?? >> For the moment it is obvious that it is forbidden data. >> >> Regards, >> Gerard. >> >> Pol wrote: >> >> Hello, >> >> I contacted them this morning and they asked me to write down a mail >> explaining the request, why, etc etc etc. >> That's what I did. If you want a copy of the mail (in french), just >> contact me in private. >> >> They told me that they will forward the mail to their law departement >> and I should expect an answer next week. >> >> Let's cross our fingers ! ;) I'll keep you updated of the situation ! >> >> By the way, I'll be at the hackdemocracy this Thursday, April 28, 2011: >> http://www.meetup.com/HackDemocracy/events/17010026/ >> >> Have a nice day all. >> >> -*φol d.*- >> >> >> On Thu, Apr 21, 2011 at 22:14, Pol <[email protected]> wrote: >> >>> Hello, >>> >>> Someone forwarded me the mail from Lennard talking about the revert or >>> not of my commit. >>> I wasn't aware of the existence of that mailing list until now. >>> >>> Let me explain to all of you how it all began... >>> >>> One year ago I was looking, for personal purpose, the coordinates of >>> each cell phones antennas in Belgium. >>> >>> The first site I found was: http://www.antennes-gsm.be/ >>> But that one seems to be old and no more maintained. >>> >>> Then I found the one of IBPT: http://www.sites.ibpt.be/ >>> >>> The one you are currently seeing at this address is the new version. >>> When I first found it, they were using an old version. >>> >>> By doing some searches, I found a huge security hole in it. >>> I was unemployed at that time and I decided to make an exploit. >>> The exploit was simple, using HTML and JavaScript, I could manipulate >>> their databases by sending custom queries. >>> I'm not a kid and I'm someone who destroy someone else's work, so I >>> contacted them and explained the problem. >>> The reaction was fast, some days later I was in their offices with my >>> laptop, showing them the problem and the possible solutions. >>> I also made a new local proof of concept that it could be done in a nicer >>> and cleaner way. >>> Unfortunately, they were really kind and say thanks but we do not rely on >>> our team to do the map, we rely on another company and we cannot break the >>> current contract with them. >>> Before leaving, I asked to the head of security if it was possible to get >>> a dump of the antennas coordinates in a more easy way to put it on >>> OpenStreetMap and he said that it couldn't be done: "Imaginez ce que >>> pourrait faire qqun de mal intentionné s'il trouve ces données!" which >>> means: "Imagine what could do someone malicious if they finds these datas!". >>> Which is completely a non sense because those datas can be retrieved from >>> THEIR online website. >>> I said him that ! Someone could spot by himself all the antennas and put >>> them on OpenStreetMap. He didn't reply to that one. >>> So, I leaved, quite sad. >>> >>> Some month later, the current new system was in place and the security >>> hole vanished, problem solved. >>> >>> With the new system, it's even easier to get their datas. >>> I decided to save in a file all the data I could get from their map in a >>> file and submit it to OpenStreetMap. >>> >>> That's the end of the story. >>> >>> It's up to you now to decide if you want to remove them or not. >>> If you have questions, I'll reply to them on that mailing list. >>> >>> Nice evening all. >>> >>> -*φol d.*- >>> >> >> ------------------------------ >> >> _______________________________________________ >> Talk-be mailing list >> [email protected] >> http://lists.openstreetmap.org/listinfo/talk-be >> >> >> _______________________________________________ >> Talk-be mailing list >> [email protected] >> http://lists.openstreetmap.org/listinfo/talk-be >> >> > > > _______________________________________________ > Talk-be mailing list > [email protected] > http://lists.openstreetmap.org/listinfo/talk-be > > > _______________________________________________ > Talk-be mailing list > [email protected] > http://lists.openstreetmap.org/listinfo/talk-be > >
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