Re: [OSM-talk] Maxheight changes
2010/1/1 Ben Laenen benlae...@gmail.com If something over that height isn't allowed, then it doesn't matter how many zeros you add. If your car is 2.1 meters high, you're not allowed, period (...but with the devices used for measuring). even legally there will be some tolerance, if a sign is saying maxheight 2, you will not have any problems even if your vehicle is 2.01 metres high, nor will a possible fine depend on the quality of measuring device used by the police to get to an infinite number of trailing zeros before a 1. Still I agree that 2.0 is different to 2 as ít indicates probably the precision of the number. cheers, Martin ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
[OSM-talk] Maxheight changes
I've just noticed that AlexanderF is changing all the maxheight=2.0 to maxheight=2. In fact he's changing anything ending with 0 after the decimal point to drop the zero. This is not good, he is lowering the accuracy of the tag, which is why they are displayed with a trailing zero on signs. I have sent a message to him, but no answer yet. Does anyone know him so they can ask him to stop and revert his changes? Cheers, Chris ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maxheight changes
Chris Hill wrote: I've just noticed that AlexanderF is changing all the maxheight=2.0 to maxheight=2. In fact he's changing anything ending with 0 after the decimal point to drop the zero. This is not good, he is lowering the accuracy of the tag, which is why they are displayed with a trailing zero on signs. I have sent a message to him, but no answer yet. Does anyone know him so they can ask him to stop and revert his changes? I don't why he feels the need to do this, it seems a pointless task, but why do you think it reduces accuracy to remove trailing zeros? 2m =2.0m Dave F. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maxheight changes
2010/1/1 Dave F. dave...@madasafish.com: Chris Hill wrote: I've just noticed that AlexanderF is changing all the maxheight=2.0 to maxheight=2. In fact he's changing anything ending with 0 after the decimal point to drop the zero. This is not good, he is lowering the accuracy of the tag, which is why they are displayed with a trailing zero on signs. I have sent a message to him, but no answer yet. Does anyone know him so they can ask him to stop and revert his changes? I don't why he feels the need to do this, it seems a pointless task, but why do you think it reduces accuracy to remove trailing zeros? 2m =2.0m Yes, but it's a means of expressing precision, 2m could mean 2.4 or 1.5 if you round. Where as 2.0m means 1.95 to 2.04... ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maxheight changes
Dave F. wrote: I don't why he feels the need to do this, it seems a pointless task, but why do you think it reduces accuracy to remove trailing zeros? 2m =2.0m Mathematically, you may be right. But having 2.0 actually means that it is 2.0 m with +- 0.1 m accuracy. Putting it as 2 means it's 2 meters +- 1 m. -- Lennard ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maxheight changes
On Sat, Jan 2, 2010 at 12:14 AM, Dave F. dave...@madasafish.com wrote: I don't why he feels the need to do this, it seems a pointless task, but why do you think it reduces accuracy to remove trailing zeros? 2m =2.0m It reduces *indication of accuracy*. There's a difference between I measured that bridge, and it's 2 metres high and I measured that bridge, and it's 2.000 metres high. If the signposted maximum height under the bridge is 2.0m, it should be recorded as 2.0, not as 2. Especially since for such things, 10 centimetres here or there is pretty significant. Steve ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maxheight changes
2010/1/1 Steve Bennett stevag...@gmail.com: On Sat, Jan 2, 2010 at 12:14 AM, Dave F. dave...@madasafish.com wrote: I don't why he feels the need to do this, it seems a pointless task, but why do you think it reduces accuracy to remove trailing zeros? 2m =2.0m It reduces *indication of accuracy*. There's a difference between I measured that bridge, and it's 2 metres high and I measured that bridge, and it's 2.000 metres high. If the signposted maximum height under the bridge is 2.0m, it should be recorded as 2.0, not as 2. Especially since for such things, 10 centimetres here or there is pretty significant. Not to mention most signs on bridges indicate 2.0m not 2m. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maxheight changes
Steve Bennett wrote: On Sat, Jan 2, 2010 at 12:14 AM, Dave F. dave...@madasafish.com wrote: I don't why he feels the need to do this, it seems a pointless task, but why do you think it reduces accuracy to remove trailing zeros? 2m =2.0m It reduces *indication of accuracy*. There's a difference between I measured that bridge, and it's 2 metres high and I measured that bridge, and it's 2.000 metres high. If the signposted maximum height under the bridge is 2.0m, it should be recorded as 2.0, not as 2. Especially since for such things, 10 centimetres here or there is pretty significant. While I agree that we should put in the tag whatever there is on the sign, maxheight=2 has absolutely no different meaning than maxheight=2.0. If something over that height isn't allowed, then it doesn't matter how many zeros you add. If your car is 2.1 meters high, you're not allowed, period (albeit chances of getting caught are very slim, as no ruler could measure it that accurately anyway, but that has nothing to do with the number of trailing zeros on the sign, but with the devices used for measuring). Telling maxheight=2 doesn't mean that cars between 1.5m and 2m have to watch out because they might not fit under the bridge. But on measured numbers, those trailing zeros are important indeed. That bridge is 2 meters high, or that bridge is 2.00 meters high: these sentences do mean different things. I'd be much more confident driving my 1.90m high car under that second bridge. So, numbers on signs about restrictions (maximum speed, maximum height, maximum length, maximum weight...): trailing zeros have no value, as those numbers are exact. Numbers about measurements (elevation, height of a bridge, road width): trailing zeros do have value. Greetings Ben ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maxheight changes
On Fri, Jan 1, 2010 at 4:39 PM, Ben Laenen benlae...@gmail.com wrote: Steve Bennett wrote: On Sat, Jan 2, 2010 at 12:14 AM, Dave F. dave...@madasafish.com wrote: I don't why he feels the need to do this, it seems a pointless task, but why do you think it reduces accuracy to remove trailing zeros? 2m =2.0m It reduces *indication of accuracy*. There's a difference between I measured that bridge, and it's 2 metres high and I measured that bridge, and it's 2.000 metres high. If the signposted maximum height under the bridge is 2.0m, it should be recorded as 2.0, not as 2. Especially since for such things, 10 centimetres here or there is pretty significant. While I agree that we should put in the tag whatever there is on the sign, maxheight=2 has absolutely no different meaning than maxheight=2.0. If something over that height isn't allowed, then it doesn't matter how many zeros you add. If your car is 2.1 meters high, you're not allowed, period (albeit chances of getting caught are very slim, as no ruler could measure it that accurately anyway, but that has nothing to do with the number of trailing zeros on the sign, but with the devices used for measuring). Telling maxheight=2 doesn't mean that cars between 1.5m and 2m have to watch out because they might not fit under the bridge. But on measured numbers, those trailing zeros are important indeed. That bridge is 2 meters high, or that bridge is 2.00 meters high: these sentences do mean different things. I'd be much more confident driving my 1.90m high car under that second bridge. So, numbers on signs about restrictions (maximum speed, maximum height, maximum length, maximum weight...): trailing zeros have no value, as those numbers are exact. Numbers about measurements (elevation, height of a bridge, road width): trailing zeros do have value. Greetings Ben I think some documentation on the wiki says something about use what's on the sign, so if the sign says 2.0 than the tag should be 2.0. Same also if the sign says 6ft9in than it should be tagged such. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maxheight changes
On Sat, Jan 2, 2010 at 2:39 AM, Ben Laenen benlae...@gmail.com wrote: So, numbers on signs about restrictions (maximum speed, maximum height, maximum length, maximum weight...): trailing zeros have no value, as those numbers are exact. Not necessarily. Perhaps the number on the sign came from a measurement? E.g. Maximum Clearance: 2.0 Perhaps this is a case of ambiguity between whether the number refers to a restriction or to physical clearance. I suspect this ambiguity is quite common. Numbers about measurements (elevation, height of a bridge, road width): trailing zeros do have value. As I said, the number on the sign may have come from a measurement. I think the trailing zeros should be retained unless there is a specific reason to remove them. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maxheight changes
2010/1/2 Roy Wallace waldo000...@gmail.com: On Sat, Jan 2, 2010 at 2:39 AM, Ben Laenen benlae...@gmail.com wrote: So, numbers on signs about restrictions (maximum speed, maximum height, maximum length, maximum weight...): trailing zeros have no value, as those numbers are exact. Not necessarily. Perhaps the number on the sign came from a measurement? E.g. Maximum Clearance: 2.0 Perhaps this is a case of ambiguity between whether the number refers to a restriction or to physical clearance. I suspect this ambiguity is quite common. This came up some time ago, there was a thread about maxheight and maxheight:physical and I think the majority of the time signs indicate the legal clearance. You can see this clearly if you find a bridge that is sloped, like one near here has 5.0m on both side even though you could clearly have half a metre more on the higher side. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
