[postgis-devel] Float vs Double Box

[Brian Hamlin]

in an age of GPUs, I view the memory savings of float vs double to be  
very minor
yes I understand the counter-point.. but really!

$0.00002   -Brian


On Nov 10, 2011, at 10:07 PM, Sandro Santilli wrote:

> On Thu, Nov 10, 2011 at 04:05:03PM +0000, Mark Cave-Ayland wrote:
>> On 09/11/11 20:09, Nicklas Avén wrote:
>>
>>> Another aspect of double vs float is that the float boxes might give
>>> wrong ordering from knn-gist.
>>>
>>> In other cases we can round the float box up to a slightly bigger  
>>> box,
>>> but in the ordering case that will not help.
>>>
>>> That is why we get different answer from native Postgresql knn and
>>> PostGIS as I discussed the other week, because Postgresql is not  
>>> using
>>> the bbox but the point itself. I'm I right or have I misunderstood?
>>
>> Yes indeed, this was the reason I was suggesting that we should be
>> using doubles for everything - coordinates, internal BBOXes and the
>> index. Otherwise we find ourselves in situations where queries can
>> return different results depending upon whether either a sequential
>> scan or an index scan is used, or whether the geometry has an
>> internal BBOX or not :(
>
> Or floats for every box, right ?
> That should be pretty consistent: box operations are floats,
> shape operations are double.
>
> --strk;
>
>   ()   Free GIS & Flash consultant/developer
>   /\   http://strk.keybit.net/services.html
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