Re: A new proof of the superiority of set oriented approaches: numerical/time serie linear interpolation

From: Tonkuma <tonkuma_at_jp.ibm.com>
Date: 29 Apr 2007 11:24:00 -0700
Message-ID: <1177871040.305760.147680_at_h2g2000hsg.googlegroups.com>

On Apr 29, 7:04 pm, Cimode <cim..._at_hotmail.com> wrote:
> ID Distance ArrivalTime
> 24 0.289 2000-01-01 06:29:00.000
> 25 0.193 NULL --> 1st value to be interpolated
> 26 0.299 NULL --> 2nd value to be interpolated
> 27 0.131 NULL --> 3rd value to be interpolated
> 28 0.444 NULL --> 4th value to be interpolated
> 29 0.16 NULL --> 5th value to be interpolated
> 30 0.665 NULL --> 6th value to be interpolated
> 31 0.186 2000-01-01 06:33:00.000
>
> As a result, I obtained the following interpolation...
>
> ID Distance ArrivalTime
> 24 0.289 2000-01-01 06:29:00.000
> 25 0.193 2000-01-01 06:29:24.000
> 26 0.299 2000-01-01 06:29:37.000
> 27 0.131 2000-01-01 06:29:16.000
> 28 0.444 2000-01-01 06:29:56.000
> 29 0.160 2000-01-01 06:29:20.000
> 30 0.665 2000-01-01 06:30:24.000
> 31 0.186 2000-01-01 06:33:00.000
>

I couldn't understand well the meaning of ID(pehaps station ID) and Distance.
Looking your result rows with NULL ArrivalTime, ID is sequenced by Distance.
But, rows with NOT NULL ArrivalTime seems that station is sequenced by ID.
That means lowest ID 24 is start station and largest ID 31 is destination station.
But, distance of 24 is not 0, it is 0.289. So, my question is Distant of ID 24 is from where? And Distance of ID 31(0.186) is from where? I think my question would be more clear, if result rows sequenced by distance.
 Like this:

ID      Distance  ArrivalTime
27      0.131      2000-01-01 06:29:16.000
29      0.160      2000-01-01 06:29:20.000


> 31      0.186      2000-01-01 06:33:00.000

25      0.193      2000-01-01 06:29:24.000


> 24      0.289      2000-01-01 06:29:00.000

26      0.299      2000-01-01 06:29:37.000
28      0.444      2000-01-01 06:29:56.000
30      0.665      2000-01-01 06:30:24.000

Except ID 24 and ID 31(These ArrivalTime were NOT NULL), ArrivalTime seems prportional to Distance beween ArrivalTime of ID 24 and ID 31.

One reason I asked this is that if ArrivalTime of some station(s) between ID 24 and ID 31 is NOT NULL, what is the distance of that station?.
For example:
> ID Distance ArrivalTime
> 24 0.289 2000-01-01 06:29:00.000
> 25 0.193 NULL --> 1st value to be interpolated
> 26 0.299 NULL --> 2nd value to be interpolated
> 27 0.131 NULL --> 3rd value to be interpolated
> 28 0.444 NOT NULL --> value is already known
> 29 0.160 NULL --> 4th value to be interpolated
> 30 0.665 NULL --> 5th value to be interpolated
> 31 0.186 2000-01-01 06:33:00.000

And more important question is how to calculate middle ArrivalTime which is NULL. Received on Sun Apr 29 2007 - 20:24:00 CEST