David,
as far as I know, pretty much only the filter GXs allow multi-record access
(i.e. reading on one more adjacent records up/down a data column), but there
I think there is no ready access to the n+1 or n-1 record while doing math
on the nth record unless you go in via a specialised non-routine GX or
script. The nth difference filter is a case in point, where the 1st diff.
looks at only the n & n-1 records
Have you tried Excel ?
As I'm no expert in GX scripting, ask Geosoft.
Nick.
> -----Original Message-----
> From: David Humphrey [SMTP:[EMAIL PROTECTED]]
> Sent: Thursday, July 15, 1999 1:15 PM
> To: '[EMAIL PROTECTED]'
> Subject: RE: [geonet]: Calculating speed from (x,y,t) points
>
> I agree complete, but within Oasis montaj, is there there a function that
> will give me the time difference? Everything I read deals with channel
> oriented math where one uses only channel values from a record to compute
> a
> new channel for that record, but nowhere do I see how to access a channel
> on
> record n-1 when computing a new channel on record n. Am I missing
> something
> here?
>
> David L. Humphrey
> Manager, Software Development
> Bell Geospace, Inc
>
>
> -----Original Message-----
> From: Gant, Nicholas (NGAN) [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, July 15, 1999 2:46 PM
> To: '[EMAIL PROTECTED]'
> Subject: RE: [geonet]: Calculating speed from (x,y,t)
> points
>
> David,
>
> take the 1st. difference of the of the time records and
> divide it into the
> corresponding distances (distance/time = speed).
>
> Nick Gant,
> Coordinator, G&M.
> Chevron Overseas Pet. Inc.,
> San Ramon, CA.
> Ph: (925) 842 3691, FAX (925) 824 0062.
> e-mail: [EMAIL PROTECTED]
>
>
> > -----Original Message-----
> > From: David Humphrey [SMTP:[EMAIL PROTECTED]]
> > Sent: Thursday, July 15, 1999 12:42 PM
> > To: '[EMAIL PROTECTED]'
> > Subject: [geonet]: Calculating speed from (x,y,t)
> points
> >
> > I have a database containing (x,y) coordinates and time
> for each point. I
> > want to calculate speed s at each point according to the
> formula:
> >
> > S2 = (d2-d1)/(t2-t1)
> >
> > Where d1 and d2 are the distance along the line for
> successive points. I
> > see a GX that does the distance calculation, but don't see
> how to get the
> > time difference. The problem is using values from
> different records in a
> > .gdb.
> >
> > I know I can write a GX that does this, but would like to
> use existing
> > Oasis
> > montaj machinery, if possible. Does anyone know a better
> way?
> >
> > Thanks in advance.
> >
> > David L. Humphrey
> > Manager, Software Development
> > Bell Geospace, Inc
> >
> > _______________________________________________________
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