[Baypiggies] Hi all -can anyone convert this code to python---many thanks

Pavel Pergamenshchik ppergame at cisco.com
Thu Dec 14 19:41:27 CET 2006


I'm guessing the software in question is sold
through http://store.esri.com/esri/ at prices of several hundred
dollars.
Sharon appears to be significantly confused.

On Thu, 14 Dec 2006 10:22:47 -0800
"Russell Whitaker" <whitaker at google.com> wrote:

> At first approximation, this sounds like a request for free
consulting, or a
> "do my homework for me" request.  Am I mistaken?  Or is this
associated with
> a known, collaborative opensource project on sourceforge?
> 
> Curious,
> Russell
> 
> On 12/14/06, Sharon Kazemi <sharonk at gisc.berkeley.edu> wrote:
> > Hi all,
> >
> > have below code that needs to be recoded into Python for use in ESRI
ArcGIS
> > software.
> > I would greatly appreciate any assistance.
> > Thanks
> > Sheri
> >
> > /*  The Inner Loop of the Douglas-Peucker line generalization
> > algorithm is the process of finding, for a section of a polyline,
> > the vertex that is furthest from the line segment joining the
> > two endpoints.  The method coded below in C (or C++) is the most
> > efficient, in terms of operation counts, that I have seen.  */
> >  /*  _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
*/
> >
> > long FurthestFromSegment ( /* Return index of furthest point.  */
> >     long    startindex,    /* Index of start vertex in arrays.  */
> >     long    endindex,      /* Index of end vertex in arrays.  */
> >     double *x         ,    /* Array, abscissae of polyline vertices.
*/
> >     double *y         ,    /* Array, ordinates of polyline vertices.
*/
> >     double *distMaxSquare  /* Return square of maximum distance.  */
> >                          )
> >   /*
> >    This function, given a section of a polyline in arrays,
> >     will return the index of the intermediate node that is furthest
> >     from the segment joining the two endpoints of the section,
> >     and the square of the distance from the segment.
> >
> >    If no intermediate point exists, then the returned index will
> >     be the index of the start vertex and the returned distance
> >     squared will be -1.0 .  Caution:  Do not calculate the square
> >     root of this returned value without ruling out the possibility
> >     that it may have defaulted to -1.0 .  In a normal
> >     Douglas-Peucker application, you should never have to calculate
> >     the square root of this output value, and you should never
> >     need to invoke this function without intermediate points.
> >   */
> > {
> >       /*
> >        The variable names below assume we find
> >          the distance of point "A" from segment "BC" .
> >       */
> >     long index, outindex ;
> >     double distSquare, bcSquare ;
> >     double cx, cy, bx, by, ax, ay ;
> >     double bcx, bcy, bax, bay, cax, cay ;
> >
> >     *distMaxSquare  =  -1.0 ;
> >     if ( endindex  <  startindex + 2 )    return startindex ;
> >     outindex  =  startindex ;
> >     bx  =  x[startindex] ;
> >     by  =  y[startindex] ;
> >     cx  =  x[endindex] ;
> >     cy  =  y[endindex] ;
> >       /* Find vector BC and the Square of its length.  */
> >     bcx  =  cx - bx ;
> >     bcy  =  cy - by ;
> >     bcSquare  =  bcx * bcx  +  bcy * bcy ;
> >       /* The inner loop:  */
> >     for ( index = startindex + 1 ; index < endindex ; index++ )
> >     {
> >           /* Find vector BA .  */
> >         ax  =  x[index] ;
> >         ay  =  y[index] ;
> >         bax  =  ax - bx ;
> >         bay  =  ay - by ;
> >           /* Do scalar product and check sign.  */
> >         if ( bcx * bax  +  bcy * bay    <=    0.0 )
> >         {
> >               /* Closest point on segment is B; */
> >               /*   find its distance (squared) from A .  */
> >             distSquare   =   bax * bax  +  bay * bay ;
> >         }
> >         else
> >         {
> >               /* Find vector CA .  */
> >             cax  =  ax - cx ;
> >             cay  =  ay - cy ;
> >               /* Do scalar product and check sign.  */
> >             if ( bcx * cax  +  bcy * cay    >=    0.0 )
> >             {
> >                   /* Closest point on segment is C; */
> >                   /*   find its distance (squared) from A .  */
> >                 distSquare   =   cax * cax  +  cay * cay ;
> >             }
> >             else
> >             {
> >                   /* Closest point on segment is between B and C; */
> >                   /*    Use perpendicular distance formula.  */
> >                 distSquare    =    cax * bay  -  cay * bax ;
> >                 distSquare    =    distSquare * distSquare /
bcSquare ;
> >                       /* Note that if bcSquare be zero, the first
> >                           of the three branches will be selected,
> >                           so division by zero will not occur here.
*/
> >             }
> >         }
> >
> >         if ( distSquare > *distMaxSquare )
> >         {
> >             outindex  =  index ;
> >             *distMaxSquare  =  distSquare ;
> >         }
> >     }
> >       /*
> >          Note that in the inner loop above, if we follow
> >          the most common path where the perpendicular
> >          distance is the one to calculate, then for each
> >          intermediate vertex the float operation count is
> >          1 divide, 7 multiplies, 5 subtracts, 1 add, and 2 compares.
> >       */
> >
> >     return outindex ;
> > }
> >
> > Sharon Kazemi
> > Visiting Scholar/GIS Analyst
> > Geographic Information Science Center
> > 412 Wurster Hall
> > University of California Berkeley
> > Berkeley, CA 94720-1820
> > Phone: +1-510-642-2812
> > Fax: +1-510-643-3412
> > Email: sharonk at gisc.berkeley.edu
> > http://www.gisc.berkeley.edu/
> >
> >
> >
> > -----Original Message-----
> > From: baypiggies-bounces at python.org
> > [mailto:baypiggies-bounces at python.org]On Behalf Of
> > baypiggies-request at python.org
> > Sent: Thursday, December 14, 2006 3:00 AM
> > To: baypiggies at python.org
> > Subject: Baypiggies Digest, Vol 14, Issue 16
> >
> >
> > Send Baypiggies mailing list submissions to
> >         baypiggies at python.org
> >
> > To subscribe or unsubscribe via the World Wide Web, visit
> >         http://mail.python.org/mailman/listinfo/baypiggies
> > or, via email, send a message with subject or body 'help' to
> >         baypiggies-request at python.org
> >
> > You can reach the person managing the list at
> >         baypiggies-owner at python.org
> >
> > When replying, please edit your Subject line so it is more specific
> > than "Re: Contents of Baypiggies digest..."
> >
> >
> > Today's Topics:
> >
> >    1. Re:  Dec. 14 Meeting "Programming Productivity: What     
Really
> >       Matters?" (Anna Ravenscroft)
> >    2. Re:  Dec. 14 Meeting "Programming Productivity: What     
Really
> >       Matters?" (Shannon -jj Behrens)
> >    3. Re:  Dec. 14 Meeting "Programming Productivity: What Really
> >       Matters?" (Dennis Reinhardt)
> >    4. Re:  Dec. 14 Meeting "Programming Productivity: What     
Really
> >       Matters?" (Anna Ravenscroft)
> >    5. Re:  Dec. 14 Meeting "Programming Productivity: What     
Really
> >       Matters?" (Marilyn Davis)
> >    6. Re:  Dec. 14 Meeting "Programming Productivity: What     
Really
> >       Matters?" (Anna Ravenscroft)
> >    7. Re:  Dec. 14 Meeting "Programming Productivity: What     
Really
> >       Matters?" (Alex Martelli)
> >
> >
> >
----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Wed, 13 Dec 2006 17:22:03 -0800
> > From: "Anna Ravenscroft" <annaraven at gmail.com>
> > Subject: Re: [Baypiggies] Dec. 14 Meeting "Programming Productivity:
> >         What    Really Matters?"
> > To: "Mike Cheponis" <mac at wireless.com>
> > Cc: Python <baypiggies at python.org>
> > Message-ID:
> >        
<cb361a610612131722v7c6fef90ha4504a604b9b5246 at mail.gmail.com>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> > On 12/13/06, Mike Cheponis <mac at wireless.com> wrote:
> > > "Social Time" is really just "Random Mapping".
> > >
> > > So, if nobody stands up during "Mapping" you get all "Social
Time".  Also,
> > those that don't "map" are, by default, in the "Social" mapping...
> > >
> > > Don't worry, the meetings aren't nearly as formal as our
discussions
> > _about_ the meetings are(!).
> > >
> > > -Mike
> >
> > I've been to the meetings. Social TIme != mapping.
> >
> > I don't have time or energy to wait for the formal "mapping" to get
> > over with before I can socialize with people. I have a final
tomorrow
> > and expect to be pretty exhausted and wanting to go to bed early. I
> > was looking forward to some generic, informal socializing.
> >
> > OR can we have some freeform socializing BEFORE the official part of
> > the meeting - that way those who want (and have the energy) to do
the
> > mapping can stay for that?
> >
> > Anna
> >
> >
> > ------------------------------
> >
> > Message: 2
> > Date: Wed, 13 Dec 2006 18:09:35 -0800
> > From: "Shannon -jj Behrens" <jjinux at gmail.com>
> > Subject: Re: [Baypiggies] Dec. 14 Meeting "Programming Productivity:
> >         What    Really Matters?"
> > To: "Anna Ravenscroft" <annaraven at gmail.com>
> > Cc: Python <baypiggies at python.org>, Mike Cheponis <mac at wireless.com>
> > Message-ID:
> >        
<c41f67b90612131809q37612254i1007ffe3e5fb7667 at mail.gmail.com>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> > On 12/13/06, Anna Ravenscroft <annaraven at gmail.com> wrote:
> > > On 12/13/06, Mike Cheponis <mac at wireless.com> wrote:
> > > > "Social Time" is really just "Random Mapping".
> > > >
> > > > So, if nobody stands up during "Mapping" you get all "Social
Time".
> > Also, those that don't "map" are, by default, in the "Social"
mapping...
> > > >
> > > > Don't worry, the meetings aren't nearly as formal as our
discussions
> > _about_ the meetings are(!).
> > > >
> > > > -Mike
> > >
> > > I've been to the meetings. Social TIme != mapping.
> > >
> > > I don't have time or energy to wait for the formal "mapping" to
get
> > > over with before I can socialize with people. I have a final
tomorrow
> > > and expect to be pretty exhausted and wanting to go to bed early.
I
> > > was looking forward to some generic, informal socializing.
> > >
> > > OR can we have some freeform socializing BEFORE the official part
of
> > > the meeting - that way those who want (and have the energy) to do
the
> > > mapping can stay for that?
> >
> > It sounds like we have a pretty vocal contingent of people who want
30
> > minutes of informal socializing followed by an hour for the actual
> > talk.  That's fine by me.
> >
> > -jj
> >
> > --
> > http://jjinux.blogspot.com/
> >
> >
> > ------------------------------
> >
> > Message: 3
> > Date: Wed, 13 Dec 2006 18:17:51 -0800
> > From: Dennis Reinhardt <DennisR at dair.com>
> > Subject: Re: [Baypiggies] Dec. 14 Meeting "Programming Productivity:
> >         What Really Matters?"
> > To: Python <baypiggies at python.org>
> > Message-ID: <5.1.0.14.0.20061213173953.023a51d0 at localhost>
> > Content-Type: text/plain; charset="us-ascii"; format=flowed
> >
> > At 05:22 PM 12/13/2006, Anna Ravenscroft wrote:
> >
> > >OR can we have some freeform socializing BEFORE the official part
of
> > >the meeting -
> >
> > Anna,
> >
> > I have regularly attended the pre-dinner meetings Brian has
organized (at
> > least the ones at IronPort).  They may well be the social time you
are
> > looking for and in the time frame you ask for.
> >
> > If one looks at the agenda template we have had this year, it looks
like:
> >
> >          7:00 - 7:30 unstructured pre-meeting
> >          7:30 - 9:00 meeting program
> >
> > Nothing has prevented people from socializing in the 7:00 - 7:30
> > pre-meeting time frame.  By my observation, not that much
socialization
> > gets done then.  Whatever limiters there are in socializing in the
7:00 to
> > 7:30 time frame are likely to affect tomorrow's meeting as well. 
Suppose
> > we revise the schedule to read
> >
> >          7:00 - x:yz social
> >          x:yz - 9:00 program
> >
> > I don't think moving the 7:00 earlier is that easy without checking
the
> > room schedule or someone from Google taking responsibility for being
> > there.  Could happen but the fact is that we already have an time
preceding
> > every meeting where completely unstructured socialization is
possible.
> >
> > Suppose we set x:yz to 7:40, allowing JJ's presentation to take the
entire
> > 80 minutes.  IMO, we have run that experiment as well and it is
called
> > starting the meeting 10 minutes late.  I have not seen the demand
for that.
> >
> > The major alternative here is set x:yz to 9:00 and shut down JJ's
talk
> > entirely.  My sense is that JJ has a great talk planned and while
meet and
> > greet was preferred to no meeting at all, JJ's unabridged talk and
> > free-for-all discussion (i.e. what passes for socialization for some
of us)
> > is a preferred use of the time available.
> >
> > If you have not attended the pre-meeting dinners, I can recommend
them as a
> > good way to socialize.
> >
> > Dennis
> >
> >
> >   ---------------------------------
> > | Dennis    | DennisR at dair.com    |
> > | Reinhardt | http://www.dair.com |
> >   ---------------------------------
> >
> >
> >
> > ------------------------------
> >
> > Message: 4
> > Date: Wed, 13 Dec 2006 18:57:16 -0800
> > From: "Anna Ravenscroft" <annaraven at gmail.com>
> > Subject: Re: [Baypiggies] Dec. 14 Meeting "Programming Productivity:
> >         What    Really Matters?"
> > To: "Dennis Reinhardt" <DennisR at dair.com>
> > Cc: Python <baypiggies at python.org>
> > Message-ID:
> >        
<cb361a610612131857r7a3a18c5u20344f1f13398cb7 at mail.gmail.com>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> > Okay - let me describe what I mean by "socializing".
> >
> > To me, socializing is not:
> >
> > "mapping" (mapping is a formal structure grouping up people and the
> > grouping process seems to take forever.)
> >
> > dinner (getting stuck next to someone I've never met and have
nothing
> > in common with and having to make smalltalk with them for the next
> > hour is my idea of hell.)
> >
> > extending the Q&A session after a presentation - leaving those of us
> > who have heard enough stuck with the choice of being *rude* or
waiting
> > patiently in hopes that eventually we can stand up and go talk to
> > someone we have been wanting to talk with - which usually happens
> > about 5 minutes before we're kicked out of the room...
> >
> > Milling around in the lobby of google waiting to fill out a badge
and
> > be shepherded up to a room just in time for the presentation to
start.
> > Not everyone is there, and we're usually rather distracted.
> >
> > Socializing - what I'm asking for - is a chance to talk to people,
_by
> > choice_ -- not by enforced proximity or structured format --
including
> > the chance to walk around and talk to more than one person. Having
> > snacks and beverages is nice.
> >
> > I would like a chance to socialize.
> >
> > Cordially,
> > Anna
> >
> >
> > ------------------------------
> >
> > Message: 5
> > Date: Wed, 13 Dec 2006 21:56:50 -0800
> > From: Marilyn Davis <marilyn at deliberate.com>
> > Subject: Re: [Baypiggies] Dec. 14 Meeting "Programming Productivity:
> >         What    Really Matters?"
> > To: baypiggies at python.org
> > Message-ID: <20061214055653.9296D1E4006 at bag.python.org>
> > Content-Type: text/plain; charset="ISO-8859-1"
> >
> >
> > ----- On Wednesday, December 13, 2006 annaraven at gmail.com wrote:
> >
> > > Okay - let me describe what I mean by "socializing".
> > >
> > > To me, socializing is not:
> > >
> > > "mapping" (mapping is a formal structure grouping up people and
the
> > > grouping process seems to take forever.)
> > >
> > > dinner (getting stuck next to someone I've never met and have
nothing
> > > in common with and having to make smalltalk with them for the next
> > > hour is my idea of hell.)
> > >
> > > extending the Q&A session after a presentation - leaving those of
us
> > > who have heard enough stuck with the choice of being *rude* or
waiting
> > > patiently in hopes that eventually we can stand up and go talk to
> > > someone we have been wanting to talk with - which usually happens
> > > about 5 minutes before we're kicked out of the room...
> > >
> > > Milling around in the lobby of google waiting to fill out a badge
and
> > > be shepherded up to a room just in time for the presentation to
start.
> > > Not everyone is there, and we're usually rather distracted.
> >
> > Yeh.  We are not allowed in early, as far as I know.  The lobby is
not the
> > right thing.  We're not there yet.
> >
> > Google is providing snacks?  How do the snacks get snacked upon if
the
> > program starts when people first arrive?
> >
> > So far, it seems to me, this little disagreement we are having is
divided
> > against the gender axis.  Just commenting, I don't have any
judgement or
> > conclusion about it, I just find it interesting.
> >
> > I'm looking forward to whatever part I'm able to get to.
> >
> > Marilyn
> >
> > >
> > > Socializing - what I'm asking for - is a chance to talk to people,
_by
> > > choice_ -- not by enforced proximity or structured format --
including
> > > the chance to walk around and talk to more than one person. Having
> > > snacks and beverages is nice.
> > >
> > > I would like a chance to socialize.
> > >
> > > Cordially,
> > > Anna
> > > _______________________________________________
> > > Baypiggies mailing list
> > > Baypiggies at python.org
> > > http://mail.python.org/mailman/listinfo/baypiggies
> >
> >
> >
> >
> > ------------------------------
> >
> > Message: 6
> > Date: Wed, 13 Dec 2006 22:06:25 -0800
> > From: "Anna Ravenscroft" <annaraven at gmail.com>
> > Subject: Re: [Baypiggies] Dec. 14 Meeting "Programming Productivity:
> >         What    Really Matters?"
> > To: "Marilyn Davis" <marilyn at deliberate.com>
> > Cc: baypiggies at python.org
> > Message-ID:
> >        
<cb361a610612132206i163aad6frfebd13274094cdac at mail.gmail.com>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> > On 12/13/06, Marilyn Davis <marilyn at deliberate.com> wrote:
> > >
> > > ----- On Wednesday, December 13, 2006 annaraven at gmail.com wrote:
> > >
> > > Yeh.  We are not allowed in early, as far as I know.  The lobby is
not the
> > right thing.  We're not there yet.
> > >
> > > Google is providing snacks?  How do the snacks get snacked upon if
the
> > program starts when people first arrive?
> > >
> > > So far, it seems to me, this little disagreement we are having is
divided
> > against the gender axis.  Just commenting, I don't have any
judgement or
> > conclusion about it, I just find it interesting.
> > >
> >
> > The main disagreement I really see is a different definition of
> > socializing. Which is why I posted my definition so we could have
the
> > discussion be more clear. Some people apparently consider the lobby
> > milling or the mapping to be socializing. That's okay for them to
have
> > that definition - but it's not what I was asking for when I asked
for
> > a chance to socialize, and so I figured it would be easier to
discuss
> > if we had a definition on the table. (whether for people to agree or
> > disagree with - at least we're not assuming what it means.) Once we
> > agree on what it means to "socialize" we can agree on whether we
want
> > a socializing time.
> >
> > > I'm looking forward to whatever part I'm able to get to.
> >
> > Me too. I'm sure the presentation will be great. I hope I get a
chance
> > to chat with you. I haven't had much opportunity for that.
> >
> > --
> > cordially,
> > Anna
> > --
> > It is fate, but call it Italy if it pleases you, Vicar!
> >
> >
> > ------------------------------
> >
> > Message: 7
> > Date: Wed, 13 Dec 2006 22:54:46 -0800
> > From: "Alex Martelli" <aleax at google.com>
> > Subject: Re: [Baypiggies] Dec. 14 Meeting "Programming Productivity:
> >         What    Really Matters?"
> > To: "Marilyn Davis" <marilyn at deliberate.com>
> > Cc: baypiggies at python.org
> > Message-ID:
> >        
<55dc209b0612132254y6ea79c01h257c2d515fbe6fd6 at mail.gmail.com>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> > On 12/13/06, Marilyn Davis <marilyn at deliberate.com> wrote:
> >    ...
> > > So far, it seems to me, this little disagreement we are having is
divided
> > against the gender axis.  Just commenting, I don't have any
judgement or
> > conclusion about it, I just find it interesting.
> >
> > OK, so let me weigh in...: I _know_ I'm going to be seriously tired
> > tomorrow night, except (perhaps, with some luck:-) very early on, as
> > I'm going to have a long and intense workday before it; so, from my
> > subjective POV the tradeoff is -- am I going to be dozing at the end
> > of the presentation (if we have socialtime _before_), or am I going
to
> > be dozing through socialtime (if we have it _after_).  Overall, I'd
> > (marginally) prefer the first option.
> >
> > Sorry to spoil the nice gender-axis alignment, but then, I tend to
do
> > that (I guess that, according to our great State's great governor,
> > this makes me a "girlyman":-).
> >
> >
> > > I'm looking forward to whatever part I'm able to get to.
> >
> > Likewise, except s/get to/be awake for/ :-).
> >
> >
> > Alex
> >
> >
> > ------------------------------
> >
> > _______________________________________________
> > Baypiggies mailing list
> > Baypiggies at python.org
> > http://mail.python.org/mailman/listinfo/baypiggies
> >
> >
> > End of Baypiggies Digest, Vol 14, Issue 16
> > ******************************************
> >
> >
> >
> > _______________________________________________
> > Baypiggies mailing list
> > Baypiggies at python.org
> > http://mail.python.org/mailman/listinfo/baypiggies
> >
> 
> 
> -- 
> Russell Whitaker
> Sysops Tools Team Lead
> http://www.corp.google.com/~whitaker/
> "From the point of view of any orthodoxy, myth might be defined as
> 'other people's
> religion'... to which an equivalent definition of religion might be
> 'misunderstood mythology'."
> - Joseph Campbell, "The Hero with a Thousand Faces"
> _______________________________________________
> Baypiggies mailing list
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