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Line vs. Polyline - what is the difference?   Timothie Biggs Apr 02, 2008
Re: Line vs. Polyline - what is the differe...   Dan Patterson Apr 02, 2008
Re: Line vs. Polyline - what is the differe...   Timothie Biggs Apr 02, 2008
Re: Line vs. Polyline - what is the differe...   Dan Patterson Apr 02, 2008
Re: Line vs. Polyline - what is the differe...   Stephen Lead Apr 02, 2008
Re: Line vs. Polyline - what is the differe...   William Huber Apr 02, 2008
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Subject Line vs. Polyline - what is the difference? 
Author Timothie Biggs 
Date Apr 02, 2008 
Message I'm just curious so if anyone can enlighten me or point towards some references in the help or anywhere...
 
  Tim 
   
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Subject Re: Line vs. Polyline - what is the difference? 
Author Dan Patterson 
Date Apr 02, 2008 
Message http://support.esri.com/index.cfm?fa=knowledgebase.gisDictionary.search&search=true&searchTerm=line
http://support.esri.com/index.cfm?fa=knowledgebase.gisDictionary.search&search=true&searchTerm=polyline
clear as mud? 
  Geomatics, Carleton University, Ottawa, Canada 
   
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Subject Re: Line vs. Polyline - what is the difference? 
Author Timothie Biggs 
Date Apr 02, 2008 
Message Yes indeed! I did look here but I'm not getting the difference...

I notice it's Lines for shapefiles and Polylines for Feature Classes....and that these are 2 distinct ArcObjects (however I am an absolute beginner with ArcObjects so haven't explored this avenue for an explanation)....

I am giving an in-house presentation about Editing and specifically Sketching and it got me thinking about Geometric Primitives...

Any more explanations out there anyone...?

 
  Tim 
   
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Subject Re: Line vs. Polyline - what is the difference? 
Author Dan Patterson 
Date Apr 02, 2008 
Message regardless of anyone elses descriptions I consider a line as that formed by two points, if the "line" consists of more than two points then it is a polyline (ie multiple line segments without duplicate points), if the line consists of discrete features then I consider them multipart lines/polylines...I am sure that others won't agree...but it gets me through the day :) 
  Geomatics, Carleton University, Ottawa, Canada 
   
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Subject Re: Line vs. Polyline - what is the difference? 
Author Stephen Lead 
Date Apr 02, 2008 
Message I think ESRI love to invent new terms for old things, and reuse old terms for new things, or call the same thing by different names.

eg an Item is also an Attribute or sometimes a Field. Domain can refer to valid values in a field, or the XY extent of your data. An XY layer used to be called an event theme, except now it can exist in your map or separately on disk.

At least we get to sound experienced when new people get confused by it all :) 
   
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Subject Re: Line vs. Polyline - what is the difference? 
Author William Huber 
Date Apr 02, 2008 
Message Stephen,

You make a good point. To an extent I am sympathetic with ESRI's plight, because it is the nature of GIS to unite various disciplines, including mathematics, computer science, and geography. These disciplines have developed differing technical terms for similar things and conflicting terms for different things. For instance, common important words like "union" and "merge" mean many different things, depending on the discipline; in relational database theory, a "view" is something quite different than a way to look at a map; while "line," "arc," "polyline," and "segment" have all been used for a similar concept (of a one-dimensional geometrical object described by a sequence of points occuring along it). Thus, ESRI people have somehow to master and unite these concepts and, at the same time, continue to evolve their software to reflect a growing and more diverse set of users and an ever changing set of software platforms and data models.

That being said, the definition of "line" Dan pointed us to is downright sloppy. Given ESRI's leadership in this area, it would be nice to see them move towards clearer, more precise terminology and definitions in their literature. 
  --Bill Huber
Quantitative Decisions (http://www.quantdec.com )
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