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Re: [Maptitude] Re: Putting Inward Facing Tickmarks on Polygon Boundaries

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  • Josh Rosenthal
    Yup. Stupid error. foo = GetRecord( Survey Area Areas ) bar = GetArea(rh2id(foo)) pcoords = bar[3] showmessage(IsClockwise(pcoords)) Works as expected, and
    Message 1 of 8 , Mar 26, 2009
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      Yup.  Stupid error.

      foo = GetRecord("Survey Area Areas")
      bar = GetArea(rh2id(foo))
      pcoords = bar[3]
      showmessage(IsClockwise(pcoords))

      Works as expected, and confirms that indeed it appears to be a winding issue.

      On Thu, Mar 26, 2009 at 3:11 PM, Philip Villars <phil@...> wrote:

      Hi Josh,

      IsClockwise() returns a string, I think, not an array, therefore, it's not a valid argument to pass to ShowArray().  ShowMessage() should work, though.

      !.!.!.!.!.!.!.!.!.!.!.!.!.!.!.!

      Philip Villars
      Caliper Corporation
      1172 Beacon Street Suite 300 Newton MA 02461
      617-527-4700
      phil@...
      www.caliper.com


      From: Josh Rosenthal [mailto:maric423@...]
      To: Maptitude@yahoogroups.com
      Sent: Thu, 26 Mar 2009 14:54:27 -0400
      Subject: Re: [Maptitude] Re: Putting Inward Facing Tickmarks on Polygon Boundaries


      That sounds logical.  Didn't know about IsClockwise.  Mind you, I'm trying to use it, and I'm failing to get it to work, as follows.


      given a selected poly on the current layer,
      foo = GetRecord("Survey Area Areas")
      bar = GetArea(rh2id(foo))
      pcoords = bar[3]
      showarray(IsClockwise(pcoords))

      crashes on IsClockwise.

      Assuming for a moment that I'm just doing something stupid, and this is actually the issue. then presumably I'd loop through the layer, check the direction everything is wound, and then rebuild all the polys to wind the same way.  

      Assuming I can figure out how to use IsClockwise, that is.

      On Thu, Mar 26, 2009 at 2:16 PM, Moshe Haspel <mhaspel@...> wrote:

      Shot in the dark: could it have anything to do with whether a polygon is clockwise or not?

      Try using IsClockwise() to compare some with inward vs. outward ticks...



      --- In Maptitude@yahoogroups.com, Josh Rosenthal <maric423@...> wrote:
      >
      > Hi all,
      > A question for you all, that I'm hoping someone can offer a suggestion on.
      > Is it possible to style a consistently inward facing tickmark as a polygon
      > boundary? Clearly maptitude knows which side this would be, but when I
      > choose a given tickmark style (regular perpendicular ticks), on some
      > features they're facing inward, sometimes outward. Am I missing something
      > obvious?
      >
      > I'm trying to deal with a large collection of often overlapping polygons
      > (historic districts), which if filled would make the data within them
      > (historic properties) hard to view. Any other suggestions are welcome.
      >
      > Josh
      >



    • Kjartan Stefansson
      Josh, This is a side effect of the fact that Maptitude has topological databases. It knows when an area edge is shared by two neighbors and keeps track of it
      Message 2 of 8 , Mar 26, 2009
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        Josh,
         
        This is a side effect of the fact that Maptitude has topological databases.  It knows when an area edge is shared by two neighbors and keeps track of it as such.  This is very handy when it comes to editing, there is only one edge and when it is moved, there is no ambiguity and no overlaps or slivers are created.
         
        Maptitude also uses the topology information when drawing.  It knows the edge is shared and only draws it once.  This makes the drawing faster.  Unfortunately, for this example it means only one of the areas has the "inward" pattern.
         
        There are a few workarounds.  If your areas have a fill style, each area will be drawn fully, so you'll get the pattern you want.  Alternatively, you could export the file to a shape file.  That's a non-topological format where each polygon needs to be drawn independently.
         
        -Kjartan


        From: Maptitude@yahoogroups.com [mailto:Maptitude@yahoogroups.com] On Behalf Of Josh Rosenthal
        Sent: Thursday, March 26, 2009 12:49 PM
        To: maptitude
        Subject: [Maptitude] Putting Inward Facing Tickmarks on Polygon Boundaries

        Hi all,


        A question for you all, that I'm hoping someone can offer a suggestion on.  Is it possible to style a consistently inward facing tickmark as a polygon boundary?  Clearly maptitude knows which side this would be, but when I choose a given tickmark style (regular perpendicular ticks), on some features they're facing inward, sometimes outward.  Am I missing something obvious?  

        I'm trying to deal with a large collection of often overlapping polygons (historic districts), which if filled would make the data within them (historic properties) hard to view.  Any other suggestions are welcome.

        Josh

      • Josh Rosenthal
        Hmm, yeah, the areas are already non topologicals (necessarily in order to have the overlapping areas), constructed from polylines via larry s old trick of
        Message 3 of 8 , Mar 26, 2009
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          Hmm, yeah, the areas are already non topologicals (necessarily in order to have the overlapping areas), constructed from polylines via larry's old trick of exporting/importing through a text/geo.  It looks like we're just winding them according to the order of creation of the source polylines.  Should be able to either remedy it at the source, although I suspect writing an after the fact clockwise standardizer would be more likely to come in handy in the future.

          In any case, much obliged to everyone for your help.

          Josh

          On Thu, Mar 26, 2009 at 3:24 PM, Kjartan Stefansson <kjartan@...> wrote:

          Josh,
           
          This is a side effect of the fact that Maptitude has topological databases.  It knows when an area edge is shared by two neighbors and keeps track of it as such.  This is very handy when it comes to editing, there is only one edge and when it is moved, there is no ambiguity and no overlaps or slivers are created.
           
          Maptitude also uses the topology information when drawing.  It knows the edge is shared and only draws it once.  This makes the drawing faster.  Unfortunately, for this example it means only one of the areas has the "inward" pattern.
           
          There are a few workarounds.  If your areas have a fill style, each area will be drawn fully, so you'll get the pattern you want.  Alternatively, you could export the file to a shape file.  That's a non-topological format where each polygon needs to be drawn independently.
           
          -Kjartan


          From: Maptitude@yahoogroups.com [mailto:Maptitude@yahoogroups.com] On Behalf Of Josh Rosenthal
          Sent: Thursday, March 26, 2009 12:49 PM
          To: maptitude
          Subject: [Maptitude] Putting Inward Facing Tickmarks on Polygon Boundaries

          Hi all,


          A question for you all, that I'm hoping someone can offer a suggestion on.  Is it possible to style a consistently inward facing tickmark as a polygon boundary?  Clearly maptitude knows which side this would be, but when I choose a given tickmark style (regular perpendicular ticks), on some features they're facing inward, sometimes outward.  Am I missing something obvious?  

          I'm trying to deal with a large collection of often overlapping polygons (historic districts), which if filled would make the data within them (historic properties) hard to view.  Any other suggestions are welcome.

          Josh


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