Global Mapper v26.0

Line won't Export

Roger Edrinn
Roger Edrinn Global Mapper UserTrusted User
edited January 2008 in Vector Data
I have a line on the border of my export that shows a state border, however it won't export.

I stretched the line over 5 deg of arc with only 2 verticies. It would appear that with my NAD83 projection, the line is "north" of the border and outside of my gridded output. When I expanded my export bounds, the line exported.

It would seem I have to add verticies and move the line to the grid line for my border.

My question? How many verticies do I need? Every deg? Every 30'? More?

Thanks

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  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited January 2008
    Did some testing. I put a vertex at 15' intervals and zoomed to 1:400 to place the vertex at the grid cross point, visually. Snapping does not exist to grid lines?

    If I set my export bounds to 49 deg the line was NOT exported. If I set my export bounds to 49.0001 deg the line was exported. Pretty touchy!!!

    Any words of wisdom from the Jedi Master?
  • global_mapper
    global_mapper Administrator
    edited January 2008
    What is the native projection of the layer that your line is in? It could be that if your line is not natively in lat/lon (i.e. you provided the coordinates in UTM or something), the reproject math causes it to fall just north of the 49 degree due to floating point roundoff, etc, making it not be included if you crop to exactly 49 degrees. I would suggest either doing your export just barely north of 49 degrees or having your boundary line be perhaps just south of 49 when you create it (say 48.999999, or less than a meter south of 49 exactly).

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited January 2008
    global_mapper wrote: »
    What is the native projection of the layer that your line is in? It could be that if your line is not natively in lat/lon (i.e. you provided the coordinates in UTM or something), the reproject math causes it to fall just north of the 49 degree due to floating point roundoff, etc, making it not be included if you crop to exactly 49 degrees.
    The original border shapefile came from the USGS seamless data site. So far as I know, everything is NAD83 from the USGS, so I've just standardize on that projection. A re-check confirmed it is indeed NAD83.

    Because I also had problems with the original shapfile not exporting, I deleted the straight portion along N49 and redrew a straight line. I then exported a new shapefile for my project.

    I would suggest either doing your export just barely north of 49 degrees or having your boundary line be perhaps just south of 49 when you create it (say 48.999999, or less than a meter south of 49 exactly).
    I've pretty much come to this same conclusion. Since my test at 49.0001 worked, I'll just do that. I just need a border for show. I don't want customers ragging on me because its not there.

    This is all about the difference between how you think it should work and how it actually works. Basically a metaphor of life.

    Thanks

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