[GPlates-discuss] "Fill polygons" question

Christian Heine christian.heine at sydney.edu.au
Wed Nov 6 15:55:45 AEDT 2013


Hi Michael,

> I would like to apply the "Fill polygons" option to the Seton_etal_ESR2012_Coastlines_2012.1.gpmlz layer that is included with GPlates 1.3. When I check the box, nothing happens,

Simple explanation: the coastlines are not closed (it's like trying to fill a line in Inkscape/Illustrator - unless you close it you can't fill it). As in a GIS sense that the x_1 y_1 != x_n y_n (ie first vertex of the line = last vertex). 

Try the coastline data from here: 
ftp://ftp.earthbyte.org/earthbyte/GPlates/SampleData/FeatureCollections/Coastlines

these should be properly closed polygons.

> however it works correctly for the Seton_etal_ESR2012_StaticPolygons_2012.1.gpmlz layer. What's also strange is the "Fill polylines" option partially fills the continents for the Coastlines layer but does nothing when applied to the StaticPolygons layer.

See above - the lines are just filled by connecting both end point vertices. The polygons are polygons, hence filling the lines will not work here.

> Should both options work for both layers?

No.

> Maybe the different layers use different graphical objects, each of which requires a different fill function?

No.

HTH,
Christian




-- 
 Dr Christian Heine
 Senior Research Fellow
 EarthByte Research Group, School of Geosciences
 The University of Sydney, Australia

 P +61 2 9114 0997
 http://www.geosci.usyd.edu.au/people/st_heine.shtml
 http://www.earthbyte.org/people/christian

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