better abstract
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@ -176,7 +176,7 @@ salvis-overlaid-visvalingam-64-chaikin-50k_QUADRANT = 1
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REF = $(shell git describe --abbrev=12 --always --dirty)
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REF = $(shell git describe --abbrev=12 --always --dirty)
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version.inc.tex: Makefile $(shell git rev-parse --git-dir 2>/dev/null)
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version.inc.tex: Makefile $(shell git rev-parse --git-dir 2>/dev/null)
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TZ=UTC date '+\gdef\VCDescribe{%F ($(REF))}%' > $@
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TZ=UTC date '+\gdef\VCDescribe{%F (revision $(REF))}%' > $@
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vars.inc.tex: vars.awk wm.sql Makefile
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vars.inc.tex: vars.awk wm.sql Makefile
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awk -f $< wm.sql
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awk -f $< wm.sql
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@ -91,12 +91,11 @@
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\label{sec:abstract}
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\label{sec:abstract}
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Currently available line simplification algorithms are rooted in mathematics
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Currently available line simplification algorithms are rooted in mathematics
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and geometry, and are not fit bendy natural features like rivers and
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and geometry, and are unfit for natural features like rivers and
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coastlines. This paper discusses our implementation of {\WM} algorithm,
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coastlines. {\WM} algorithm is derived from cartographic knowledge, and
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with notes that we would have been appreciated before starting the
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thus is well suited for natural features. We also documented our
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re-implementation endeavor. This paper accompanies our implementation of
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implementation, which allows anyone understand the algorithm and our
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{\WM} algorithm and will be helpful to anyone trying to understand the
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implementation in detail.
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original {\WM} paper, or our implementation.
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\end{abstract}
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\end{abstract}
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@ -120,18 +119,19 @@ Textwidth in cm: {\printinunitsof{cm}\prntlen{\textwidth}}
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When creating small-scale maps, often the detail of the data source is greater
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When creating small-scale maps, often the detail of the data source is greater
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than desired for the map. While many features can be removed or simplified, it
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than desired for the map. While many features can be removed or simplified, it
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is more tricky with natural features that have many bends, like coastlines,
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is more tricky with natural features that have many bends, like coastlines,
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rivers and forest boundaries.
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rivers or forest boundaries.
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To create a small-scale map from a large-scale data source, features need to be
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To create a small-scale map from a large-scale data source, features need to be
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generalized: detail should be reduced. While performing the generalization, it
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generalized, i.e. detail should be reduced. While performing the generalization, it
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is important to retain the "defining" shape of the original feature. Otherwise,
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is important to retain the "defining" shape of the original feature. Otherwise,
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if the generalized feature looks too different than the original, the result
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if the generalized feature looks too different than the original, the result
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will look unrealistic.
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will look unrealistic.
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For example, if a river is nearly straight, it should be nearly straight after
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For example, if a river is nearly straight, it should be nearly straight after
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generalization, otherwise a too straightened river will look like a canal.
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generalization. A too straightened river will look like a canal, and the other
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Conversely, if the river is highly wiggly, the number of bends should be
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way around --- too curvy would not reflect the natural shape. Conversely, if
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reduced, but not removed altogether.
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the river is highly wiggly, the number of bends should be reduced, but not
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removed altogether.
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Generalization problem for other objects can often be solved by other
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Generalization problem for other objects can often be solved by other
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non-geometric means:
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non-geometric means:
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