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proper sinewave comparisons

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Motiejus Jakštys 2020-05-26 14:17:39 +03:00
parent a8dc7e82d5
commit 82b4400474
2 changed files with 42 additions and 19 deletions
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14
II/Referatas/Makefile
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@ -1,12 +1,13 @@
ZEIMENA_TOLERANCES = 100 125 250 500 1000 2000 4000
SINEWAVE_TOLERANCES = 4 5
SINEWAVE_TOLERANCES = 1 2 3 4
GEN = $(addsuffix .pdf, \
$(addprefix sinewave-douglas-,$(SINEWAVE_TOLERANCES)) \
$(addprefix sinewave-visvalingam-,$(SINEWAVE_TOLERANCES)) \
$(addprefix zeimena-douglas-,$(ZEIMENA_TOLERANCES)) \
$(addprefix zeimena-visvalingam-,$(ZEIMENA_TOLERANCES)))
mj-referatas.pdf: mj-referatas.tex version.tex bib.bib zeimena-pretty.pdf \
sinewave.pdf sinewave-douglas-5.pdf $(GEN)
sinewave.pdf $(GEN)
latexmk -g -pdf $<
define algo2img
@ -15,12 +16,13 @@ db/.faux_$(1)-$(2)-%: $(2).sql db/.faux_ready
touch $$@
$(1)-$(2)-%.pdf: layer2img.py db/.faux_$(1)-$(2)-%
./layer2img.py --table=$(1)_$(2)_$$* --size=52x74 --outfile $(1)-$(2)-$$*.pdf
./layer2img.py --table=$(1)_$(2)_$$* --size=$(3) --outfile $(1)-$(2)-$$*.pdf
endef
$(eval $(call algo2img,sinewave,douglas))
$(eval $(call algo2img,zeimena,douglas))
$(eval $(call algo2img,zeimena,visvalingam))
$(eval $(call algo2img,sinewave,douglas,52x12))
$(eval $(call algo2img,sinewave,visvalingam,52x12))
$(eval $(call algo2img,zeimena,douglas,52x74))
$(eval $(call algo2img,zeimena,visvalingam,52x74))
sinewave.gpkg: sinewave.py
./sinewave.py

47
II/Referatas/mj-referatas.tex
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@ -169,11 +169,11 @@ are comparable?), {\DP} tolerance was arbitrarily squared and fed to {\VW}. To
author's eye, this provides comparable and reasonable results, though could be
researched.
As can be observed in table~\ref{tab:dp-vs-vw} on page~\pageref{tab:dp-vs-vw},
both simplication algorithms convert bends to chopped lines. This is especially
visible in tolerances 250 and 500. In a more robust simplification algorithm,
the larger tolerance, the larger the bends on the original map should be
retained.
As can be observed in table~\ref{tab:comparison-zeimena} on
page~\pageref{tab:comparison-zeimena}, both simplication algorithms convert
bends to chopped lines. This is especially visible in tolerances 250 and 500.
In a more robust simplification algorithm, the larger tolerance, the larger the
bends on the original map should be retained.
\begin{figure}[H]
\renewcommand{\tabularxcolumn}[1]{>{\center\small}m{#1}}
@ -206,12 +206,11 @@ retained.
\includegraphics[width=.0625\linewidth]{zeimena-douglas-4000} &
\includegraphics[width=.0625\linewidth]{zeimena-visvalingam-4000} \tabularnewline \hline
\end{tabularx}
\caption{{\DP} and {\VW} side-by-side visual comparison}
\label{tab:dp-vs-vw}
\caption{{\DP} and {\VW} side-by-side on Žeimena}
\label{tab:comparison-zeimena}
\end{figure}
To sum up, both {\VW} and {\DP} simplify the lines, but their cartographic
output poorly represents lines and bends. Where to look for better output?
@ -234,13 +233,35 @@ straight line, but too small to retain both and retain their complexity.
\end{figure}
When one applies {\DP} to figure~\ref{pic:sinewave}, either both bends remain,
or become a straight line.
or become a straight line, see table~\ref{tab:comparison-sinewave} on
page~\pageref{tab:comparison-sinewave}.
\begin{figure}[h]
\centering
\includegraphics[width=52mm]{sinewave-douglas-5}
\caption{Example bend, generalized}
\label{pic:sinewave-douglas-5}
\renewcommand{\tabularxcolumn}[1]{>{\center\small}m{#1}}
\begin{tabularx}{\textwidth}{ p{1.5cm} | X | X | }
Tolerance DP/VW &
Douglas \& Peucker &
Visvalingam-Whyatt \tabularnewline \hline
1/1 &
\includegraphics[width=\linewidth]{sinewave-douglas-1} &
\includegraphics[width=\linewidth]{sinewave-visvalingam-1} \tabularnewline \hline
2/4 &
\includegraphics[width=\linewidth]{sinewave-douglas-2} &
\includegraphics[width=\linewidth]{sinewave-visvalingam-2} \tabularnewline \hline
3/9 &
\includegraphics[width=\linewidth]{sinewave-douglas-3} &
\includegraphics[width=\linewidth]{sinewave-visvalingam-3} \tabularnewline \hline
4/16 &
\includegraphics[width=\linewidth]{sinewave-douglas-4} &
\includegraphics[width=\linewidth]{sinewave-visvalingam-4} \tabularnewline \hline
\end{tabularx}
\caption{{\DP} and {\VW} on example wave}
\label{tab:comparison-sinewave}
\end{figure}
\section{Related Work and future suggestions}