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more analysis for 1:50k and 1:250k.

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Motiejus Jakštys 2021-05-15 16:35:33 +03:00
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26
IV/Makefile
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@ -40,8 +40,10 @@ RIVERS = \
salvis-visvalingam-64-chaikin-50k \
salvis-overlaid-douglas-64-chaikin-50k \
salvis-overlaid-visvalingam-64-chaikin-50k \
salvis-wm-75-50k \
salvis-wm-220-250k
salvis-wm-50k \
salvis-wm-250k \
salvis-wm-overlaid-50k-zoom \
salvis-wm-overlaid-250k-zoom
#################################
# The thesis, publishable version
@ -193,15 +195,19 @@ salvis-overlaid-visvalingam-64-chaikin-50k_1COLOR = orange
salvis-overlaid-visvalingam-64-chaikin-50k_WIDTHDIV = 2
salvis-overlaid-visvalingam-64-chaikin-50k_QUADRANT = 1
salvis-wm-75-50k_1SELECT = wm_visuals where name='salvis'
salvis-wm-75-50k_2SELECT = wm_visuals where name='salvis-wm-75'
salvis-wm-75-50k_1COLOR = orange
salvis-wm-75-50k_WIDTHDIV = 2
salvis-wm-50k_1SELECT = wm_visuals where name='salvis-wm-75'
salvis-wm-50k_WIDTHDIV = 2
salvis-wm-220-250k_1SELECT = wm_visuals where name='salvis'
salvis-wm-220-250k_2SELECT = wm_visuals where name='salvis-wm-220'
salvis-wm-220-250k_1COLOR = orange
salvis-wm-220-250k_WIDTHDIV = 2
salvis-wm-250k_1SELECT = wm_visuals where name='salvis-wm-220'
salvis-wm-250k_WIDTHDIV = 10
salvis-wm-overlaid-50k-zoom_1SELECT = wm_visuals where name='salvis'
salvis-wm-overlaid-50k-zoom_2SELECT = wm_visuals where name='salvis-wm-75'
salvis-wm-overlaid-50k-zoom_1COLOR = orange
salvis-wm-overlaid-250k-zoom_1SELECT = wm_visuals where name='salvis'
salvis-wm-overlaid-250k-zoom_2SELECT = wm_visuals where name='salvis-wm-220'
salvis-wm-overlaid-250k-zoom_1COLOR = orange
.faux_db: db init.sql rivers.sql
bash db start

85
IV/mj-msc.tex
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@ -1333,34 +1333,89 @@ the algorithm.
\subsection{Generalization results of Analyzed Rivers}
Figure~\ref{fig:salvis-wm-75-50k} visualizes the generalization result for
Šalčia and Visinčia using {\WM} with the \textsc{dhalfcircle} values from
the table~\ref{table:scale-halfcirlce-diameter}:
Figures~\ref{fig:salvis-wm-50k} and~\ref{fig:salvis-wm-250k} visualize
the generalization result for Šalčia and Visinčia using {\WM} with the
\textsc{dhalfcircle} values from the
table~\ref{table:scale-halfcirlce-diameter}:
\begin{itemize}
\item 1:\numprint{50000}: 75 (figure~\ref{fig:salvis-wm-75-50k}).
\item 1:\numprint{250000}: 220 (figure~\ref{fig:salvis-wm-220-250k}).
\item 1:\numprint{50000}: 75.
\item 1:\numprint{250000}: 220.
\end{itemize}
The original feature is orange. As can be seen, some
isolated bends are exaggerated, and some small bends are removed.
\subsubsection{Mid-scale (1:\numprint{50000})}
\begin{figure}[ht]
\centering
\includegraphics[width=.5\textwidth]{salvis-wm-75-50k}
\caption{{\WM}-generalized river (1:{\numprint{50000}}).}
\label{fig:salvis-wm-75-50k}
\begin{subfigure}[b]{.49\textwidth}
\includegraphics[width=\textwidth]{salvis-50k}
\caption{Original.}
\end{subfigure}
\hfill
\begin{subfigure}[b]{.49\textwidth}
\centering
\includegraphics[width=\textwidth]{salvis-wm-50k}
\caption{Simplified.}
\end{subfigure}
\caption{Simplified with {\WM} for 1:\numprint{50000}.}
\label{fig:salvis-wm-50k}
\end{figure}
As one can see in figure~\ref{fig:salvis-wm-50k}, some of the small bends have
been exaggerated, and some removed. It mostly works as expected, except some of
the jagged lines approximately in the middle of the figure.
Figure~\ref{fig:salvis-wm-50k-overlaid-zoom} zooms in, overlaying the original
river (in orange).
\begin{figure}[ht]
\centering
\includegraphics[width=\textwidth]{salvis-wm-overlaid-50k-zoom}
\caption{2x zoomed-in {\WM} for 1:\numprint{50000}.}
\label{fig:salvis-wm-50k-overlaid-zoom}
\end{figure}
These will become
more pronounced in large-scale simplification in the next section. Other than
some sharp edges, this algorithm works reasonably well for mid-scale
simplification.
\subsubsection{Large-scale (1:\numprint{250000})}
As visible in figure~\ref{fig:salvis-wm-250k}, for large-scale map, some of the
resulting bends look significantly exaggerated. Why is that?
Figure~\ref{fig:salvis-wm-250k-overlaid-zoom} zooms in the large-scale
simplification and overlays the original (in orange).
\begin{figure}[ht]
\centering
\begin{subfigure}[b]{.49\textwidth}
\centering
\includegraphics[width=.2\textwidth]{salvis-250k}
\caption{Original.}
\end{subfigure}
\hfill
\begin{subfigure}[b]{.49\textwidth}
\centering
\includegraphics[width=.2\textwidth]{salvis-wm-250k}
\caption{Simplified.}
\end{subfigure}
\caption{Simplified with {\WM} for 1:\numprint{250000}.}
\label{fig:salvis-wm-250k}
\end{figure}
\begin{figure}[ht]
\centering
\includegraphics[width=.5\textwidth]{salvis-wm-220-250k}
\caption{{\WM}-generalized river (1:{\numprint{250000}}).}
\label{fig:salvis-wm-220-250k}
\includegraphics[width=\textwidth]{salvis-wm-overlaid-250k-zoom}
\caption{10x zoomed-in {\WM} for 1:\numprint{250000}.}
\label{fig:salvis-wm-250k-overlaid-zoom}
\end{figure}
% TODO: expand section and remove clear-page.
\clearpage
A conglomeration of bends is visible, especially in north-east side of the
center. We assume this was caused by two bends significantly exaggerated,
leaving no space to exaggerate for those between the two. For the same reason,
the 1:\numprint{50000} figure~\ref{fig:salvis-wm-50k} has many smaller bends
at approximately the same location.
\subsection{Generalization result comparison with national spatial data sets}