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Motiejus Jakštys 2021-05-16 17:34:04 +03:00
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commit b9f511a860
2 changed files with 65 additions and 37 deletions
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24
IV/Makefile
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@ -40,9 +40,10 @@ RIVERS = \
salvis-visvalingam-64-chaikin-50k \
salvis-overlaid-douglas-64-chaikin-50k \
salvis-overlaid-visvalingam-64-chaikin-50k \
salvis-wm-50k \
salvis-wm-250k \
salvis-wm-overlaid-50k-zoom \
salvis-wm-50k \
salvis-wm-50k-nw \
salvis-wm-50k-ne \
salvis-wm-overlaid-250k-zoom \
salvis-gdr50-overlaid
@ -199,15 +200,22 @@ 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-50k_1SELECT = wm_visuals where name='salvis-wm-75'
salvis-wm-50k_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-wm-75'
salvis-wm-overlaid-50k-zoom_2SELECT = wm_visuals where name='salvis'
salvis-wm-overlaid-50k-zoom_1COLOR = orange
salvis-wm-50k_1SELECT = wm_visuals where name='salvis-wm-75'
salvis-wm-50k_2SELECT = wm_visuals where name='salvis'
salvis-wm-50k_1COLOR = orange
salvis-wm-50k-nw_1SELECT = wm_visuals where name='salvis-wm-75'
salvis-wm-50k-nw_2SELECT = wm_visuals where name='salvis'
salvis-wm-50k-nw_1COLOR = orange
salvis-wm-50k-nw_QUADRANT = 2
salvis-wm-50k-ne_1SELECT = wm_visuals where name='salvis-wm-75'
salvis-wm-50k-ne_2SELECT = wm_visuals where name='salvis'
salvis-wm-50k-ne_1COLOR = orange
salvis-wm-50k-ne_QUADRANT = 1
salvis-wm-overlaid-250k-zoom_1SELECT = wm_visuals where name='salvis-wm-220'
salvis-wm-overlaid-250k-zoom_2SELECT = wm_visuals where name='salvis'

78
IV/mj-msc.tex
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@ -1378,45 +1378,49 @@ table~\ref{table:scale-halfcirlce-diameter}:
\subsubsection{Medium-scale (1:\numprint{50000})}
\label{sec:analyzed-medium-scale}
\begin{figure}[ht]
\begin{figure}[h!]
\centering
\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}.}
\includegraphics[width=\textwidth]{salvis-wm-50k}
\caption{2x zoomed-in {\WM} for 1:\numprint{50000}.}
\label{fig:salvis-wm-50k}
\end{figure}
As one can see in figure~\ref{fig:salvis-wm-50k}, the illustrations deliver
what was promised by the algorithm, but with a few caveats. West-side of the
river looks reasonably well simplified: long bends remain slightly curved,
what was promised by the algorithm, but with a few caveats. Left side of the
figure looks reasonably well simplified: long bends remain slightly curved,
small bends are removed or slightly exaggerated.
Approximately at the middle of the figure some jagged and sharp bends appear.
Figure~\ref{fig:salvis-wm-50k-overlaid-zoom} zooms in, overlaying the original
river (in orange). These will become more pronounced in even larger-scale
Figure's~\ref{fig:salvis-wm-50k} left part is clipped to
figure~\ref{fig:salvis-wm-50k-nw}. As one can see, some bends were well
exaggerated, and some bends were eliminated.
\begin{figure}[h!]
\centering
\includegraphics[width=\textwidth]{salvis-wm-50k-nw}
\caption{Left part of figure~\ref{fig:salvis-wm-50k}.}
\label{fig:salvis-wm-50k-nw}
\end{figure}
Top--right side (clipped in figure~\ref{fig:salvis-wm-50k-ne}) some jagged
and sharp bends appear. These will become more pronounced in even larger-scale
simplification in the next section.
\begin{figure}[ht]
\begin{figure}[h!]
\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}
\includegraphics[width=\textwidth]{salvis-wm-50k-ne}
\caption{Top--right part of figure~\ref{fig:salvis-wm-50k}.}
\label{fig:salvis-wm-50k-ne}
\end{figure}
To sum up, mid-scale simplification works well for some geometries, but creates
sharp edges for others.
\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).
simplification and overlays the original.
\begin{figure}[ht]
\centering
@ -1431,7 +1435,7 @@ simplification and overlays the original (in orange).
\includegraphics[width=.2\textwidth]{salvis-wm-250k}
\caption{Simplified.}
\end{subfigure}
\caption{Simplified with {\WM} for 1:\numprint{250000}.}
\caption{GDB10LT simplified with {\WM} for 1:\numprint{250000}.}
\label{fig:salvis-wm-250k}
\end{figure}
@ -1442,11 +1446,27 @@ simplification and overlays the original (in orange).
\label{fig:salvis-wm-250k-overlaid-zoom}
\end{figure}
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 figure~\ref{fig:salvis-wm-50k} (of scale 1:\numprint{50000}) has many
smaller bends at approximately the same location.
A conglomeration of bends is visible, especially in top--right side of the
illustration. We assume this was caused by two bends significantly exaggerated,
leaving no space to exaggerate for those between the two.
\subsubsection{Discussion}
For mid-size scales of 1:\numprint{50000}, the implemented algorithm works well
for certain geometries, and poorly for others. This test surfaced two areas for
future research and improvement:
\begin{itemize}
\item Exaggeration is sometimes creating sharp edges, especially when the
exaggerated bend is quite small. When sharp edges are created,
exaggeration could interpolate more points in the bend, and exaggerate
using the interpolated points.
\item In larger scales, when bends do not have space to exaggerate, they
should be combined or eliminated instead.
\end{itemize}
\subsection{Comparing Generalized Result with National Spatial Datasets}
@ -1547,7 +1567,7 @@ implementation:
\item Fine-tune parameters for bend exaggeration.
Section~\ref{sec:generalization-results-of-analyzed-rivers} contains
a exaggerated bends that became sharp.
a exaggerated bends that became sharp and includes some future ideas.
\item Research when bends should be marked as \textsc{isolated}. As is
seen from examples, the current criteria is not robust enough.