commit 4695f9e8c3f2287ce225a79c58211c38f406fd15 (tree)
parent e3958fcca6c85d2710f2a035311a41716821601b
Author: Motiejus Jakštys <motiejus@uber.com>
Date: Tue, 11 May 2021 23:59:26 +0300
address more andriub comments
Diffstat:
| M | IV/mj-msc.tex | | | 54 | ++++++++++++++++++++++++++++++++++++------------------ |
1 file changed, 36 insertions(+), 18 deletions(-)
diff --git a/IV/mj-msc.tex b/IV/mj-msc.tex
@@ -321,6 +321,13 @@ figure~\onpage{fig:salvis-generalized-chaikin-50k}.
\label{fig:salvis-overlaid-generalized-chaikin-50k}
\end{figure}
+\begin{figure}[b!]
+ \centering
+ \includegraphics[width=.9\textwidth]{amalgamate1}
+ \caption{Narrow bends amalgamating into large unintelligible blobs.}
+ \label{fig:pixel-amalgamation}
+\end{figure}
+
The resulting simplified and smoothened example
(figure~\onpage{fig:salvis-generalized-chaikin-50k}) yields a more
aesthetically pleasing result, however, it obscures natural river features.
@@ -351,12 +358,6 @@ classical algorithms would remove these bends altogether. A cartographer would
retain a few of those distinctive bends, but would increase the distance
between the bends, remove some of the bends, or both.
-\begin{figure}[ht]
- \includegraphics[width=\textwidth]{amalgamate1}
- \caption{Narrow bends amalgamating into large unintelligible blobs.}
- \label{fig:pixel-amalgamation}
-\end{figure}
-
For the reasons discussed in this section, the "classical" {\DP} and {\VW} are
not well suited for natural river generalization, and a more robust line
generalization algorithm is worthwhile for to look for.
@@ -385,8 +386,6 @@ have emerged. These modern replacements fall into roughly two categories:
\end{itemize}
-% TODO: [Šioje vietoje turi būti WM algoritmo pristatymas su iliustracijomis. Turi būti bent minimalus, ne sakinio, paaiškinimas, kodėl algoritmas tinkamas kartografijai. Kodėl jis pasirinktas realizuoti - o čia ir Tomas ir aš buvome parašę email: išlaikant raiškius naturalių objektų kontūrus, generalizacijos rezultatas žemėlapyje geriau atspindi gamtinės aplinkos savybes, pvz. upių vingiuotumą, kuris gali atspindėti reljefo bei kitas paviršiaus savybes ir pan.]
-
Authors of most of the aforementioned articles have implemented the
generalization algorithm, at least to generate the illustrations in the
articles. However, code is not available for evaluation with a desired data
@@ -395,6 +394,34 @@ set, much less for use as a basis for creating new maps. To author's knowledge,
purchase of the commercial product suite, without a way to license the
standalone algorithm.
+{\WM} algorithm was created by encoding professional cartographers' knowledge
+into a computer algorithm. It has a few main properties which make it
+especially suitable for generalization of natural linear features:
+
+\begin{itemize}
+ \item Small bends are not always removed, but either combined (for example,
+ 3 bends into 2), exaggerated, or removed, depending on the neighboring
+ bends.
+ \item Long and gentle bends are not straightened, but kept as-is.
+\end{itemize}
+
+\begin{figure}[h]
+ \centering
+ \includegraphics[width=.8\textwidth]{wang125}
+ \caption{Originally figure 12.5: cartographic line generalization example.}
+ \label{fig:wang125}
+\end{figure}
+
+As a result of these properties, {\WM} algorithm retains the defining
+properties of the natural features; high-current rivers keep their appearance
+as such, instead of becoming canals; low-stream bendy rivers retain their
+frequent small bends.
+
+Figure~\ref{fig:wang125} (from the original \titlecite{wang1998line})
+illustrates the {\WM} algorithm (the figure labeled "proposed method").
+
+% TODO DONE: [Šioje vietoje turi būti WM algoritmo pristatymas su iliustracijomis. Turi būti bent minimalus, ne sakinio, paaiškinimas, kodėl algoritmas tinkamas kartografijai. Kodėl jis pasirinktas realizuoti - o čia ir Tomas ir aš buvome parašę email: išlaikant raiškius naturalių objektų kontūrus, generalizacijos rezultatas žemėlapyje geriau atspindi gamtinės aplinkos savybes, pvz. upių vingiuotumą, kuris gali atspindėti reljefo bei kitas paviršiaus savybes ir pan.]
+
\subsection{Problematic with generalization of rivers}
% DONE subscection: andriub: Į šį skyrių turi būti perkeltas tekstas iš From Simplification to Generalization ir mano pakomentuota dalis iš Modern approaches skyriaus.
@@ -495,19 +522,10 @@ We are limiting the problem to cartographic line generalization. That is, full
cartographic generalization, which takes topology and other feature classes
into account, is out of scope.
-Figure~\ref{fig:wang125} illustrates {\WM} algorithm from their original
+Figure~\onpage{fig:wang125} illustrates {\WM} algorithm from their original
paper. Note how the long bends retain curvy, and how some small bends got
exaggerated.
-\begin{figure}[ht]
- \centering
- \includegraphics[width=.8\textwidth]{wang125}
-
- \caption{Originally figure 12.5: cartographic line generalization example.}
-
- \label{fig:wang125}
-\end{figure}
-
\section{Methodology}
\label{sec:methodology}
% andriub: Šio skyriaus poskyriai turėtų būti išdėstyti tokia tvarka:
