diff --git a/II/Referatas/mj-referatas.tex b/II/Referatas/mj-referatas.tex index 45e8a37..aeba9f7 100644 --- a/II/Referatas/mj-referatas.tex +++ b/II/Referatas/mj-referatas.tex @@ -6,6 +6,7 @@ \usepackage[english]{babel} \usepackage[maxbibnames=99,style=authoryear]{biblatex} \usepackage[pdfusetitle]{hyperref} +\usepackage{enumitem} \addbibresource{bib.bib} \usepackage{caption} \usepackage{subcaption} @@ -16,6 +17,9 @@ \usetikzlibrary{er,positioning} \input{version} +\newcommand{\DP}{Douglas \& Peucker} +\newcommand{\VW}{Visvalingam-Whyatt} + \title{ Cartografic Generalization of Lines \\ (example of rivers) \\ \vspace{4mm} @@ -28,8 +32,6 @@ http://bl.ocks.org/msbarry/9152218 small scale: 1:XXXXXX large scale: 1:XXX -take douglas-pecker and check for different scales. - a4: 210x297mm a6: 105x148xmm a7: 74x105mm @@ -41,15 +43,6 @@ connect rivers first to a single polylines: ideal hypothesis: mueller algorithm + topology may fully realize cartographic generalization tasks. what scales and what distances? - -https://postgis.net/docs/ST_SimplifyVW.html -https://postgis.net/docs/ST_Simplify.html -https://postgis.net/docs/ST_SimplifyPreserveTopology.html - -how is tolerance bound to scale? -- just use same parameter. - - \fi \author{Motiejus Jakštys} @@ -120,7 +113,7 @@ general public: For comparison reasons, this article will be using Lakaja and large part of Žeimena (see figure~\ref{fig:zeimena} on page~\pageref{fig:zeimena}). This location was -chosen because it is a combination of straight and curved river shape, +chosen because the river exhibits both both straight and curved shape, is a combination of two curly rivers, and author's familiarity with the location. \begin{figure} @@ -132,6 +125,20 @@ combination of two curly rivers, and author's familiarity with the location. \section{Mathematical and geometrical algorithms} +To visually evaluate the sample above, we created a few examples for {\DP} +and {\VW} using the following parameters: + +\begin{enumerate}[label=(\Roman*)] + \item {\DP} tolerance: $tolerance := 125 * 2^n, n = 0,1,...,5$. + \item {\VW} tolerance: $vwtolerance = tolerance ^ 2$\label{itm:2}. +\end{enumerate} + +Item~\ref{itm:2} requires explanation. Tolerance for {\DP} is specified in +linear units, in this case, meters. Tolerance for {\VW} is specified in areal +units, in this case, square meters $m^2$. As author was not able to locate +formal comparisons between the two (i.e. how to calculate one tolerance value +from another, so the results are comparable?), {\DP} tolerance was arbitrarily +squared. To the author's understanding, this provides reasonalbe results. \renewcommand{\tabularxcolumn}[1]{>{\center\small}m{#1}} \begin{tabularx}{\textwidth}{ p{1.5cm} | X | X | } diff --git a/II/Referatas/zeimena.gpkg b/II/Referatas/zeimena.gpkg index 8e3e2d1..354483e 100644 Binary files a/II/Referatas/zeimena.gpkg and b/II/Referatas/zeimena.gpkg differ