add gpkg samples

.gitignore

@@ -18,6 +18,10 @@ __pycache__
 *.blg
 *.bcf
 *.run.xml
+*.gpkg-wal
+*.gpkg-shm
 
 env/
 *.pyc
+version.tex
+db/

II/Referatas/Makefile

@@ -1,2 +1,30 @@
-mj-referatas.pdf: $(shell git ls-files .)
-	latexmk -g -pdf mj-referatas.tex
+SHELL = /bin/bash
+
+GEN = zeimena.pdf st-simplify-100.pdf st-simplify-150.pdf st-simplify-300.pdf st-simplify-500.pdf
+
+mj-referatas.pdf: mj-referatas.tex version.tex bib.bib zeimena-pretty.pdf $(GEN)
+	latexmk -g -pdf $<
+
+zeimena.pdf: zeimena.gpkg
+	./layer2img.py --infile=$< --size=74x52 --outfile $@
+
+st-simplify-%.pdf: db/.faux_st-simplify-%
+	./layer2img.py --table=douglas_$* --size=74x52 --outfile $@
+
+db/.faux_st-simplify-%: db/.faux_ready st-simplify.sql
+	. ./managedb ; \
+		psql --echo-all -v ON_ERROR_STOP=1 -v tolerance=$* -f st-simplify.sql
+	touch $@
+
+db/.faux_ready: zeimena.gpkg managedb
+	-./managedb stop; rm -fr db
+	./managedb init
+	ogr2ogr -f PostgreSQL "PG:host=127.0.0.1 user=osm dbname=osm" zeimena.gpkg
+	touch $@
+
+GIT_DIR = $(shell git rev-parse --show-toplevel)/.git
+
+version.tex: $(shell git ls-files .) $(GIT_DIR)
+	date "+%F %T %Z" | awk '{print "\\gdef\\GeneratedAt{"$$0"}%"}' > $@
+	[ -n "$$(git status --porcelain)" ] && suffix="-dirty"; \
+		git describe --tags | awk '{print "\\gdef\\VCDescribe{"$$0"'$$suffix'}%"}' >> $@

II/Referatas/bib.bib

@@ -52,7 +52,7 @@
   publisher={University of Toronto Press}
 }
 
-// algorithms for generalization, not reaching satisfactory results
+% Algorithms for generalization, not reaching satisfactory results
 @inproceedings{monmonier1986toward,
   title={Toward a practicable model of cartographic generalisation.},
   author={Monmonier, Mark},
@@ -113,7 +113,7 @@
   year={2012}
 }
 
-// LIKELY UNNEEDED
+% LIKELY UNNEEDED
 @book{buttenfield1991map,
   title={Map Generalization: Making rules for knowledge representation},
   author={Buttenfield, Barbara Pfeil and McMaster, Robert Brainerd},

II/Referatas/layer2img.py

@@ -3,12 +3,15 @@
 
 import argparse
 import geopandas
+import psycopg2
 import matplotlib.pyplot as plt
 
 INCH = 25.4  # mm
 
+
 def plt_size(string):
     if not string:
+        # using default matplotlib dimensions
         return None
     try:
         w, h = string.split("x")
@@ -16,25 +19,36 @@ def plt_size(string):
     except Exception as e:
         raise argparse.ArgumentTypeError from e
 
+
 def parse_args():
-    parser = argparse.ArgumentParser(description='Convert layer to an image')
-    parser.add_argument('infile', type=str)
-    parser.add_argument('layer', type=str)
-    parser.add_argument('-o', '--output', metavar='<file>', type=str)
-    parser.add_argument('--size', type=plt_size, help='Figure size in mm (WWxHH)')
+    parser = argparse.ArgumentParser(
+            description='Convert geopackage to an image')
+    group = parser.add_mutually_exclusive_group(required=True)
+    group.add_argument('--infile', type=str)
+    group.add_argument('--table', type=str)
+    parser.add_argument('-o', '--outfile', metavar='<file>', type=str)
+    parser.add_argument(
+            '--size', type=plt_size, help='Figure size in mm (WWxHH)')
     return parser.parse_args()
 
+
 def main():
     args = parse_args()
+    if args.table:
+        conn = psycopg2.connect("host=127.0.0.1 dbname=osm user=osm")
+        sql = "SELECT geom FROM %s" % args.table
+        f = geopandas.read_postgis(sql, con=conn, geom_col='geom')
+    else:
         f = geopandas.read_file(args.infile)
     f.plot(figsize=args.size)
     plt.axis('off')
     plt.margins(0, 0)
     plt.tight_layout(0)
-    if args.output:
-        plt.savefig(args.output, bbox_inches=0, dpi=300)
+    if args.outfile:
+        plt.savefig(args.outfile, bbox_inches=0, dpi=300)
     else:
         plt.show()
 
+
 if __name__ == '__main__':
     main()

II/Referatas/managedb

@@ -0,0 +1,46 @@
+#!/bin/bash
+
+main() {
+    PATH=$PATH:/usr/lib/postgresql/12/bin
+    case ${1:-} in
+        init)
+            mkdir -p db && initdb db
+            mkdir -p db/wal
+            sed -i "s/.*unix_socket_dir.*/unix_socket_directories = '.\/wal'/" \
+                db/postgresql.conf
+            pg_ctl -D db -l db/logfile start
+
+            export PGHOST=127.0.0.1
+            psql postgres -c 'CREATE ROLE osm WITH SUPERUSER LOGIN'
+            psql postgres -c 'CREATE DATABASE osm'
+            psql osm osm -c 'CREATE EXTENSION postgis'
+            ;;
+        start)
+            pg_ctl -D db -l db/logfile start
+            ;;
+        stop)
+            pg_ctl -D db -l db/logfile stop
+            ;;
+        *)
+            >&2 echo "Unknown command: '$*'"
+            exit 1
+            ;;
+    esac
+}
+
+if [[ "${BASH_SOURCE[0]}" != "${0}" ]]; then
+    if [[ $# != 0 ]]; then
+        >&2 echo "Sourcing does not accept arguments: $*"
+    else
+        export PGHOST=127.0.0.1
+        export PGUSER=osm
+        export PGDATABASE=osm
+        >&2 echo "OK: exported PGUSER, PGHOST and PGDATABASE"
+    fi
+else
+    set -euo pipefail
+    export PGHOST=
+    export PGUSER=
+    export PGDATABASE=
+    main "$@"
+fi

II/Referatas/mj-referatas.tex

@@ -14,6 +14,7 @@
 \usepackage{varwidth}
 \usepackage{tikz}
 \usetikzlibrary{er,positioning}
+\input{version}
 
 \title{
     Cartografic Generalization of Lines \\
@@ -21,15 +22,40 @@
 }
 
 \iffalse
+small scale: 1:XXXXXX
+large scale: 1:XXX
+
+take douglas-pecker and check for different scales.
+
 a4: 210x297mm
 a6: 105x148xmm
 a7: 74x105mm
 a8: 52x74mm
+
+connect rivers first to a single polylines:
+- some algs can preserve connectivity, some not.
+
+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}
 
-\date{\today}
+\date{
+    \vspace{10mm}
+    Version: \VCDescribe \\ \vspace{4mm}
+    Generated At: \GeneratedAt
+}
 
 \begin{document}
 \maketitle
@@ -73,7 +99,7 @@ of straight and curved river shape, and author's familiarity with the location.
 
 \begin{figure}
     \centering
-    \includegraphics[width=148mm]{zeimena}
+    \includegraphics[width=148mm]{zeimena-pretty}
     \caption{Žeimena near Jaunadaris}
     \label{fig:zeimena}
 \end{figure}
@@ -81,19 +107,60 @@ of straight and curved river shape, and author's familiarity with the location.
 \section{Mathematical and geometrical algorithms}
 
 To understand why geometrical algorithms are not entirely suitable for 
-downscaling, let's pick some visual examples.
+downscaling, let's pick some visual examples. Start with
+\cite{douglas1973algorithms}, one of the most well-known line simplification
+algorithms, which is often used for generalization. Žeimena example is
+generalized with different tolerances in figure~\ref{fig:douglas-peucker} on
+page~\pageref{fig:douglas-peucker}.
 
-\subsection{Douglas \& Peucker}
+As one can observe in figure~\ref{fig:douglas-100}, the Douglas \& Peucker with
+100m tolerance preserves most of the shape, and 500m
+(figure~\ref{fig:douglas-500}) becomes a straight line.
 
-\cite{douglas1973algorithms} is one of the most well-known line simplification
-algorithms, which is often used for generalization. It will simplify the line shape.
-
-Trying the same dataset with different tolerances for Douglas \& Peucker.
+\begin{figure}
+    \centering
+    \begin{subfigure}[b]{0.18\textwidth}
+        \includegraphics[width=\textwidth]{zeimena}
+        \caption{original}
+        \label{fig:zeimena-original}
+    \end{subfigure}
+    ~
+    \begin{subfigure}[b]{0.18\textwidth}
+        \includegraphics[width=\textwidth]{st-simplify-100}
+        \caption{100m}
+        \label{fig:douglas-100}
+    \end{subfigure}
+    ~
+    \begin{subfigure}[b]{0.18\textwidth}
+        \includegraphics[width=\textwidth]{st-simplify-150}
+        \caption{150m}
+        \label{fig:douglas-150}
+    \end{subfigure}
+    ~
+    \begin{subfigure}[b]{0.18\textwidth}
+        \includegraphics[width=\textwidth]{st-simplify-300}
+        \caption{300m}
+        \label{fig:douglas-300}
+    \end{subfigure}
+    ~
+    \begin{subfigure}[b]{0.18\textwidth}
+        \includegraphics[width=\textwidth]{st-simplify-500}
+        \caption{500m}
+        \label{fig:douglas-500}
+    \end{subfigure}
+    \caption{Douglas \& Peucker line simplifications with different tolerances}
+    \label{fig:douglas-peucker}
+\end{figure}
 
 \section{Algorithms based on cartographical knowledge}
 
-\cite{jiang2003line}, \cite{dyken2009simultaneous},
-\cite{mustafa2006dynamic}, \cite{nollenburg2008morphing}
+For further investigation:
+\begin{itemize}
+    \item \cite{jiang2003line}
+    \item \cite{dyken2009simultaneous}
+    \item \cite{mustafa2006dynamic}
+    \item \cite{nollenburg2008morphing}
+\end{itemize}
 
 \section{My Idea}
 \label{sec:my_idea}

II/Referatas/st-simplify.sql

@@ -0,0 +1,14 @@
+DROP TABLE IF EXISTS douglas_:tolerance;
+
+CREATE TABLE douglas_:tolerance (
+    fid serial NOT NULL,
+    geom geometry(MULTILINESTRING, 3346)
+);
+
+INSERT INTO douglas_:tolerance (geom) (
+    SELECT
+        ST_Simplify (ST_LineMerge (ST_Union (geom)),
+            :tolerance) AS geoms
+    FROM
+        zeimena);
+