add some figures, use different exaggeration algorithm

Makefile

@@ -40,7 +40,8 @@ RIVERS = \
 		 salvis-visvalingam-64-chaikin-50k \
 		 salvis-overlaid-douglas-64-chaikin-50k \
 		 salvis-overlaid-visvalingam-64-chaikin-50k \
-		 salvis-wm-24-50k
+		 salvis-wm-75-50k \
+		 salvis-wm-375-250k
 
 #################################
 # The thesis, publishable version
@@ -192,10 +193,15 @@ 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-24-50k_1SELECT = wm_visuals where name='salvis'
-salvis-wm-24-50k_2SELECT = wm_visuals where name='salvis-wm-24'
-salvis-wm-24-50k_2COLOR = orange
-#salvis-wm-24-50k_WIDTHDIV = 4
+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-375-250k_1SELECT = wm_visuals where name='salvis'
+salvis-wm-375-250k_2SELECT = wm_visuals where name='salvis-wm-375'
+salvis-wm-375-250k_1COLOR = orange
+salvis-wm-375-250k_WIDTHDIV = 2
 
 .faux_db: db init.sql rivers.sql
 	bash db start

mj-msc.tex

@@ -1292,18 +1292,25 @@ NOTE: this should provide a higher-level overview of the written code:
 
 \subsection{Generalization results of Analyzed Rivers}
 
-Figure~\ref{fig:salvis-wm-24-50k} visualizes the generalization result for
+Figure~\ref{fig:salvis-wm-75-50k} visualizes the generalization result for
 Šalčia and Visinčia. The generalized feature is orange. As can be seen,
 some isolated bends are exaggerated, and some small bends are removed.
 
-% TODO: replace 24 to 75.
 \begin{figure}[ht]
     \centering
-    \includegraphics[width=.5\textwidth]{salvis-wm-24-50k}
+    \includegraphics[width=.5\textwidth]{salvis-wm-75-50k}
     \caption{{\WM}-generalized river (1:{\numprint{50000}}).}
-    \label{fig:salvis-wm-24-50k}
+    \label{fig:salvis-wm-75-50k}
 \end{figure}
 
+\begin{figure}[ht]
+    \centering
+    \includegraphics[width=.5\textwidth]{salvis-wm-375-250k}
+    \caption{{\WM}-generalized river (1:{\numprint{250000}}).}
+    \label{fig:salvis-wm-375-250k}
+\end{figure}
+
+
 \subsection{Generalization result comparison with national spatial data sets}
 
 % TODO: GDR50LT and GDR250LT

test.sql

@@ -49,6 +49,8 @@ insert into wm_figures (name, way) values ('fig6-combi', ST_Union(
 insert into wm_figures (name, way) values ('selfcrossing-1-rev',ST_Reverse(
     ST_Translate((select way from wm_figures where name='selfcrossing-1'), 0, 60)));
 
+update wm_figures set way=st_setsrid(way, 3857);
+
 delete from wm_debug where name in (select distinct name from wm_figures);
 delete from wm_demo where name in (select distinct name from wm_figures);
 insert into wm_demo (name, way) select name, ST_SimplifyWM(way, .1, null, name) from wm_figures where name not in ('fig8', 'isolated-1');

visuals.sql

@@ -123,8 +123,7 @@ begin
       ('salvis-visvalingam-' || i, geom2),
       ('salvis-visvalingam-' || i || '-chaikin', st_chaikinsmoothing(geom2, 5));
   end loop;
-  -- TODO: 75
-  foreach i in array array[16, 24] loop
+  foreach i in array array[75, 375] loop
     geom3 = st_simplifywm((select way from wm_visuals where name='salvis'), i, 50, 'salvis-' || i);
     insert into wm_visuals(name, way) values
       ('salvis-wm-'          || i, geom3);

wm.sql

@@ -414,9 +414,9 @@ begin
   return st_split(st_snap(input, blade, 0.00000001), blade);
 end $$ language plpgsql;
 
--- wm_exaggerate_bend exaggerates a given bend. Must be a simple linestring.
-drop function if exists wm_exaggerate_bend;
-create function wm_exaggerate_bend(
+
+drop function if exists wm_exaggerate_bend2;
+create function wm_exaggerate_bend2(
   INOUT bend geometry,
   size float,
   desired_size float
@@ -424,9 +424,13 @@ create function wm_exaggerate_bend(
 declare
   scale constant float default 1.2; -- exaggeration enthusiasm
   midpoint geometry; -- midpoint of the baseline
-  splitbend geometry; -- bend split across its half
-  bendm geometry; -- bend with coefficients to prolong the lines
   points geometry[];
+  startazimuth float;
+  azimuth float;
+  diffazimuth float;
+  point geometry;
+  sss float;
+  protect int = 10;
 begin
   if size = 0 then
     raise 'invalid input: zero-area bend';
@@ -435,35 +439,36 @@ begin
       st_pointn(bend, 1),
       st_pointn(bend, -1)
     ), .5);
+  startazimuth = st_azimuth(midpoint, st_pointn(bend, 1));
 
-  while size < desired_size loop
-    splitbend = wm_st_split(bend, st_lineinterpolatepoint(bend, .5));
-    -- Convert bend to LINESTRINGM, where M is the fraction by how
-    -- much the point will be prolonged:
-    -- 1. draw a line between midpoint and the point on the bend.
-    -- 2. multiply the line length by M. Midpoint stays intact.
-    -- 3. the new set of lines form a new bend.
-    -- Uses linear interpolation; can be updated to gaussian or similar;
-    -- then interpolate manually instead of relying on st_addmeasure.
-    bendm = st_collect(
-      st_addmeasure(st_geometryn(splitbend, 1), 1, scale),
-      st_addmeasure(st_geometryn(splitbend, 2), scale, 1)
-    );
-
-    points = array((
-        select st_scale(
-          st_makepoint(st_x(geom), st_y(geom)),
-          st_makepoint(st_m(geom), st_m(geom)),
-          midpoint
-        )
-        from st_dumppoints(bendm)
-        order by path[1], path[2]
-      ));
-
-    bend = st_setsrid(st_makeline(points), st_srid(bend));
+  while (size < desired_size) and (protect > 0) loop
+    protect = protect - 1;
+    for i in 2..st_npoints(bend)-1 loop
+      point = st_pointn(bend, i);
+      azimuth = st_azimuth(midpoint, point);
+      diffazimuth = degrees(azimuth - startazimuth);
+      if diffazimuth > 180 then
+        diffazimuth = diffazimuth - 360;
+      elseif diffazimuth < -180 then
+        diffazimuth = diffazimuth + 360;
+      end if;
+      diffazimuth = abs(diffazimuth);
+      if diffazimuth > 90 then
+        diffazimuth = 180 - diffazimuth;
+      end if;
+      sss = ((scale-1) * (diffazimuth / 90)^0.5);
+      point = st_transform(
+        st_project(
+          st_transform(point, 4326)::geography,
+          st_distance(midpoint, point) * sss, azimuth)::geometry,
+        3857
+      );
+      bend = st_setpoint(bend, i-1, point);
+    end loop;
     size = wm_adjsize(bend);
   end loop;
-end $$ language plpgsql;
+end
+$$ language plpgsql;
 
 -- wm_adjsize calculates adjusted size for a polygon. Can return 0.
 drop function if exists wm_adjsize;
@@ -512,7 +517,7 @@ begin
   <<bendloop>>
   for i in 1..array_length(attrs, 1) loop
     if attrs[i].isolated and attrs[i].adjsize < desired_size then
-      bend = wm_exaggerate_bend(bends[i], attrs[i].adjsize, desired_size);
+      bend = wm_exaggerate_bend2(bends[i], attrs[i].adjsize, desired_size);
 
       -- does bend intersect with the previous or next
       -- intersect_patience bends? If they do, abort exaggeration for this one.