From 2341bf83d5da70fc9d64ee529619905187e15973 Mon Sep 17 00:00:00 2001
From: Andrew Lorimer <andrew@lorimer.id.au>
Date: Tue, 14 Jun 2022 15:46:59 +1000
Subject: [PATCH] add zoom level argument to vicmap-montage.sh

---
 vicmap-montage.sh | 40 ++++++++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/vicmap-montage.sh b/vicmap-montage.sh
index 44ea6c6..12b760b 100755
--- a/vicmap-montage.sh
+++ b/vicmap-montage.sh
@@ -2,13 +2,13 @@
 
 # Tool for downloading Vicmap Basemap aerial photography (provided as tiles)
 # and combine into a single file. View maps and determine desired coordinates
-# here - https://services.land.vic.gov.au/DELWPmaps/historical-photomaps/
+# here - https://mapshare.vic.gov.au/webmap/historical-photomaps/
 # (turn on "Vicmap Basemap - Aerial")
 
 # Andrew Lorimer - April 2021
 
 usagelong="\e[1mUSAGE:\e[0m
-  $(basename "$0") LONGMIN LONGMAX LATMIN LATMAX [OUTPUT]
+  $(basename "$0") LONGMIN LONGMAX LATMIN LATMAX [[ZOOM] OUTPUT]
 
 \e[1mOPTIONS:\e[0m
   LONGMIN
@@ -23,30 +23,39 @@ usagelong="\e[1mUSAGE:\e[0m
   LATMAX
     Maximum latitude
 
+  ZOOM
+    The zoom level for tiles, 1-20. Zoom 5 captures the whole state in one 
+    512x512px tile. Zoom 20 produces 62.44m square tiles at 512x512px. Note 
+    coordinates change between zoom levels - the coordinates for the north west 
+    corner of each tile are multiplied by two for each increment in zoom level. 
+    This accounts for each tile splitting into 4 (i.e. doubling the scale).
+    Default: 20
+
   OUTPUT
-    Name of file to output to (relative to current directory). Default: vicmap.png
+    Name of file to output to (relative to current directory).
+    Default: vicmap.png
  
   Inspect Element on map, then find the <div> with the satellite images (element 
-  id varies). The second last number in each image URL corresponds to the longitude 
-  (E-W) and the last number corresponds to the latitude (N-S). Find the maximum 
-  latitude and longitude in the range shown.\n"
-
-longmin=473737
-longmax=473741
-latmin=321805
-latmax=321808
-output="vicmap.png"
+  id typically OpenLayers_Layer_XYZ_8). The second last number in each image 
+  URL corresponds to the longitude (E-W) and the last number corresponds to the 
+  latitude (N-S). Find the maximum latitude and longitude in the range shown.\n"
 
-if (( $# < 4 || $# > 5)); then
+if (( $# < 4 || $# > 6)); then
   printf "$usagelong"
   exit
 fi
+zoom="20"
+output="vicmap.png"
+
 longmin=$1
 longmax=$2
 latmin=$3
 latmax=$4
 if (( $# == 5 )); then
   output=$5
+elif (( $# == 6)); then
+  zoom=$5
+  output=$6
 fi
 
 x=$(( $longmax - $longmin + 1))
@@ -55,18 +64,17 @@ y=$(( $latmax - $latmin + 1))
 mkdir -p .vicmap-tmp
 cd .vicmap-tmp
 
-i=$longmin
 # Iterate through longitudes (columns)
 for ((i=$longmin; i<=$longmax; i++)); do
   mkdir -p $i
   # Iterate through latitudes (individual tiles N to S)
   for ((j=$latmin; j<=$latmax; j++)); do
-    curl -s -C - https://base.maps.vic.gov.au/wmts/AERIAL_WM/EPSG:3857/20/$i/$j.png -o $i/$j.png
+    curl -s -C - https://base.maps.vic.gov.au/wmts/AERIAL_WM/EPSG:3857/$zoom/$i/$j.png -o $i/$j.png
   done
   montage $i/* -tile 1x"$y" -geometry +0+0 $i.png
 done
 
 montage *.png -tile "$x"x1 -geometry +0+0 ../$output
 
-
+cd ..
 rm -rf .vicmap-tmp
-- 
2.47.0