From e8cf66ebb95a0aa598ae0090d4f5f5a1e28a2897 Mon Sep 17 00:00:00 2001
From: nathan <nathan.matsuda@gmail.com>
Date: Tue, 16 Jun 2020 18:10:25 -0700
Subject: [PATCH] added resolution argument to mapconverter

Former-commit-id: 0f330b65175f27f4662c8eb56ff7eef105f97ac0
---
 README.md       | 22 ++++++++++++++++++----
 mapconverter.py | 15 +++++++++++----
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index b5924b9..2651338 100644
--- a/README.md
+++ b/README.md
@@ -10,12 +10,12 @@ There are a lot of missing pieces in this implementation so far:
 
 ### BUILDING
 
-Tested and working on Ubuntu 18.04, Raspbian Stretch / Buster, Windows Subsystem for Linux (with Ubuntu 18.04)
+Tested and working on Ubuntu 18.04, Raspbian Stretch / Buster, Windows Subsystem for Linux (with Ubuntu 18.04), and Mac
 
 0. Install build essentials
 
 ```
-sudo apt-get install build-essentials
+sudo apt-get install build-essential
 ```
 
 1. Install SDL and RTL-SDR libararies
@@ -43,7 +43,21 @@ pip3 install lxml numpy tqdm
 ./getmap.sh
 ```
 
-3. (optional for Windows)
+The mapconverter script called by getmap.sh downsamples the file to render resonably quickly on a Raspberri Pi 4. If you are on a slower device (e.g, a Raspberry Pi 3), you may want to try something like:
+
+```
+python3 mapconverter.py --resolution 64 all.svg
+```
+
+On the other hand, if you are on a modern desktop or laptop, you can use something higher (but you probably don't need the full 6 digit precision of the McCurley SVG file):
+
+
+```
+python3 mapconverter.py --resolution 8192 all.svg
+```
+
+
+3. (Windows only)
 
 As WSL does not have an X server built in, you will need to install a 3rd party X server, such as https://sourceforge.net/projects/vcxsrv/
 
@@ -79,7 +93,7 @@ viz1090 will open an SDL window set to the resolution of your screen.
 | --metric						| Display metric units | 
 | --lat                         | Specify your latitude in degrees | 
 | --lon                         | Specify your longitiude in degrees | 
-| --screensize [width] [height]	| Specify a specific resolution to pass to SDL_RenderSetLogicalSize, otherwise use resolution of display | 
+| --screensize [width] [height]	| Specify a resolution, otherwise use resolution of display | 
 | --uiscale [scale]				| Scale up UI elements by integer amounts for high resolution screen | 
 | --fullscreen					| Render fullscreen rather than in a window | 
 
diff --git a/mapconverter.py b/mapconverter.py
index 4b807ff..63f707f 100644
--- a/mapconverter.py
+++ b/mapconverter.py
@@ -2,15 +2,21 @@ from lxml import etree as ElementTree
 import numpy as np
 import sys
 from tqdm import tqdm 
+import argparse
 
-filename = sys.argv[1]
+parser = argparse.ArgumentParser(description='viz1090 SVG Map Converter')
+parser.add_argument("--resolution", default=250, type=int, nargs=1, help="downsample resolution")
+parser.add_argument("file", nargs=1, help="filename")
 
-if(len(filename) == 0):
+args = parser.parse_args()
+
+
+if(len(args.file) == 0):
 	print("No input filename given")
 	exit()
 
 parser = ElementTree.XMLParser(recover=True)
-tree = ElementTree.parse(filename, parser)
+tree = ElementTree.parse(args.file[0], parser)
 polys = tree.xpath('//polygon')
 
 bin_file = open("mapdata.bin", "wb")
@@ -18,7 +24,8 @@ bin_file = open("mapdata.bin", "wb")
 outlist = []
 
 
-resolution = 250
+resolution = args.resolution[0]
+
 print("Reading points")
 for i in tqdm(range(len(polys))):
 #for i in range(40):