Rendering a map from terrarium height map tiles and exporting to 16 bit grayscale PNG

README.md

Convert tangram tiles to 16 bit grayscale PNG

Requirements

• PHP >7.2
  • Composer
• Python3
  • numpy
  • cupy (optional)
  • PIL

Installation

composer install

Usage

For all options use

php renderLocation.php --help

Example command

php renderLocation.php -a YOUR_API_KEY --latitude 12.345 --longitude 123.456 --zoom 15 -x 5 -y 5 -e

Examples

The examples in this gist are generated using the following command:

php renderLocation.php -a YOUR_API_KEY -l 36.6271 -k 138.20453 -x 8 -y 8 -z 13 -e

On my XPS 15 9350 with i7 and 32GB ram, aside from downloading, the process takes around 15s to complete for this example.

combineImages.py

import time
import cupy as cp
import numpy as np
import sys
from os import path
from PIL import Image
Image.MAX_IMAGE_PIXELS = 300000*300000

if len(sys.argv) < 8:
    raise ValueError('Should be 7 arguments')

x1 = int(sys.argv[1])
x2 = x1+int(sys.argv[2])
y1 = int(sys.argv[3])
y2 = y1+int(sys.argv[4])
z  = int(sys.argv[5])
ss = int(sys.argv[6]) # square size
nfn = sys.argv[7]

newIm = Image.new('RGB', (ss * abs(x2-x1), ss * abs(y2-y1)))
for x in range(x1, x2, 1):
    print('Reading row {}'.format(abs(x-x1)))
    for y in range(y1, y2, 1):
        fn = 'cache/{}-{}-{}.png'.format(z,y,x)
        im = Image.open(fn)
        newIm.paste(im, (abs((y-y1))*ss, abs((x-x1))*ss))

print('Done reading, now writing')
newIm.save(nfn)
print('Done!')

composer.json

{
    "require": {
        "guzzlehttp/guzzle": "7.0",
        "league/climate": "^3.8",
        "nategood/commando": "^0.4.0",
        "symfony/process": "^5.4"
    }
}

convertTo16BitCpu.py

import time
import cupy as cp
import numpy as np
import sys
from os import path
from PIL import Image
Image.MAX_IMAGE_PIXELS = 300000*300000

if len(sys.argv) < 2:
    raise ValueError('No file argument given')

fn = sys.argv[1]

if not path.exists(fn):
    raise ValueError('File {} does not exist'.format(fn))

usecupy = False

nfn = '{}-gs-norm-{}.png'.format(path.splitext(fn)[0], 'cupy' if usecupy else 'numpy')

if path.exists(nfn):
    raise ValueError('File {} already exists'.format(nfn))

factor = 2**8
rangef = 2**15
rangem = 2**16

step = 6
barwidth = 40
barchar1 = '#'
barchar2 = ' '
start = time.time()
print('Reading image - will write to {}'.format(nfn))
with Image.open(fn) as src:
    if usecupy:
        print('{} GPU devices found'.format(cp.cuda.runtime.getDeviceCount()))
        with cp.cuda.Device(0) as dev0:
            dev0.use()
            print('Compute Capability {}'.format(dev0.compute_capability))
            cparray = cp.asarray(src, dtype='uint8')
            print('Image read')
            cparray = cparray.dot(cp.array([factor,1,1/factor], dtype='float32'))
            cparray = cp.subtract(cparray, rangef, dtype='float32')
            maxv = cp.amax(cparray)
            minv = cp.amin(cparray)
            rangev = maxv - minv
            cparray = cp.subtract(cparray, minv)
            cparray = cp.multiply(cparray, rangem/(maxv - minv))
            dest = Image.fromarray(cp.asnumpy(cparray).astype('uint16'), 'I;16')
            print('Writing image - Size {}x{} - mode {}'.format(dest.width, dest.height, dest.mode))
            dest.save(nfn)
    else:
        nparray = np.asarray(src, dtype='uint8')
        print('Image read')
        nparray = nparray.dot(np.array([factor,1,1/factor], dtype='float32'))
        nparray = np.subtract(nparray, rangef, dtype='float32')
        maxv = np.amax(nparray)
        minv = np.amin(nparray)
        rangev = maxv - minv
        nparray = np.subtract(nparray, minv, dtype='float32')
        nparray = np.multiply(nparray, rangem/(maxv - minv)).astype('uint16')
        dest = Image.fromarray(nparray, 'I;16')
        print('Writing image - Size {}x{} - mode {}'.format(dest.width, dest.height, dest.mode))
        dest.save(nfn)
    print('Complete - took {:.1f}s'.format(time.time() - start))

example_output_grayscale.png

example_output_rgb.png

renderLocation.php

Hi! I would like to say a big thank you for this app and the web interface for it. It's really cool stuff! This web application simplifies my work so much.

My pleasure!