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Add mapping application
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‎examples/mapping.ipynb‎

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{
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"cells": [
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"from math import pow, cos, pi, radians, degrees, atan, tan, sinh, log\n",
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"from ipywidgets import Image, Output, IntSlider\n",
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"from ipycanvas import Canvas, MultiCanvas"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"def numTiles(z):\n",
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" return pow(2, z)\n",
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"\n",
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"def sec(x):\n",
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" return 1 / cos(x)\n",
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"\n",
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"def latlon2relativeXY(lat, lon):\n",
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" x = (lon + 180) / 360\n",
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" y = (1 - log(tan(radians(lat)) + sec(radians(lat))) / pi) / 2\n",
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" return x,y\n",
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"\n",
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"def latlon2xy(lat, lon, z):\n",
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" n = numTiles(z)\n",
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" x, y = latlon2relativeXY(lat, lon)\n",
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" return n * x, n * y\n",
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" \n",
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"def tileXY(lat, lon, z):\n",
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" x, y = latlon2xy(lat, lon, z)\n",
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" return int(x), int(y)\n",
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"\n",
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"def xy2latlon(x, y, z):\n",
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" n = numTiles(z)\n",
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" relY = y / n\n",
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" lat = mercatorToLat(pi * (1 - 2 * relY))\n",
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" lon = -180 + 360 * x / n\n",
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" return lat, lon\n",
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"\n",
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"def mercatorToLat(mercatorY):\n",
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" return degrees(atan(sinh(mercatorY)))"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"def get_tile_grid(x, y, width, height, ntiles):\n",
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" def get_indices(x, width, ntiles):\n",
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" def _(x, width, p, ntiles, xs=None, ns=None):\n",
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" '''p == 0: backward\n",
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" p == 1: forward\n",
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" Must be called with p=0 then p=1\n",
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" '''\n",
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" x2 = (x % 1) * 256\n",
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" if p == 0:\n",
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" xs = [width / 2 - x2]\n",
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" ns = [int(x)]\n",
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" else:\n",
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" x2 = 256 - x2\n",
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" done = False\n",
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" while not done:\n",
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" if x2 >= width / 2:\n",
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" # out of canvas, don't show next tile\n",
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" done = True\n",
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" else:\n",
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" # show (part of) next tile\n",
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" x2 += 256\n",
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" if p == 0:\n",
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" n1 = ns[-1] - 1\n",
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" x1 = xs[-1] - 256\n",
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" if n1 < 0:\n",
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" done = True\n",
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" else:\n",
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" ns.append(n1)\n",
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" xs.append(x1)\n",
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" else:\n",
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" n1 = ns[-1] + 1\n",
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" x1 = xs[-1] + 256\n",
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" if n1 >= ntiles:\n",
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" done = True\n",
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" else:\n",
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" ns.append(n1)\n",
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" xs.append(x1)\n",
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" if p == 0:\n",
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" xs = xs[::-1]\n",
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" ns = ns[::-1]\n",
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" return xs, ns\n",
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" xs, ns = _(x, width, 0, ntiles)\n",
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" xs, ns = _(x, width, 1, ntiles, xs, ns)\n",
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" return xs, ns\n",
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" xs, xn = get_indices(x, width, ntiles)\n",
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" ys, yn = get_indices(y, height, ntiles)\n",
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" def get_grid(xs, ys):\n",
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" xys = []\n",
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" for j in ys:\n",
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" xys.append([])\n",
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" for i in xs:\n",
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" xys[-1].append((i, j))\n",
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" return xys\n",
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" xys = get_grid(xs, ys)\n",
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" xyn = get_grid(xn, yn)\n",
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" return {'pix': xys, 'tile': xyn}"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"out = Output(layout={'border': '1px solid black'})"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"class Map(MultiCanvas):\n",
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" def __init__(self, height=256, width=256, zoom=0, lat=0, lon=0):\n",
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" super(Map, self).__init__(2, size=(height, width))\n",
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" \n",
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" self.z = zoom\n",
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" self.tile_nb = numTiles(zoom)\n",
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" self.height = height\n",
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" self.width = width\n",
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" self.dragging = False\n",
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" self.lat = lat\n",
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" self.lon = lon\n",
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" self.x, self.y = latlon2xy(lat, lon, zoom)\n",
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" \n",
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" self.show(lat, lon)\n",
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" \n",
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" self[1].on_mouse_down(self.mouse_down_handler)\n",
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" self[1].on_mouse_move(self.mouse_move_handler)\n",
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" self[1].on_mouse_up(self.mouse_up_handler)\n",
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" self[1].on_mouse_out(self.mouse_out_handler)\n",
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" \n",
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" #@out.capture()\n",
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" def show(self, lat=None, lon=None):\n",
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" if lat is None:\n",
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" lat = self.lat\n",
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" if lon is None:\n",
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" lon = self.lon\n",
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" x, y = latlon2xy(lat, lon, self.z)\n",
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" grid = get_tile_grid(x, y, self.width, self.height, self.tile_nb)\n",
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" for i, row in enumerate(grid['pix']):\n",
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" for j, col in enumerate(row):\n",
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" dx, dy = col\n",
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" x, y = grid['tile'][i][j]\n",
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" url = f'https://tile.openstreetmap.org/{self.z}/{x}/{y}.png'\n",
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" tile = Image.from_url(url)\n",
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" self[0].draw_image(tile, dx, dy)\n",
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" def mouse_down_handler(self, pixel_x, pixel_y):\n",
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" self.dragging = True\n",
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" self.x_mouse = pixel_x\n",
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" self.y_mouse = pixel_y\n",
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" \n",
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" def mouse_move_handler(self, pixel_x, pixel_y):\n",
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" if self.dragging:\n",
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" x, y, lat, lon = self.delta(pixel_x, pixel_y)\n",
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" self.show(lat, lon)\n",
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" \n",
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" def delta(self, pixel_x, pixel_y):\n",
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" dx = (pixel_x - self.x_mouse) / 256\n",
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" dy = (pixel_y - self.y_mouse) / 256\n",
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" x = self.x - dx\n",
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" y = self.y - dy\n",
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" lat, lon = xy2latlon(x, y, self.z)\n",
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" return x, y, lat, lon\n",
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" \n",
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" def mouse_up_handler(self, pixel_x, pixel_y):\n",
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" self.dragging = False\n",
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" self.x, self.y, self.lat, self.lon = self.delta(pixel_x, pixel_y)\n",
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" self.show()\n",
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" \n",
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" def mouse_out_handler(self, pixel_x, pixel_y):\n",
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" self.dragging = False"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"m = Map(788, 788, 7, 49, 2)\n",
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"m"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"slider = IntSlider(description='Zoom:', value=m.z, min=3, max=10, step=1)\n",
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"\n",
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"def on_slider_change(change):\n",
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" m.z = slider.value\n",
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" m.tile_nb = numTiles(m.z)\n",
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" m.x, m.y = latlon2xy(m.lat, m.lon, m.z)\n",
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" m.show()\n",
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"\n",
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"slider.observe(on_slider_change, 'value')\n",
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"slider"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"out"
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.7.3"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 2
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}

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