Lua oop middleclass spawn enemies with random x coordinate - oop

I make a game with lua/LÖVE and i use the middleclass library for OOP, but i have a problem, my game is a space shooter game with a base class "entity" a subclass "player" and "meteor" (enemy that fall from the top of the screen with a random x coordinate) but i don't know how to make the random spawn system for the meteor (a random x coordinate).
Entity = class('Entity')
function Entity:initialize(x, y, width, height, image)
self.x = x
self.y = y
self.width = width
self.height = height
self.image = image
end
function Entity:draw()
love.graphics.draw(self.image, self.x, self.y)
end
meteor.lua = https://pastebin.com/9WLENrLN gameState.lua = https://pastebin.com/p0fH1XmN
(the game file)
Everytimes that i launch the game, the x coordinate of the meteor object is the same, i want to spawn one meteor with a random x coordinate every 2 seconds, but i don't know how to do that. I think that i've made something wrong but i don't know. :/
function Meteor:initialize()
self.speed = 400
meteorWidth = 45
meteorHeight = 40
self.x = love.math.random(0, WINDOW_WIDHT - meteorWidth)
meteorY = 0 - meteorWidth
Entity.initialize(self, self.x, meteorY, 64, 64, love.graphics.newImage('assets/meteor.png'))
end
After that i would like also to delete the object when it is outside of the screen. I know how to do that without oop but with oop i'm stuck...
Thanks you in advance !
How should i create the random spawn system ? Should i create many objects meteor from the meteor class blueprint inside the gameState.lua file ?

Related

I'm making a code with pygame in oop and I'm having trouble making one of my methods work

Basically, I am making a code that uses oop and pygame together. It draws 4 rectangles in the corners of the screen and gives each rectangle a name. I have to ask the user the name of one of the rectangles and change that rectangles color randomly.
Code:
import random
import pygame
from pygame.locals import *
pygame.init()
screen = pygame.display.set_mode((500,500))
pygame.display.set_caption("BOOGABOOGA")
blue = (0,0,255)
red = (255,0,0)
green = (0,255,0)
white = (255,255,255)
random = [blue,red,green,white]
class Rectangle:
def __init__(self,name,color,x,y,width,height,thickness):
self.name = name
self.color = color
self.x = x
self.y = y
self.width = width
self.height = height
self.thickness = thickness
def coolboymethoddraw(self):
pygame.draw.rect(screen,self.color,(self.x,self.y,self.width,self.height),self.thickness)
recty1 = Rectangle("YOYO",blue,50,50,50,50,0)
recty2 = Rectangle("BABYBOOGA",blue,450,450,50,50,0)
recty3 = Rectangle("ChotaBEAM",blue,0,450,50,50,0)
recty4 = Rectangle("CHOTAJAGGU",blue,450,0,50,50,0)
jaggu = [recty1,recty2,recty3,recty4]
recty3.coolboymethoddraw()
recty1.coolboymethoddraw()
recty4.coolboymethoddraw()
recty2.coolboymethoddraw()
def change_color(self):
print("Give me the name of 1 of the 4 rectangles!")
x = input()
for chota in jaggu:
if x == chota.name:
l = random.choice(random)
chota.color = l
recty1.change_color()
recty2.changecolor()
recty3.change_color()
recty4.change_color()
while True:
for event in pygame.event.get():
if event.type == QUIT:
pygame.quit()
exit()
pygame.display.update()
I would appreciate an answer and why it wasn't working. Thanks!
First of all move your method change_color inside the class Rectangle.
class Rectangle:
def __init__(self,name,color,x,y,width,height,thickness):
self.name = name
self.color = color
self.x = x
self.y = y
self.width = width
self.height = height
self.thickness = thickness
def coolboymethoddraw(self):
pygame.draw.rect(screen,self.color,(self.x,self.y,self.width,self.height),self.thickness)
def change_color(self):
print("Give me the name of 1 of the 4 rectangles!")
x = input()
for chota in jaggu:
if x == chota.name:
l = random.choice(random)
chota.color = l
Then you need to move the draw methods inside the main loop, otherwise the rectangles will not be drawn.
while True:
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
exit()
recty3.coolboymethoddraw()
recty1.coolboymethoddraw()
recty4.coolboymethoddraw()
recty2.coolboymethoddraw()
pygame.display.update()
Dont name your list of colors random because you import a package called random. Name the list something like colors_list
You dont need to call the change_color method for all 4 rectangles because inside of this method you go through a list of your 4 rectangles already.
There is also a problem in the change_color method. You need to call the method inside the main loop as well, but because of the print statement and the input it will end in an ifinite loop.

Stimuli changes with every frame being displayed.

I have a bit of code (displayed below) that is supposed to display the stimulus for 10 frames. We need pretty exact display times, so using number of frames is a must instead of core.wait(xx) as the display time won't be as precise.
Instead of drawing the stimuli, and leaving it for another 9 frames - the stimuli is re-drawn for every frame.
# Import what is needed
import numpy as np
from psychopy import visual, event, core, logging
from math import sin, cos
import random, math
win = visual.Window(size=(1366, 768), fullscr=True, screen=0, allowGUI=False, allowStencil=False,
monitor='testMonitor', color=[0,0,0], colorSpace='rgb',
blendMode='avg', useFBO=True,
units='deg')
### Definitions of libraries
'''Parameters :
numpy - python package of numerical computations
visual - where all visual stimulus live
event - code to deal with mouse + keyboard input
core - general function for timing & closing the program
logging - provides function for logging error and other messages to one file
random - options for creating arrays of random numbers
sin & cos - for geometry and trigonometry
math - mathematical operations '''
# this is supposed to record all frames
win.setRecordFrameIntervals(True)
win._refreshThreshold=1/65.0+0.004 #i've got 65Hz monitor and want to allow 4ms tolerance
#set the log module to report warnings to the std output window (default is errors only)
logging.console.setLevel(logging.WARNING)
nIntervals=5
# Create space variables and a window
lineSpaceX = 0.55
lineSpaceY = 0.55
patch_orientation = 45 # zero is vertical, going anti-clockwise
surround_orientation = 90
#Jitter values
g_posJitter = 0.05 #gaussian positional jitter
r_posJitter = 0.05 #random positional jitter
g_oriJitter = 5 #gaussian orientation jitter
r_oriJitter = 5 #random orientation jitter
#create a 1-Dimentional array
line = np.array(range(38)) #with values from (0-37) #possibly not needed 01/04/16 DK
#Region where the rectangular patch would appear
#x_rand=random.randint(1,22) #random.randint(Return random integers from low (inclusive) to high (exclusive).
#y_rand=random.randint(1,25)
x_rand=random.randint(6,13) #random.randint(Return random integers from low (inclusive) to high (inclusive).
y_rand=random.randint(6,16)
#rectangular patch dimensions
width=15
height=12
message = visual.TextStim(win,pos=(0.0,-12.0),text='...Press SPACE to continue...')
fixation = visual.TextStim(win, pos=(0.0,0.0), text='X')
# Initialize clock to record response time
rt_clock = core.Clock()
#Nested loop to draw anti-aliased lines on grid
#create a function for this
def myStim():
for x in xrange(1,33): #32x32 grid. When x is 33 will not execute loop - will stop
for y in xrange(1,33): #When y is 33 will not execute loop - will stop
##Define x & y value (Gaussian distribution-positional jitter)
x_pos = (x-32/2-1/2 )*lineSpaceX + random.gauss(0,g_posJitter) #random.gauss(mean,s.d); -1/2 is to center even-numbered stimuli; 32x32 grid
y_pos = (y-32/2-1/2 )*lineSpaceY + random.gauss(0,g_posJitter)
if (x >= x_rand and x < x_rand+width) and (y >= y_rand and y < y_rand+height): # note only "=" on one side
Line_Orientation = random.gauss(patch_orientation,g_oriJitter) #random.gauss(mean,s.d) - Gaussian func.
else:
Line_Orientation = random.gauss(surround_orientation,g_oriJitter) #random.gauss(mean,s.d) - Gaussian func.
#Line_Orientation = random.gauss(Line_Orientation,g_oriJitter) #random.gauss(mean,s.d) - Gaussian func.
#stimOri = random.uniform(xOri - r_oriJitter, xOri + r_oriJitter) #random.uniform(A,B) - Uniform func.
visual.Line(win, units = "deg", start=(0,0), end=(0.0,0.35), pos=(x_pos,y_pos), ori=Line_Orientation, autoLog=False).draw() #Gaussian func.
for frameN in range (10):
myStim()
win.flip()
print x_rand, y_rand
print keys, rt #display response and reaction time on screen output window
I have tried to use the following code to keep it displayed (by not clearing the buffer). But it just draws over it several times.
for frameN in range(10):
myStim()
win.flip(clearBuffer=False)
I realize that the problem could be because I have .draw() in the function that I have defined def myStim():. However, if I don't include the .draw() within the function - I won't be able to display the stimuli.
Thanks in advance for any help.
If I understand correctly, the problem you are facing is that you have to re-draw the stimulus on every flip, but your current drawing function also recreates the entire (random) stimulus, so:
the stimulus changes on each draw between flips, although you need it to stay constant, and
you get a (on some systems quite massive) performance penalty by re-creating the entire stimulus over and over again.
What you want instead is: create the stimulus once, in its entirety, before presentation; and then have this pre-generated stimulus drawn on every flip.
Since your stimulus consists of a fairly large number of visual elements, I would suggest using a class to store the stimulus in one place.
Essentially, you would replace your myStim() function with this class (note that I stripped out most comments, re-aligned the code a bit, and simplified the if statement):
class MyStim(object):
def __init__(self):
self.lines = []
for x in xrange(1, 33):
for y in xrange(1, 33):
x_pos = ((x - 32 / 2 - 1 / 2) * lineSpaceX +
random.gauss(0, g_posJitter))
y_pos = ((y - 32 / 2 - 1 / 2) * lineSpaceY +
random.gauss(0, g_posJitter))
if ((x_rand <= x < x_rand + width) and
(y_rand <= y < y_rand + height)):
Line_Orientation = random.gauss(patch_orientation,
g_oriJitter)
else:
Line_Orientation = random.gauss(surround_orientation,
g_oriJitter)
current_line = visual.Line(
win, units="deg", start=(0, 0), end=(0.0, 0.35),
pos=(x_pos, y_pos), ori=Line_Orientation,
autoLog=False
)
self.lines.append(current_line)
def draw(self):
[line.draw() for line in self.lines]
What this code does on instantiation is in principle identical to your myStim() function: it creates a set of (random) lines. But instead of drawing them onto the screen right away, they are all collected in the list self.lines, and will remain there until we actually need them.
The draw() method traverses through this list, element by element (that is, line by line), and calls every line's draw() method. Note that the stimuli do not have to be re-created every time we want to draw the whole set, but instead we just draw the already pre-created lines!
To get this working in practice, you first need to instantiate the MyStim class:
myStim = MyStim()
Then, whenever you want to present the stimulus, all you have to do is
myStim.draw()
win.flip()
Here is the entire, modified code that should get you started:
import numpy as np
from psychopy import visual, event, core, logging
from math import sin, cos
import random, math
win = visual.Window(size=(1366, 768), fullscr=True, screen=0, allowGUI=False, allowStencil=False,
monitor='testMonitor', color=[0,0,0], colorSpace='rgb',
blendMode='avg', useFBO=True,
units='deg')
# this is supposed to record all frames
win.setRecordFrameIntervals(True)
win._refreshThreshold=1/65.0+0.004 #i've got 65Hz monitor and want to allow 4ms tolerance
#set the log module to report warnings to the std output window (default is errors only)
logging.console.setLevel(logging.WARNING)
nIntervals=5
# Create space variables and a window
lineSpaceX = 0.55
lineSpaceY = 0.55
patch_orientation = 45 # zero is vertical, going anti-clockwise
surround_orientation = 90
#Jitter values
g_posJitter = 0.05 #gaussian positional jitter
r_posJitter = 0.05 #random positional jitter
g_oriJitter = 5 #gaussian orientation jitter
r_oriJitter = 5 #random orientation jitter
x_rand=random.randint(6,13) #random.randint(Return random integers from low (inclusive) to high (inclusive).
y_rand=random.randint(6,16)
#rectangular patch dimensions
width=15
height=12
message = visual.TextStim(win,pos=(0.0,-12.0),text='...Press SPACE to continue...')
fixation = visual.TextStim(win, pos=(0.0,0.0), text='X')
# Initialize clock to record response time
rt_clock = core.Clock()
class MyStim(object):
def __init__(self):
self.lines = []
for x in xrange(1, 33):
for y in xrange(1, 33):
x_pos = ((x - 32 / 2 - 1 / 2) * lineSpaceX +
random.gauss(0, g_posJitter))
y_pos = ((y - 32 / 2 - 1 / 2) * lineSpaceY +
random.gauss(0, g_posJitter))
if ((x_rand <= x < x_rand + width) and
(y_rand <= y < y_rand + height)):
Line_Orientation = random.gauss(patch_orientation,
g_oriJitter)
else:
Line_Orientation = random.gauss(surround_orientation,
g_oriJitter)
current_line = visual.Line(
win, units="deg", start=(0, 0), end=(0.0, 0.35),
pos=(x_pos, y_pos), ori=Line_Orientation,
autoLog=False
)
self.lines.append(current_line)
def draw(self):
[line.draw() for line in self.lines]
myStim = MyStim()
for frameN in range(10):
myStim.draw()
win.flip()
# Clear the screen
win.flip()
print x_rand, y_rand
core.quit()
Please do note that even with this approach, I am dropping frames on a 3-year-old laptop computer with relatively weak integrated graphics chip. But I suspect a modern, fast GPU would be able to handle this amount of visual objects just fine. In the worst case, you could pre-create a large set of stimuli, save them as a bitmap file via win.saveMovieFrames(), and present them as a pre-loaded SimpleImageStim during your actual study.

Mirror an image in JES

I'm trying to mirror an image. That is, if, e.g., a person is facing to the left, when the program terminates I want that person to now be facing instead to the right.
I understand how mirroring works in JES, but I'm unsure how to proceed here.
Below is what I'm trying; be aware that image is a global variable declared in another function.
def flipPic(image):
width = getWidth(image)
height = getHeight(image)
for y in range(0, height):
for x in range(0, width):
left = getPixel(image, x, y)
right = getPixel(image, width-x-1, y)
color = getColor(left)
setColor(right, color)
show(image)
return image
try this
width = getWidth(pic)
height = getHeight(pic)
for y in range (0,height):
for x in range (0, width/2):
left=getPixel(pic, x, y)
right=getPixel(pic, width-x-1,y)
color1=getColor(left)
color2=getColor(right)
setColor(right, color1)
setColor(left, color2)
repaint(pic)
I personally find that repaint is confusing for newbies (like me!).
I'd suggest something like this:
def mirrorImage(image):
width = getWidth(image)
height = getHeight(image)
for y in range (0,height):
for x in range (0, width/2):
left=getPixel(pic, x, y)
right=getPixel(pic, width-x-1,y)
color1=getColor(left)
color2=getColor(right)
setColor(right, color1)
setColor(left, color2)
show(image)
return image
mirrorImage(image)
This seems to work well.. I put some comments in so you can rewrite in your own style.
feel free to ask questions but I think your question may already be answered^^
#this function will take the pixel values for a selected picture and
#past them to a new canvas but fliped over!
def flipPic(pict):
#here we take the height and width of the original picture
width=getWidth(pict)
height=getHeight(pict)
#here we make and empty canvas
newPict=makeEmptyPicture(width,height)
#the Y for loop is setting the range to working for the y axes the started the X for loop
for y in range(0, height):
#the X for loop is setting the range to work in for the x axis
for x in range(0, width):
#here we are collecting the colour information for the origional pix in range of X and
colour=getColor(getPixel(pict,x,y))
#here we are setting the colour information to its new position on the blank canvas
setColor(getPixel(newPict,width-x-1,y),colour)
#setColor(getPixel(newPict,width-x-1,height-y-1),colour)#upsidedown
show(newPict)
#drive function
pict = makePicture(pickAFile())
show(pict)
flipPic(pict)
Might be easier to read if you copy it over to JES first :D
BTW I got full marks for this one in my intro to programming class ;)

Convert from latitude, longitude to x, y

I want to convert GPS location (latitude, longitude) into x,y coordinates.
I found many links about this topic and applied it, but it doesn't give me the correct answer!
I am following these steps to test the answer:
(1) firstly, i take two positions and calculate the distance between them using maps.
(2) then convert the two positions into x,y coordinates.
(3) then again calculate distance between the two points in the x,y coordinates
and see if it give me the same result in point(1) or not.
one of the solution i found the following, but it doesn't give me correct answer!
latitude = Math.PI * latitude / 180;
longitude = Math.PI * longitude / 180;
// adjust position by radians
latitude -= 1.570795765134; // subtract 90 degrees (in radians)
// and switch z and y
xPos = (app.radius) * Math.sin(latitude) * Math.cos(longitude);
zPos = (app.radius) * Math.sin(latitude) * Math.sin(longitude);
yPos = (app.radius) * Math.cos(latitude);
also i tried this link but still not work with me well!
any help how to convert from(latitude, longitude) to (x,y) ?
Thanks,
No exact solution exists
There is no isometric map from the sphere to the plane. When you convert lat/lon coordinates from the sphere to x/y coordinates in the plane, you cannot hope that all lengths will be preserved by this operation. You have to accept some kind of deformation. Many different map projections do exist, which can achieve different compromises between preservations of lengths, angles and areas. For smallish parts of earth's surface, transverse Mercator is quite common. You might have heard about UTM. But there are many more.
The formulas you quote compute x/y/z, i.e. a point in 3D space. But even there you'd not get correct distances automatically. The shortest distance between two points on the surface of the sphere would go through that sphere, whereas distances on the earth are mostly geodesic lengths following the surface. So they will be longer.
Approximation for small areas
If the part of the surface of the earth which you want to draw is relatively small, then you can use a very simple approximation. You can simply use the horizontal axis x to denote longitude λ, the vertical axis y to denote latitude φ. The ratio between these should not be 1:1, though. Instead you should use cos(φ0) as the aspect ratio, where φ0 denotes a latitude close to the center of your map. Furthermore, to convert from angles (measured in radians) to lengths, you multiply by the radius of the earth (which in this model is assumed to be a sphere).
x = r λ cos(φ0)
y = r φ
This is simple equirectangular projection. In most cases, you'll be able to compute cos(φ0) only once, which makes subsequent computations of large numbers of points really cheap.
I want to share with you how I managed the problem. I've used the equirectangular projection just like #MvG said, but this method gives you X and Y positions related to the globe (or the entire map), this means that you get global positions. In my case, I wanted to convert coordinates in a small area (about 500m square), so I related the projection point to another 2 points, getting the global positions and relating to local (on screen) positions, just like this:
First, I choose 2 points (top-left and bottom-right) around the area where I want to project, just like this picture:
Once I have the global reference area in lat and lng, I do the same for screen positions. The objects containing this data are shown below.
//top-left reference point
var p0 = {
scrX: 23.69, // Minimum X position on screen
scrY: -0.5, // Minimum Y position on screen
lat: -22.814895, // Latitude
lng: -47.072892 // Longitude
}
//bottom-right reference point
var p1 = {
scrX: 276, // Maximum X position on screen
scrY: 178.9, // Maximum Y position on screen
lat: -22.816419, // Latitude
lng: -47.070563 // Longitude
}
var radius = 6371; //Earth Radius in Km
//## Now I can calculate the global X and Y for each reference point ##\\
// This function converts lat and lng coordinates to GLOBAL X and Y positions
function latlngToGlobalXY(lat, lng){
//Calculates x based on cos of average of the latitudes
let x = radius*lng*Math.cos((p0.lat + p1.lat)/2);
//Calculates y based on latitude
let y = radius*lat;
return {x: x, y: y}
}
// Calculate global X and Y for top-left reference point
p0.pos = latlngToGlobalXY(p0.lat, p0.lng);
// Calculate global X and Y for bottom-right reference point
p1.pos = latlngToGlobalXY(p1.lat, p1.lng);
/*
* This gives me the X and Y in relation to map for the 2 reference points.
* Now we have the global AND screen areas and then we can relate both for the projection point.
*/
// This function converts lat and lng coordinates to SCREEN X and Y positions
function latlngToScreenXY(lat, lng){
//Calculate global X and Y for projection point
let pos = latlngToGlobalXY(lat, lng);
//Calculate the percentage of Global X position in relation to total global width
pos.perX = ((pos.x-p0.pos.x)/(p1.pos.x - p0.pos.x));
//Calculate the percentage of Global Y position in relation to total global height
pos.perY = ((pos.y-p0.pos.y)/(p1.pos.y - p0.pos.y));
//Returns the screen position based on reference points
return {
x: p0.scrX + (p1.scrX - p0.scrX)*pos.perX,
y: p0.scrY + (p1.scrY - p0.scrY)*pos.perY
}
}
//# The usage is like this #\\
var pos = latlngToScreenXY(-22.815319, -47.071718);
$point = $("#point-to-project");
$point.css("left", pos.x+"em");
$point.css("top", pos.y+"em");
As you can see, I made this in javascript, but the calculations can be translated to any language.
P.S. I'm applying the converted positions to an HTML element whose id is "point-to-project". To use this piece of code on your project, you shall create this element (styled as position absolute) or change the "usage" block.
Since this page shows up on top of google while i searched for this same problem, I would like to provide a more practical answers. The answer by MVG is correct but rather theoratical.
I have made a track plotting app for the fitbit ionic in javascript. The code below is how I tackled the problem.
//LOCATION PROVIDER
index.js
var gpsFix = false;
var circumferenceAtLat = 0;
function locationSuccess(pos){
if(!gpsFix){
gpsFix = true;
circumferenceAtLat = Math.cos(pos.coords.latitude*0.01745329251)*111305;
}
pos.x:Math.round(pos.coords.longitude*circumferenceAtLat),
pos.y:Math.round(pos.coords.latitude*110919),
plotTrack(pos);
}
plotting.js
plotTrack(position){
let x = Math.round((this.segments[i].start.x - this.bounds.minX)*this.scale);
let y = Math.round(this.bounds.maxY - this.segments[i].start.y)*this.scale; //heights needs to be inverted
//redraw?
let redraw = false;
//x or y bounds?
if(position.x>this.bounds.maxX){
this.bounds.maxX = (position.x-this.bounds.minX)*1.1+this.bounds.minX; //increase by 10%
redraw = true;
}
if(position.x<this.bounds.minX){
this.bounds.minX = this.bounds.maxX-(this.bounds.maxX-position.x)*1.1;
redraw = true;
};
if(position.y>this.bounds.maxY){
this.bounds.maxY = (position.y-this.bounds.minY)*1.1+this.bounds.minY; //increase by 10%
redraw = true;
}
if(position.y<this.bounds.minY){
this.bounds.minY = this.bounds.maxY-(this.bounds.maxY-position.y)*1.1;
redraw = true;
}
if(redraw){
reDraw();
}
}
function reDraw(){
let xScale = device.screen.width / (this.bounds.maxX-this.bounds.minX);
let yScale = device.screen.height / (this.bounds.maxY-this.bounds.minY);
if(xScale<yScale) this.scale = xScale;
else this.scale = yScale;
//Loop trough your object to redraw all of them
}
For completeness I like to add my python adaption of #allexrm code which worked really well. Thanks again!
radius = 6371 #Earth Radius in KM
class referencePoint:
def __init__(self, scrX, scrY, lat, lng):
self.scrX = scrX
self.scrY = scrY
self.lat = lat
self.lng = lng
# Calculate global X and Y for top-left reference point
p0 = referencePoint(0, 0, 52.526470, 13.403215)
# Calculate global X and Y for bottom-right reference point
p1 = referencePoint(2244, 2060, 52.525035, 13.405809)
# This function converts lat and lng coordinates to GLOBAL X and Y positions
def latlngToGlobalXY(lat, lng):
# Calculates x based on cos of average of the latitudes
x = radius*lng*math.cos((p0.lat + p1.lat)/2)
# Calculates y based on latitude
y = radius*lat
return {'x': x, 'y': y}
# This function converts lat and lng coordinates to SCREEN X and Y positions
def latlngToScreenXY(lat, lng):
# Calculate global X and Y for projection point
pos = latlngToGlobalXY(lat, lng)
# Calculate the percentage of Global X position in relation to total global width
perX = ((pos['x']-p0.pos['x'])/(p1.pos['x'] - p0.pos['x']))
# Calculate the percentage of Global Y position in relation to total global height
perY = ((pos['y']-p0.pos['y'])/(p1.pos['y'] - p0.pos['y']))
# Returns the screen position based on reference points
return {
'x': p0.scrX + (p1.scrX - p0.scrX)*perX,
'y': p0.scrY + (p1.scrY - p0.scrY)*perY
}
pos = latlngToScreenXY(52.525607, 13.404572);
pos['x] and pos['y] contain the translated x & y coordinates of the lat & lng (52.525607, 13.404572)
I hope this is helpful for anyone looking like me for the proper solution to the problem of translating lat lng into a local reference coordinate system.
Best
Its better to convert to utm coordinates, and treat that as x and y.
import utm
u = utm.from_latlon(12.917091, 77.573586)
The result will be (779260.623156606, 1429369.8665238516, 43, 'P')
The first two can be treated as x,y coordinates, the 43P is the UTM Zone, which can be ignored for small areas (width upto 668 km).

Getting image.default to use class-defined Axis functions?

Compare the following:
par(mfrow = 2)
image(x=as.POSIXct(1:100, origin = "1970-1-1"), z= matrix(rnorm(100*100), 100))
plot(x=as.POSIXct(1:100, origin = "1970-1-1"), (rnorm(100)))
It seems like image (and so, image.default) fails to take the class-defined Axis functions into account when plotting, while plot does. This is problematic, since I'm in the process of implementing some classes with custom pretty and format specifications that would have their own way of plotting an axis, so I want to having my own axis functions be called when image is used, than always use the numeric version.
I understand there's a way round this by plotting axis manually, calling image first with xaxt = "n", for instance. But this seems inconvenient and messy. Ideally, I'd like a solution that can just drop in to overlay the existing function while breaking as few things as possible. Any thoughts?
The simplest way is to suppress the axes on the call to image() with axes = FALSE then add them yourself. E.g.:
set.seed(42)
X <- as.POSIXct(1:100, origin = "1970-1-1")
Z <- matrix(rnorm(100*100), 100)
image(x = X, z = Z, axes = FALSE)
axis(side = 2)
axis.POSIXct(side = 1, x = X)
box()
This can also be done using the Axis() S3 generic:
image(x = X, z = Z, axes = FALSE)
axis(side = 2)
Axis(x = X, side = 1)
box()
So to actually try to Answer the Question, I would wrap this into a function that automates the various steps:
Image <- function(x = seq(0, 1, length.out = nrow(z)),
y = seq(0, 1, length.out = ncol(z)),
z, ...) {
image(x = X, z = Z, ..., axes = FALSE)
Axis(x = y, side = 2, ...)
Axis(x = X, side = 1, ...)
box()
}
Write your axis functions as S3 methods for the Axis() generic and class x and y appropriately do that your methods are called and the above should just work. All you need to remember is to change image() to Image().
You could also write your own image() method, and add your class to x to have it called instead of image.default() Depends on whether it makes sense for x to have a class or not?
The reason I would do this is that the only way to change image.default() R-wide is to edit the function and assign it to the graphics namespace or source your version and call it explicitly. This would need to be done each and every time you started R. A custom function could easily be sourced or added to your own local package of misc functions that you arrange to load as R is starting so that it is automagically available. See ?Startup for details of how you might arrange for this.