Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated: 1 00:00:01,310 --> 00:00:07,680 Hey! Hi again and welcome to this new lecture! What we have so far is this map 3 00:00:07,680 --> 00:00:13,590 with this 62 markers each of them representing a volcano location in the 5 00:00:13,590 --> 00:00:20,579 United States, however this map is not very smart so to say. The only 7 00:00:20,579 --> 00:00:28,949 information that this map conveys is the locations of the volcanoes and you also 9 00:00:28,949 --> 00:00:33,829 have a base map. There's also a good aspect of this now because you can 11 00:00:33,829 --> 00:00:39,179 extract information like that if you click the icons, however you may want to 13 00:00:39,179 --> 00:00:44,850 transform this map to actually show an attribute instead of just volcano 15 00:00:44,850 --> 00:00:50,789 locations and the way to do that, there may be different way and that's up to your 17 00:00:50,789 --> 00:00:57,030 knowledge about cartography, but I could make the map show an attribute here. 19 00:00:57,030 --> 00:01:02,249 For example I could change the colors of these markers to actually show the 21 00:01:02,249 --> 00:01:09,210 elevation range. Let's say we can categorize these markers into three 23 00:01:09,210 --> 00:01:16,920 colors, let's say green, orange, and red. Green would be four elevations from zero 25 00:01:16,920 --> 00:01:23,909 to a 1 000 meter for example or 2 000 meters, and orange would be from 2 000 to 27 00:01:23,909 --> 00:01:30,119 3 000 meters, and then red markers would represent volcanoes with an 29 00:01:30,119 --> 00:01:37,350 elevation of higher than 3 000 meters. So how do we do that with Folium? Let's get 31 00:01:37,350 --> 00:01:43,680 back to Atom. Here is our code. What we have so far? Currently what we're passing 33 00:01:43,680 --> 00:01:51,689 to icon argument is a color argument with a value of green, so basically what 35 00:01:51,689 --> 00:01:55,369 we need to do we need to make this dynamic so that the color changes 37 00:01:55,369 --> 00:02:01,079 depending on the elevation. Unfortunately we cannot do that with 39 00:02:01,079 --> 00:02:06,179 Folium, so folium doesn't have native functionality to create dynamic colors 41 00:02:06,179 --> 00:02:13,320 for your markers, therefore we need to be a bit creative here and use Python core 43 00:02:13,320 --> 00:02:17,580 functionalities to do this, and when you think 45 00:02:17,580 --> 00:02:22,890 about dynamics, I think about functions so basically this loop is 47 00:02:22,890 --> 00:02:28,799 going through latitude, longitude, elevation and then it passes those three 49 00:02:28,799 --> 00:02:36,019 values into this expression in here. However color is being passed as a 51 00:02:36,019 --> 00:02:41,730 a string always, but how do I change it depending on the elevation for instance? 53 00:02:41,730 --> 00:02:46,459 Well the way to do that is by creating a function, a function that gets as input 55 00:02:46,459 --> 00:02:53,430 elevation and then it does some actions inside the function, and then it returns 57 00:02:53,430 --> 00:02:59,099 a color depending on the elevation value. So you can say if elevation is less than 59 00:02:59,099 --> 00:03:07,829 this give me green color, a green string here, and so on and so forth. So to give 61 00:03:07,829 --> 00:03:12,540 you an idea the way this would work is, let me write a function here, this 63 00:03:12,540 --> 00:03:17,609 would be a good place to do that before creating the map object, but always 65 00:03:17,609 --> 00:03:21,720 always you need to create the function because I will be calling the function 67 00:03:21,720 --> 00:03:27,599 in here so you need to create the function before this expression, so from 69 00:03:27,599 --> 00:03:36,290 here and upwards. I'll be creating that in here. Let's call a function color 71 00:03:36,290 --> 00:03:43,620 producer. Let's keep it simple for a while just to demonstrate you how this 73 00:03:43,620 --> 00:03:50,730 would work, so let's keep it very very simple. Let's say return green, and if you 75 00:03:50,730 --> 00:03:59,459 change this to color producer and don't forget the brackets, by passing brackets 77 00:03:59,459 --> 00:04:04,349 that means you are calling the function. If you don't pass in the bracket so that 79 00:04:04,349 --> 00:04:08,280 means you're just calling the function name and you are not executing the 81 00:04:08,280 --> 00:04:17,489 function, so I'll just keep it like that. And go ahead and execute 83 00:04:17,489 --> 00:04:19,820 map1.py . All right, reload and you'll get the same 85 00:04:25,300 --> 00:04:33,460 thing, right, because what happens is that this thing in here this function call 87 00:04:33,460 --> 00:04:41,650 will be equal to whatever you return here, so the type of this object it's 89 00:04:41,650 --> 00:04:47,440 actually a string so it's exactly the green string. Therefore now you can add 91 00:04:47,440 --> 00:04:53,169 some conditionals here. Basically you need to pass an input here, so elevation 93 00:04:53,169 --> 00:05:01,180 let me write whatever variable you like. I'll write elevation and here you need to pass 95 00:05:01,180 --> 00:05:10,240 el, so el for lat, lon, el. Let's say we have 62 rows in the data table, 97 00:05:10,240 --> 00:05:15,940 and for loop will go through the first row of the table, it will get elevation and 99 00:05:15,940 --> 00:05:22,150 it will pass it to this function code, so the function will pass el into elevation, 101 00:05:22,150 --> 00:05:34,110 and then you say here if elevation is less than 1 000, then you want to 103 00:05:34,110 --> 00:05:44,860 return green for elevations less than 1000 meters, elif elevation is 105 00:05:44,860 --> 00:05:55,110 between 1 000 meters, so it's greater than 1 000 meters, or less 107 00:05:55,110 --> 00:06:04,500 then let's say 3 000 meters, return orange, else return red, so red will be returned 109 00:06:11,710 --> 00:06:17,020 if none of these conditional is satisfied which means elevation is 111 00:06:17,020 --> 00:06:25,090 neither less than 1 000 meters, nor between 1 000 and 3 000 meters 113 00:06:25,090 --> 00:06:30,610 which means what is left is greater than 3 000 meters. 115 00:06:30,610 --> 00:06:34,920 In that case we return red. For finding out what values actually, 117 00:06:34,920 --> 00:06:40,530 you need to do a little bit of data exploration, for instance you need to, 119 00:06:40,530 --> 00:06:47,390 you may want to look at the data quickly like that to see what values you have. 121 00:06:47,390 --> 00:06:56,690 And then decide all the category thresholds, but you can also make more 123 00:06:56,690 --> 00:07:01,950 significant statistical analysis like you can make a histogram and see the 125 00:07:01,950 --> 00:07:06,810 data distribution and then decide on these values, but let's keep things 127 00:07:06,810 --> 00:07:15,270 simple and let's decide on these values. Okay, I'll save this, check if everything 129 00:07:15,270 --> 00:07:29,820 is in place just quickly, yeah, let me try the code. Go and reload and yeah, we have 131 00:07:29,820 --> 00:07:38,250 some different colors here, yeah this is looking good. Let me double check the 133 00:07:38,250 --> 00:07:43,110 values. For instance oranges between 1 000 meters and 3 000 meters 135 00:07:43,110 --> 00:07:50,570 Yeah, we're doing good. Red is above 3 000 meters. 137 00:07:50,570 --> 00:07:55,000 Yeah, it seems it's working. 8166