WEBVTT 00:00:00.000 --> 00:00:01.452 align:middle line:90% [SQUEAKING] 00:00:01.452 --> 00:00:03.872 align:middle line:90% [RUSTLING] 00:00:03.872 --> 00:00:05.808 align:middle line:90% [CLICKING] 00:00:05.808 --> 00:00:09.295 align:middle line:90% 00:00:09.295 --> 00:00:11.670 align:middle line:84% HELENA VALLICROSA: All right, so we are back to the code. 00:00:11.670 --> 00:00:14.280 align:middle line:84% And now we're going to start applying the concepts 00:00:14.280 --> 00:00:19.860 align:middle line:84% that we've been talking to on R. So the first thing 00:00:19.860 --> 00:00:22.200 align:middle line:90% is to read vectorial maps. 00:00:22.200 --> 00:00:23.790 align:middle line:90% How do we read vectorial maps? 00:00:23.790 --> 00:00:28.380 align:middle line:84% Well here I included a web page where you 00:00:28.380 --> 00:00:30.510 align:middle line:90% can download vectorial maps. 00:00:30.510 --> 00:00:37.080 align:middle line:84% They are basically physical vectors of the global Earth, 00:00:37.080 --> 00:00:41.520 align:middle line:84% so you can find the coastal barriers. 00:00:41.520 --> 00:00:44.910 align:middle line:84% The packages we're going to use are these three. 00:00:44.910 --> 00:00:47.410 align:middle line:90% I have already installed them. 00:00:47.410 --> 00:00:50.820 align:middle line:84% But feel free to install them, and then 00:00:50.820 --> 00:00:53.920 align:middle line:90% lock them into the session. 00:00:53.920 --> 00:00:57.630 align:middle line:84% There are several ways to read vectorial maps. 00:00:57.630 --> 00:01:01.600 align:middle line:84% I just include three of them here. 00:01:01.600 --> 00:01:02.700 align:middle line:90% There's this one. 00:01:02.700 --> 00:01:04.800 align:middle line:84% My personal preference is the second one. 00:01:04.800 --> 00:01:08.680 align:middle line:84% There's this third one that I just put them in common. 00:01:08.680 --> 00:01:15.540 align:middle line:84% So in the first one this, which is using this function right 00:01:15.540 --> 00:01:19.330 align:middle line:84% here, the projection needs to be specified previously. 00:01:19.330 --> 00:01:21.240 align:middle line:90% So here is what I am doing. 00:01:21.240 --> 00:01:25.560 align:middle line:84% I'm just saying that I'm using the projection longlat, which 00:01:25.560 --> 00:01:30.810 align:middle line:90% is longitude latitude, WGS84. 00:01:30.810 --> 00:01:33.600 align:middle line:84% So I have to put this between commas, 00:01:33.600 --> 00:01:37.240 align:middle line:84% and using this particular function here. 00:01:37.240 --> 00:01:38.860 align:middle line:84% So this is going to be the projection. 00:01:38.860 --> 00:01:42.000 align:middle line:84% And when I'm reading the map, what I have to do 00:01:42.000 --> 00:01:45.420 align:middle line:84% is to specify where this map is located in your computer, 00:01:45.420 --> 00:01:49.630 align:middle line:84% and then specify what projection do you want it to be. 00:01:49.630 --> 00:01:52.590 align:middle line:90% So you'll have that map here. 00:01:52.590 --> 00:01:54.780 align:middle line:84% It's giving me a warning, just information. 00:01:54.780 --> 00:01:56.790 align:middle line:90% But everything worked fine. 00:01:56.790 --> 00:02:00.630 align:middle line:84% And my personal preference is this one, where you don't even 00:02:00.630 --> 00:02:02.550 align:middle line:90% have to specify the projection. 00:02:02.550 --> 00:02:05.820 align:middle line:84% So it's going to be read by the package itself. 00:02:05.820 --> 00:02:10.850 align:middle line:84% You only have to specify the route from your computer. 00:02:10.850 --> 00:02:12.740 align:middle line:90% You use this. 00:02:12.740 --> 00:02:14.840 align:middle line:90% It gives you some information-- 00:02:14.840 --> 00:02:17.120 align:middle line:84% what it has read, what it includes. 00:02:17.120 --> 00:02:21.643 align:middle line:84% And then I'm just going to plot, just type plot, and the map 00:02:21.643 --> 00:02:23.060 align:middle line:84% you want to plot, and you're going 00:02:23.060 --> 00:02:26.720 align:middle line:90% to see how this map looks like. 00:02:26.720 --> 00:02:33.080 align:middle line:84% You see this is the boundaries of the ground. 00:02:33.080 --> 00:02:36.200 align:middle line:84% And then we move on to raster maps. 00:02:36.200 --> 00:02:37.760 align:middle line:90% This is pretty simple. 00:02:37.760 --> 00:02:43.690 align:middle line:84% The king or the best personal preference, 00:02:43.690 --> 00:02:47.970 align:middle line:84% but the best package to use raster is the package raster. 00:02:47.970 --> 00:02:51.720 align:middle line:84% So you can use it to manage everything 00:02:51.720 --> 00:02:53.040 align:middle line:90% you need from rasters. 00:02:53.040 --> 00:02:55.080 align:middle line:84% I'm just going to load it into the session. 00:02:55.080 --> 00:02:57.630 align:middle line:84% And it's as easy just to put raster 00:02:57.630 --> 00:03:00.120 align:middle line:90% here and the route of your map. 00:03:00.120 --> 00:03:03.510 align:middle line:84% I'm going to chart a temperature map that I've 00:03:03.510 --> 00:03:07.680 align:middle line:90% taken from WorldClairm. 00:03:07.680 --> 00:03:12.362 align:middle line:84% And it's in 10 minutes resolution. 00:03:12.362 --> 00:03:14.185 align:middle line:84% We're just going to see how it looks like. 00:03:14.185 --> 00:03:17.580 align:middle line:90% 00:03:17.580 --> 00:03:20.050 align:middle line:84% And this is how by default the map is created. 00:03:20.050 --> 00:03:22.200 align:middle line:84% Also, if you feel like magnifying your map, 00:03:22.200 --> 00:03:24.030 align:middle line:90% you can just click on zoom here. 00:03:24.030 --> 00:03:27.330 align:middle line:84% And this is going to pop out in an outside window. 00:03:27.330 --> 00:03:30.460 align:middle line:84% So you will be able to see it bigger. 00:03:30.460 --> 00:03:32.430 align:middle line:84% And then there is a particular way 00:03:32.430 --> 00:03:36.700 align:middle line:84% of displaying maps which is using 00:03:36.700 --> 00:03:41.070 align:middle line:84% NC format, which is when you are working on time series maps. 00:03:41.070 --> 00:03:45.810 align:middle line:84% Just because the maps are pretty heavy data, 00:03:45.810 --> 00:03:49.230 align:middle line:84% this is a particular way to store time series 00:03:49.230 --> 00:03:51.120 align:middle line:90% in a pretty efficient way. 00:03:51.120 --> 00:03:53.830 align:middle line:84% But that makes it a little tricky to work with. 00:03:53.830 --> 00:03:56.650 align:middle line:84% So I'm just going to show you how to do that. 00:03:56.650 --> 00:03:59.670 align:middle line:84% I'm going to clean my environment 00:03:59.670 --> 00:04:01.660 align:middle line:90% to not being distracting. 00:04:01.660 --> 00:04:05.198 align:middle line:90% 00:04:05.198 --> 00:04:06.990 align:middle line:84% These are the packages you're going to need 00:04:06.990 --> 00:04:09.480 align:middle line:90% to go through this code. 00:04:09.480 --> 00:04:11.940 align:middle line:90% It's going to load them all. 00:04:11.940 --> 00:04:14.490 align:middle line:84% And this is a map that I have obtained 00:04:14.490 --> 00:04:17.160 align:middle line:90% based on this reference here. 00:04:17.160 --> 00:04:20.130 align:middle line:84% If you click on that link, you would 00:04:20.130 --> 00:04:23.400 align:middle line:84% be able to download this information from the internet. 00:04:23.400 --> 00:04:26.190 align:middle line:84% It's a nitrogen deposition map that goes from, 00:04:26.190 --> 00:04:31.170 align:middle line:84% if I remember correctly, from 1901 to 2020 00:04:31.170 --> 00:04:32.350 align:middle line:90% or something like that. 00:04:32.350 --> 00:04:34.740 align:middle line:84% So every time to time there is a map. 00:04:34.740 --> 00:04:36.190 align:middle line:84% So that's why it's a time series. 00:04:36.190 --> 00:04:39.150 align:middle line:84% So you have to picture, let's say a book. 00:04:39.150 --> 00:04:41.430 align:middle line:84% And each page of the book is a map. 00:04:41.430 --> 00:04:43.080 align:middle line:90% So you have them all together. 00:04:43.080 --> 00:04:46.230 align:middle line:84% And they are all the same size, the same resolution. 00:04:46.230 --> 00:04:52.110 align:middle line:84% But you have a repetition in time of the same map. 00:04:52.110 --> 00:04:54.160 align:middle line:84% OK, first of all, is to open the file. 00:04:54.160 --> 00:04:57.450 align:middle line:90% So nc_open where the map is. 00:04:57.450 --> 00:04:58.890 align:middle line:90% You take the map. 00:04:58.890 --> 00:05:02.730 align:middle line:84% And if that would be a raster, you 00:05:02.730 --> 00:05:04.540 align:middle line:84% would be able to plot it right away. 00:05:04.540 --> 00:05:06.110 align:middle line:90% So that's what I try here. 00:05:06.110 --> 00:05:06.610 align:middle line:90% No worries. 00:05:06.610 --> 00:05:09.130 align:middle line:84% It's not going to work, but it's just to show you 00:05:09.130 --> 00:05:11.650 align:middle line:84% that it's a different way of organizing maps. 00:05:11.650 --> 00:05:14.170 align:middle line:84% So how do we do it, to extract it 00:05:14.170 --> 00:05:17.110 align:middle line:84% and to convert it into a map we can see, we can visualize, 00:05:17.110 --> 00:05:19.030 align:middle line:90% we can understand? 00:05:19.030 --> 00:05:21.490 align:middle line:84% The first thing we need to do is to see 00:05:21.490 --> 00:05:24.610 align:middle line:84% what are the names of the dimension of the map. 00:05:24.610 --> 00:05:28.820 align:middle line:84% Just click names, the map, and dimensions. 00:05:28.820 --> 00:05:31.300 align:middle line:84% And this is going to return the three dimensions 00:05:31.300 --> 00:05:33.910 align:middle line:84% that we need to know which is the longitude, the latitude, 00:05:33.910 --> 00:05:34.730 align:middle line:90% and the time. 00:05:34.730 --> 00:05:37.060 align:middle line:84% But sometimes, the author's name, this variable 00:05:37.060 --> 00:05:38.030 align:middle line:90% is differently. 00:05:38.030 --> 00:05:41.080 align:middle line:84% So here is longlat, but it could be longitude latitude, 00:05:41.080 --> 00:05:43.640 align:middle line:84% or time could be years, or things like that. 00:05:43.640 --> 00:05:46.510 align:middle line:84% So that's why we need to make sure how this is named. 00:05:46.510 --> 00:05:48.940 align:middle line:84% So we're going to extract the longitude. 00:05:48.940 --> 00:05:51.040 align:middle line:84% Here is where we get the map structure. 00:05:51.040 --> 00:05:52.600 align:middle line:90% We have longitude. 00:05:52.600 --> 00:05:55.480 align:middle line:90% We variable get the longitude. 00:05:55.480 --> 00:05:58.480 align:middle line:90% OK, and we store it in a vector. 00:05:58.480 --> 00:06:00.370 align:middle line:84% And here we want to extract the latitude. 00:06:00.370 --> 00:06:03.880 align:middle line:84% We repeat the same, but with latitude instead. 00:06:03.880 --> 00:06:10.590 align:middle line:84% And here we are extracting the information related to the time. 00:06:10.590 --> 00:06:20.490 align:middle line:84% And now we see that the latitude is cut in 360 different columns 00:06:20.490 --> 00:06:25.830 align:middle line:84% or rows, and the longitude likewise, but 720. 00:06:25.830 --> 00:06:29.920 align:middle line:84% And then we want to get the actual information. 00:06:29.920 --> 00:06:31.810 align:middle line:84% So what's the content of the cells? 00:06:31.810 --> 00:06:36.730 align:middle line:90% So we do this like that. 00:06:36.730 --> 00:06:38.430 align:middle line:90% So here is the content. 00:06:38.430 --> 00:06:42.280 align:middle line:84% Something else we need to take into account is the NA values. 00:06:42.280 --> 00:06:46.770 align:middle line:84% So when creating a map, there is a value 00:06:46.770 --> 00:06:50.400 align:middle line:90% that you use to name your NA. 00:06:50.400 --> 00:06:52.380 align:middle line:90% Sometimes it's NA right away. 00:06:52.380 --> 00:06:56.100 align:middle line:84% But some other people use numbers like 9,999, or just 00:06:56.100 --> 00:06:57.270 align:middle line:90% a big number. 00:06:57.270 --> 00:07:01.530 align:middle line:84% And here what we are doing is to explore how the authors have 00:07:01.530 --> 00:07:04.510 align:middle line:90% named this NA value. 00:07:04.510 --> 00:07:10.240 align:middle line:90% So this one I want to see. 00:07:10.240 --> 00:07:11.020 align:middle line:90% I'm curious. 00:07:11.020 --> 00:07:14.090 align:middle line:84% This is the big number they named as missing value. 00:07:14.090 --> 00:07:17.620 align:middle line:84% So to avoid this number to mess with our results, 00:07:17.620 --> 00:07:19.990 align:middle line:84% I recommend you to change it to NA. 00:07:19.990 --> 00:07:21.650 align:middle line:90% So that's what I'm doing here. 00:07:21.650 --> 00:07:26.433 align:middle line:84% I'm replacing every number that looks like this, to an NA. 00:07:26.433 --> 00:07:27.850 align:middle line:84% Don't worry that you are not going 00:07:27.850 --> 00:07:29.800 align:middle line:90% to knock out important data. 00:07:29.800 --> 00:07:32.970 align:middle line:84% It's just mostly going to be NAs. 00:07:32.970 --> 00:07:36.330 align:middle line:90% We run this chunk of code. 00:07:36.330 --> 00:07:36.960 align:middle line:90% Oh, yeah. 00:07:36.960 --> 00:07:37.950 align:middle line:90% Sorry about that. 00:07:37.950 --> 00:07:40.750 align:middle line:90% 00:07:40.750 --> 00:07:41.590 align:middle line:90% Now, it should go. 00:07:41.590 --> 00:07:44.442 align:middle line:90% 00:07:44.442 --> 00:07:46.525 align:middle line:84% It's taking a while because there's a lot of data. 00:07:46.525 --> 00:07:53.430 align:middle line:90% 00:07:53.430 --> 00:07:55.120 align:middle line:90% Oh yeah, here we have it. 00:07:55.120 --> 00:07:59.970 align:middle line:84% So now all the NAs would be replaced into NA value. 00:07:59.970 --> 00:08:02.550 align:middle line:84% And now we no longer need to have opened them up. 00:08:02.550 --> 00:08:06.051 align:middle line:84% So we can close it and it doesn't occupy space 00:08:06.051 --> 00:08:07.360 align:middle line:90% in our session. 00:08:07.360 --> 00:08:10.110 align:middle line:84% Just close it because we already have the information we need. 00:08:10.110 --> 00:08:12.630 align:middle line:90% 00:08:12.630 --> 00:08:17.610 align:middle line:84% And how are we going to transform this information we 00:08:17.610 --> 00:08:19.950 align:middle line:84% have in different chunks into an organized map 00:08:19.950 --> 00:08:23.160 align:middle line:84% that we can actually visualize and work with? 00:08:23.160 --> 00:08:26.620 align:middle line:84% First of all, here I'm going to run an example. 00:08:26.620 --> 00:08:32.789 align:middle line:84% I'm just going to use the package raster right here. 00:08:32.789 --> 00:08:36.179 align:middle line:84% I need to include this t here, which means transpose, 00:08:36.179 --> 00:08:38.520 align:middle line:84% because otherwise if I don't put transpose, 00:08:38.520 --> 00:08:41.309 align:middle line:90% the image would look flipped. 00:08:41.309 --> 00:08:43.240 align:middle line:90% Then this is the object. 00:08:43.240 --> 00:08:45.300 align:middle line:84% These are the different dimensions-- longitude, 00:08:45.300 --> 00:08:47.550 align:middle line:84% latitude, and this number 1 is going 00:08:47.550 --> 00:08:49.450 align:middle line:90% to be the first time frame. 00:08:49.450 --> 00:08:54.880 align:middle line:84% So I'm going to just get the first map that we have. 00:08:54.880 --> 00:09:00.290 align:middle line:84% Then it asks us for the minimum of the x-axis. 00:09:00.290 --> 00:09:02.350 align:middle line:84% I'm going to put the minimum of the longitude, 00:09:02.350 --> 00:09:07.750 align:middle line:84% the maximum of the longitude, and just basically setting up 00:09:07.750 --> 00:09:11.770 align:middle line:90% the format of this raster map. 00:09:11.770 --> 00:09:15.260 align:middle line:84% You have to specify as well the projection. 00:09:15.260 --> 00:09:17.080 align:middle line:84% So this is going to be the projection 00:09:17.080 --> 00:09:21.700 align:middle line:84% that it's the same that we've used before in other maps. 00:09:21.700 --> 00:09:23.965 align:middle line:84% And we just run this chunk of code. 00:09:23.965 --> 00:09:26.550 align:middle line:90% 00:09:26.550 --> 00:09:30.520 align:middle line:90% And we can plot our results. 00:09:30.520 --> 00:09:32.460 align:middle line:90% This is how the map looks like. 00:09:32.460 --> 00:09:37.530 align:middle line:84% This is the nitrogen deposition in, I believe in 1901. 00:09:37.530 --> 00:09:39.630 align:middle line:90% And it includes also the sea. 00:09:39.630 --> 00:09:43.710 align:middle line:84% So that's why it doesn't look like the Earth 00:09:43.710 --> 00:09:45.430 align:middle line:90% that we're used to. 00:09:45.430 --> 00:09:49.590 align:middle line:84% And then how can we store this information in our computer? 00:09:49.590 --> 00:09:52.800 align:middle line:90% How can we write this raster? 00:09:52.800 --> 00:09:56.730 align:middle line:84% So it's just as easy as write raster, put 00:09:56.730 --> 00:10:00.090 align:middle line:84% the name of the file we want to store, file name, 00:10:00.090 --> 00:10:02.220 align:middle line:90% and your route as follows. 00:10:02.220 --> 00:10:07.190 align:middle line:90% 00:10:07.190 --> 00:10:09.430 align:middle line:84% So now we are moving to the resolution. 00:10:09.430 --> 00:10:12.180 align:middle line:84% And you might have paid attention 00:10:12.180 --> 00:10:14.880 align:middle line:84% when downloading the data from the WorldClaim 00:10:14.880 --> 00:10:17.070 align:middle line:84% that it allows you to download the maps 00:10:17.070 --> 00:10:18.420 align:middle line:90% in different resolutions. 00:10:18.420 --> 00:10:21.780 align:middle line:84% But in order to name the different resolutions, 00:10:21.780 --> 00:10:24.670 align:middle line:90% WorldClaim, it uses time. 00:10:24.670 --> 00:10:25.810 align:middle line:90% So why is that? 00:10:25.810 --> 00:10:28.380 align:middle line:84% Well actually, you could face three different ways 00:10:28.380 --> 00:10:30.370 align:middle line:90% to approach resolution. 00:10:30.370 --> 00:10:35.040 align:middle line:84% The first of all is the surface using the surface square. 00:10:35.040 --> 00:10:38.010 align:middle line:84% One example would is 1 kilometer square. 00:10:38.010 --> 00:10:42.630 align:middle line:84% That refers to the map when we have it in a representation. 00:10:42.630 --> 00:10:44.670 align:middle line:84% In a gridded representation, we would 00:10:44.670 --> 00:10:50.220 align:middle line:84% have each side of the grid calculated by the surface 00:10:50.220 --> 00:10:51.120 align:middle line:90% that it's occupying. 00:10:51.120 --> 00:10:56.290 align:middle line:84% So just take this that's 1 kilometer. 00:10:56.290 --> 00:10:57.820 align:middle line:90% And that's 1 kilometer. 00:10:57.820 --> 00:11:01.450 align:middle line:84% The problem of this approach is that it's not always accurate. 00:11:01.450 --> 00:11:06.970 align:middle line:84% Because the part of the grid that's closer to 00:11:06.970 --> 00:11:12.130 align:middle line:84% the equator is smaller than the one that it goes to the pole. 00:11:12.130 --> 00:11:16.070 align:middle line:84% So it stretches when it goes to the edges. 00:11:16.070 --> 00:11:18.400 align:middle line:84% And so that makes that this 1 kilometer is not 00:11:18.400 --> 00:11:20.230 align:middle line:84% consistent throughout the whole map. 00:11:20.230 --> 00:11:22.990 align:middle line:84% And to overcome this problem, it came 00:11:22.990 --> 00:11:26.110 align:middle line:84% with the angle or the time approach, which treats 00:11:26.110 --> 00:11:28.420 align:middle line:90% the Earth as a round surface. 00:11:28.420 --> 00:11:33.260 align:middle line:84% This is not perfect because, the round is not 100% perfect, 00:11:33.260 --> 00:11:35.720 align:middle line:84% but it's better than using the surface. 00:11:35.720 --> 00:11:39.340 align:middle line:84% So what they do is to consider on one side 00:11:39.340 --> 00:11:42.730 align:middle line:90% the angle that this opening is. 00:11:42.730 --> 00:11:46.420 align:middle line:84% So just let's take this square right here. 00:11:46.420 --> 00:11:49.180 align:middle line:84% And let's just plot it on top of this. 00:11:49.180 --> 00:11:54.680 align:middle line:84% So that the angle that covers this part 00:11:54.680 --> 00:11:57.530 align:middle line:84% of the surface, that would be displayed in the angle, 00:11:57.530 --> 00:12:03.320 align:middle line:84% or also the time that the Earth needs to rotate and cover 00:12:03.320 --> 00:12:04.800 align:middle line:90% this amount of surface. 00:12:04.800 --> 00:12:06.650 align:middle line:84% So for you to have a reference, for example, 00:12:06.650 --> 00:12:13.040 align:middle line:84% 1 kilometer square resolution would be the same as 30 seconds 00:12:13.040 --> 00:12:13.760 align:middle line:90% in time. 00:12:13.760 --> 00:12:22.270 align:middle line:90% 00:12:22.270 --> 00:12:23.790 align:middle line:90% So going back to the code. 00:12:23.790 --> 00:12:27.390 align:middle line:84% Here I downloaded two different resolutions 00:12:27.390 --> 00:12:30.880 align:middle line:84% for the temperature maps on WorldClaim. 00:12:30.880 --> 00:12:32.880 align:middle line:90% One is 10 minutes. 00:12:32.880 --> 00:12:35.280 align:middle line:90% And the other one is 30 seconds. 00:12:35.280 --> 00:12:37.230 align:middle line:84% The 10 minutes is OK to download. 00:12:37.230 --> 00:12:40.860 align:middle line:84% The 30 seconds, it might take a while. 00:12:40.860 --> 00:12:44.820 align:middle line:84% If your internet connection is slow, 00:12:44.820 --> 00:12:47.650 align:middle line:84% you can just believe what I'm saying. 00:12:47.650 --> 00:12:52.080 align:middle line:84% But if you want to try it out, obviously feel free. 00:12:52.080 --> 00:12:54.120 align:middle line:84% Just to remind you how the map looks like, 00:12:54.120 --> 00:12:56.350 align:middle line:90% it's going to look like this. 00:12:56.350 --> 00:13:01.500 align:middle line:84% Let's just check the resolution here on both maps. 00:13:01.500 --> 00:13:03.460 align:middle line:90% Here we have this number here. 00:13:03.460 --> 00:13:04.470 align:middle line:90% But what does it mean? 00:13:04.470 --> 00:13:06.880 align:middle line:84% Here we have this other number here. 00:13:06.880 --> 00:13:09.390 align:middle line:84% So when we consult the resolution in our maps, 00:13:09.390 --> 00:13:13.200 align:middle line:84% it's going to be shown in degrees, so using the angle 00:13:13.200 --> 00:13:17.110 align:middle line:84% approach that I previously mentioned. 00:13:17.110 --> 00:13:20.970 align:middle line:84% So how can we change resolution in a map? 00:13:20.970 --> 00:13:23.960 align:middle line:90% We can use the factor aggregate. 00:13:23.960 --> 00:13:28.330 align:middle line:84% So if we have a number that's bigger than 1, 00:13:28.330 --> 00:13:30.170 align:middle line:90% we are going to combine cells. 00:13:30.170 --> 00:13:34.630 align:middle line:84% So if we have in this case, I'm combining in a factor of 4, 00:13:34.630 --> 00:13:38.140 align:middle line:84% meaning that four cells horizontal and four cells 00:13:38.140 --> 00:13:41.410 align:middle line:84% vertical are going to be combined in one. 00:13:41.410 --> 00:13:46.220 align:middle line:84% There are different ways to calculate the resultant cell. 00:13:46.220 --> 00:13:49.630 align:middle line:84% So it could be using the mode, or it could be using the mean, 00:13:49.630 --> 00:13:52.810 align:middle line:84% depending on what kind of data you have in your map. 00:13:52.810 --> 00:13:57.910 align:middle line:84% But you could also increase your resolution 00:13:57.910 --> 00:14:00.880 align:middle line:84% by using a number that's lower than 1. 00:14:00.880 --> 00:14:03.520 align:middle line:84% So let's if you put, let's say 0.5, 00:14:03.520 --> 00:14:06.760 align:middle line:84% you are going to divide a cell in 4. 00:14:06.760 --> 00:14:12.670 align:middle line:84% Because we're working in two dimensions. 00:14:12.670 --> 00:14:15.080 align:middle line:84% I mean this is technically correct, 00:14:15.080 --> 00:14:17.560 align:middle line:84% but conceptually it doesn't really make a lot of sense. 00:14:17.560 --> 00:14:19.913 align:middle line:84% Because you are creating fake data. 00:14:19.913 --> 00:14:21.580 align:middle line:84% It's not that you are actually including 00:14:21.580 --> 00:14:24.460 align:middle line:84% the resolution of how good you are approaching reality. 00:14:24.460 --> 00:14:31.190 align:middle line:84% You are just creating more data for no more accuracy. 00:14:31.190 --> 00:14:34.720 align:middle line:84% So in this case, I'm going to aggregate the map 00:14:34.720 --> 00:14:38.050 align:middle line:90% that we have in a factor of 4. 00:14:38.050 --> 00:14:42.490 align:middle line:84% And I'm just going to consult how the resolution has changed. 00:14:42.490 --> 00:14:45.670 align:middle line:84% So initially I aggregated this one. 00:14:45.670 --> 00:14:47.260 align:middle line:90% This was the initial resolution. 00:14:47.260 --> 00:14:51.100 align:middle line:84% And once the resolution was changed, 00:14:51.100 --> 00:14:53.020 align:middle line:84% I see the degrees has gone bigger 00:14:53.020 --> 00:14:54.950 align:middle line:90% because the surface is bigger. 00:14:54.950 --> 00:15:01.730 align:middle line:84% So the time or the degree to cover that surface is bigger. 00:15:01.730 --> 00:15:04.390 align:middle line:84% So if you plot that, you might be 00:15:04.390 --> 00:15:10.920 align:middle line:84% able to see that the quality of the image is a little worse. 00:15:10.920 --> 00:15:15.000 align:middle line:90%