Creating Spatial Distribution Maps in QGIS Part 2

[Music] [Music] [Music] hi guys welcome to this tutorial this is part 2 of the lesson generating maps showing special distribution in qgis you can follow part 1 from the links in the description below in lesson 1 we covered interpolation of heavy metal concentration data for our area of interest and had the results for it so let's go to kgs and continue with the exercise electropen qgis and in our previous lesson we had gone through the interpolation of the different heavy metals that is mercury arsenic nickel zinc cadmium chromium copper and lead and we had even gone ahead and styled one of the layers which was mercury so i'm going to just turn on the mercury layer and this is our result for the mercury layer so what you want to do today is we want to actually create the distribution maps for each and every element here so we're going to start with the mercury and this is the razer layer for mercury including the styling of the layer the first thing we want to do is we want to do away with the excesses the ones the regions that are outside our area of interest remember this is our area of interest let me just uh try and change the symbology of our area of interest but it's a bit visible to everyone so i'm going to just change the color a brighter color then i'm going to also change the thickness i want it to be a bit big so it's visible then apply okay so this is origin of interest and our point data for the heavy metals i'm just going to also change the symbology and put a different symbol like say that nice uh right damn red diamond so actually this is a the point data that we had and this is our original interest so what you want to do is now we have already done an inter adw interpolation for for mercury and all the other elements so we want to start with mercury the first thing we need to do is we need to clip the raster layer using our region of interest to do the clipping is very very simple process we're going to go to raster then we're going to select extraction then we're going to select extract by mask layer because you want to use our project area which is in nairobi as a mask layer and then you're going to now put in parameters for this so for the input layer we're going to start with mercury this is our raster layer so i'm going to select mercury and drop it in my input layer then the mask layer is the project area which is nairobi i'm going to insert that then i'm going to leave the source crs and the target series as a blank and then also i'm not going to assign any values here and i'm just going to scroll down to then i'm going to just leave everything by this default then i'm going to create a permanent layer of this so i'm going to click on this drop down here click on save to file so i'm going to create a new folder within the raster file i'm going to call them clipped so i might say clips and within the clip layer i'm going to start with mercury so i'm going to start with mercury these are the clipped files so i'm going to click on save then i'm going to click on run to run the process and the clip is finished so let's look at let's look at our results i'm going to click on close and now you can see now we have a new layer here for mercury there's the initial one which was mercury concentration and we have now the clip for mercury here so what i'm going to do is i'm going to just copy the style because you can see now this is a single van gray scale and this one was already symbolized so i'm just going to copy the same same style that was in our initial layer which was for the whole of this region here and applied to the clipped layer so what i'm going to do is i'm going to copy this style right click go to style and i'm going to copy the style and i'm going to make sure that i use the same same style in my now my mercury layer so i'm going to go to style again then i'm going to paste this time and you can see now there's a little bit of difference so i'm going to remove now my initial layer i can even uncheck it or just remove it completely from my qgis i'm going to remove it so now we have the one for mercury now we need to do the same thing for all the other metals so i'm going to go to now arsenic you can see it's still gray scale because we had not done any symbology so what the first thing we're going to do is we're going to clip it first then we're going to apply the same same style that we have actually used in mercury so i'm going to go to rust again then extraction extract my mask i'm going to do the same thing and this time i'm going to select ascenic instead of mercury and then i'm going to use the same same layer that is the project area as my mask layer and then i'm going to leave everything else the same and i'm going to scroll down and i'm going to save a permanent layer here save the file and i'm going to save it now in my clip file and i'm going to say ascenic and it's a tip file so i'm going to click on save and i'm going to click on run the task is complete i'm going to click on close and then i'm going to see if actually it was clipped and you can see it was clips i'm going to remove the initial layer which is acidic and i'm going to do the same thing for all the other layers before we can do the styling so i'm going to fast forward this video so that you can go to the next step the process is complete so and i'm going to remove also the last layer that i have actually clipped which is lead and remember you can always run all these as a bad process by just going to raster extraction clip by mask if you want to save on time then instead of clipping one by one you can just click on run as a batch process and you insert all these uh layers here within these uh dialog box and you can autofill everything and just run it as one process but uh i've completed so let's go to the next step so we have the mercury which we have already done symbolization of so we're going to do the first map which is of mercury then you're going to do subsequent maps of ascenic michael zinc cadmium chromium copper and lid to create the distribution maps the next thing i'm going to do is we're going to go to project and then we're going to go to the new print layout because you have to go to access the print composer then we're going to give the new print layout a title and i'm going to call it distribution maps then i'm going to say okay and the print composer interface appears so i'm going to maximize it then the next thing we're going to do is we're going to first determine the kind of page size we want to do our map on so i'm going to right click on the blank layer then go to paint properties and you can see the current size which is preset is an a4 and it's landscape but i want to have an a3 and it's actually now a bigger paper zero to 420 by width and a height of 297 so i'm going to do a customization i don't i neither want a landscape nor a portrait i want a page that has equal width and recall height so i can see i have a width of 420 so i'm going to do the same thing for the height i'm going to change it to 420 and now we have a page that is equal in width and length so that is the first thing i'm going to do so i've actually created a custom page for my maps so the next thing i'm going to do is i'm going to now add my elements and the first thing i'm going to be adding is my map so i'm going to select on add item then add map then i'm going to select where i want my first map that is for mercury to be i'm just going to select it up to maybe there then i'm going to scale the map to maybe instead of 6 4 000 maybe 55 000 so it can fit well in my work area then i'm going to just go back to qj so that i can turn off the the base map so that you can just remain with the the mercury layer only so i'm going to go back to okay then i'm going to turn off the google satellite hybrid then i'm going to go back to my print composer hit the refresh button and i no longer have the the base map i'm also going to do the same thing i can see the rivers are actually overlapping my area i don't want to see them need to go back to kgs remove the river so you can only have this data here so i'm going to just go back to the other side hit the refresh button again and now we have remained with the map and the sample locations now the next thing i'm going to do is i'm going to have it have a very nice frame so i'm going to scroll down on the item properties put it give it a frame so after adding the frame i'm going to add the other elements so i'm going to add something like say the grid into another grid and in the grid i want to modify the grid and i need to leave them as solids for the x interval i'll say 5 000 because it's utm by maybe 5 000. the x and the y then the next thing i'm going to go to is the line style i can change the line style if i want then the blending mode i can change it if i want then the frame i'm going to say maybe exterior ticks i want to have exterior ticks then let me just zoom in to this map first but you can just work on everything every element in this map then we're going to introduce all the other maps dramatically so i'm going to move them up down a bit leave some space for the grids then i can now remove and say maybe frame annotations i don't have the grids interfering with whatever information i have here so then we're going to be adding the coordinates so i'm going to say draw coordinates and you can see it has drawn the coordinates and it's in decimals so you can actually change them to even custom but i'm going to leave it as decimal then the left segment which is this side i'm going to make sure that they are vertical ascending and also for the right side i'm going to make sure that they're also a vertical descending it just should use a vertical ascending then i'm going to can see it has the decimal places the values so i'm going to just change the decimal places to maybe say in another position i'm going to make sure that it's to maybe one decimal place okay then that is it about the grids you can actually change the fonts the size and all that i'm actually not going to customize much of these grids because this is just for demonstration then the next thing i'm going to do is i'm going to add another arrow so add then add node arrow then i'm going to add another arrow here then i'm going to you can actually add the scale you can actually add the legend i'm going to add the legend and this is mercury so i'm going to remove everything else from view by making sure that i uncheck the auto updates then i remove everything else then i'm going to customize that to mercury concentration in you can actually put the units [Music] milligrams per kg and i'm going to resize the the legend so that it fits nicely by i can even remove the project survey area because it's not really necessary i just move it and put it somewhere nicely on my map so that is the mercury concentration of milligrams per kg so the next thing i'm going to do is i'm going to now create the other maps which are around i think let me see one two three four eight eight maps so we need to create eight more maps of the same so i'm gonna select i'm going to select this is a fast mark copy and because you're creating eight more maps so i'm going to just also do the same thing again i'm going to paste another one again and i already have now three maps one is actually overlapping outside but i know how to fix it later on so i'm going to select the three maps then i'm going to click on group then i'm going now that they are grouped i'm going to copy then pests and you can see i have preset another group of maps here three maps here so we have now one to six maps we need two more maps so i'm going to also paste again and we have some other maps here and i'm going to actually delete one map or i can leave it for the insert but it is not a problem so i have now nine maps but i want to delete one so i'm going to ungroup again first then i'm going to delete one of the maps but i have only eight maps then i'm going to group them again all of them now and select all of them then i'm going to group them and they are now in one group then i'm going to just resize them as to fit into my pop canvas after making sure that they have actually fitted very nicely into my work canvas i am now going to ungroup them but i no longer have them grouped and now each and every map is independent on its own the first map was mercury so i'm going to since i've already finished working with mercury i'm going to lock the styles of mercury so before i do that i'm going to go to the other side and check the heavy metal concentration so that i just remain with now the interpolation results then i'm going to come to the other side i'm going to click on refresh and you can see all the maps now change to the same but now we want each and every map to be different depending on the kind of heavy metal that was investigated in the area so i have already i'm already done with the mercury concentration i'm going to click on lock layer and lock style then i'm going to now go to the next map here which is now going to be a scenic so what i'm going to do is i'm going to go back to my qgis and i'm going to change try and check mercury and i'm going to check ascenic and i'm going to style ascenic first so to style it i'm going to go to properties then i'm going instead of a single boundary scale i'm going to say i want single bands to do color and you can see now the range of maximum and minimum are different from i don't know mercury i'm going to use the discrete also and i'm going to say instead of i'm actually going to also use the same same color that we used in the previous metal which is a concentration then i'm going to say should be equal interval and i'm going to change the classes to six classes so after that i mean click on apply okay and we have a result for ascenic so what i'm going to do is i'm going to go to the other side of the qgis and composer i'm going to hit on the refresh and you can now see it has changed all the other maps apart from the one for mercury so you can see like for example there's a big blue dot here and there's none here so we're going to now have this as a scenic i'm going to click on the dot arrow copy then paste it and then i'm going to move it there very nicely then i'm going to now create a legend for arsenic so i'm going to go to legend i can even copy this legend and pass it there and it's still saying mercury i'm going to change it so instead of mercury i'm going to click on add and i'm going to say ascenic then okay then i'm going to remove mercury and now i have a scenic and its concentration in milligrams per kg so i'm just going to say acidic concentration concentration milligrams per kg and i'm also going to remove the band so now i have a very nice legend for scenic so i'm going to go to the next map now and before i go to the next map now that i've already made for scenic i am going to select a scenic and then i'm going to lock the layer and also lock the style then i'm going to scroll horizontally and i'm going to now go to the third map which is now showing the values of ascenic but i want it to be another heavy metal so i'm going to go now to mikkel that'll be my third map i am going to add the sketch because they are of the same scale i am going to add the scale bar so that we can have one scale buffer for all the maps add item add scale bar another scale by here six and then i move it somewhere and i can also add some more information about these maps including a table that just shows maybe which concentrations show high levels because it was the different metals they have different kinds of concentration but since i don't have that information right now then i'm going to add it you can also add some credits to the map and then finally the last thing you're going to do is now we're going to export this map as a jpeg or as a pdf so that we can be able to now look at it and include it in our report so i'm going to add it i'm going to save it as a pdf file go to layout i'm going to save the project first then i'm going to go to layout then export as image then i can export it in my distribution map exercise i can create a new folder call it maps then this is my first draft so distribution maps map 1 and save then i'm going to leave it at 300 dpi but if you increase the dpi then the map becomes clearer and clearer let's save it like that i can actually look at the map that i have just saved i can see we now have all the maps required for reports including all the elements like mercury ascenic nickel zinc cadmium chromium lead and copper and you can actually see now the different levels of concentration in the different areas that's it for today's exercise if you found this video useful and you want to learn more on kjs subscribe to my channel don't forget to give this video a thumbs up otherwise i'm just happy you're here see you in my next video 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Channel: WiseGIS

Views: 384

Keywords: qgis, spatial distribution, gis, spatial distribution map in qgis

Id: KmVxoywMrek

Length: 27min 18sec (1638 seconds)

Published: Wed Nov 03 2021