Making a Geological Map using QGIS

hello guys welcome to another tutorial in this tutorial i'm going to show you how to create a geological map just like this for pretty much any region in the world by making use of freely available geological data that you can download from the website of united states geological survey so in this tutorial i'll be showing you how to download the data for free how to filter out the gis data that we do not really need and pick the information that would be relevant for your specific study area and how to transform the information into a presentable map like this with the help of an open source js tool like qgis so without further ado let's go ahead and get started with the tutorial alright to get started you can simply google world geologic maps usgs and you'll find this searchmapper.cr.usgs.gov web link through which you can access this world geologic maps and once you open that up this is how it's going to appear and from here you can see that we have access to download the geological maps of different parts of the world in gis formats such as shapefile so for example if you are interested in let's say downloading the geological maps corresponding to asia-pacific region you can quite simply download the generalized geological map of australia and new zealand as well as the generalized geological map of southeast asia and not only that you will also get access to information such as faults and tectonic contacts so for this particular tutorial i'm interested in the european region so what i'm going to do is i'm going to come right over here and i'm going to download this generalized geology of europe including turkey as a shape file so just click right over here and you can see that the file is getting downloaded in addition to this i would also like to download the shapefile which indicates the faults of europe including turkey so in addition to this i'm going to go ahead and download this one as well all right so as you can see both the files have been downloaded already and that was basically these two files so i'm going to extract these two files into my working folder and also this file which contains the information of the false i'm going to extract it to here as well and now let's open up qjs because we are going to create this map using qgis and after that we can navigate to the place where we downloaded our files into and that was this making a geological map folder and right over here you can see that we have those two zip files actually we can get rid of those two zip files because we won't be needing them anymore and first i'm going to drag this generalized geology shape file into my working space simply drag it and drop it over here and from here you can see that it's quite a complex shapefile consisting of a massive number of polygons and if you're a bit confused about the orientation you can see that uk is right over here and if you would like to have a look at the attributes of each of these different polygons that you can see over here you can either take this identify features tool and you can just click on the corresponding polygon that you would like to inspect and from here you can see that we have a couple of different attributes over here we have the area the parameter and we have some ids and also we have one attribute called glg however rather than going one by one if you would like to get the attributes of the of this entire shape file you can simply go over here to this layer right click and you can open the attributes table and from here you'll be able to see all the different attributes in this manner i guess we are not really interested in this information but what we are interested in is this particular column that you can see as glg and over here you can see that it's using particular set of ids to denote different rock units so it's definitely helpful to know what each of these different uh ids actually mean but there are certain things that we can infer by ourselves for example whenever there is h2 i think we can infer those to be presence of water bodies and whenever we see the notation to be see it refers to the presence of the seas but if you'd like to know what these other notations actually mean we can head back to the world geologic maps web portal and for each of these different areas that they specify over here you can see that they link particular publication now since we are working with the data of europe we can scroll down and we can click on this entire publication and from here you can open up this short report now i have already downloaded this report so i'm just going to open that up and this is how that report looks and if you scroll down you will see right over here what each of those different notations actually mean so the notations that you saw are basically corresponding to these different uh sedimentary igneous and metamorphic rock units of different geological time periods all right so let's go back to qjs and get started with our map now if you would like to quickly visualize this map in terms of the different geological rock units you can change the symbology simply by going to the properties and over here you can select categorized and under the value you can remember that the different geological rock units were actually under this glg column so you can select that to be the value and over here on the color ramp we can make sure that we have selected random color ram since there were quite a number of different geological rock units and after that if you click on classify you will see that all those different values or in this case all those different geological rock units are actually getting classified in this kind of a random manner so random colors are basically assigned and if you would like to change that assignment for some particular reason you can again click over here and you can shuffle the random colors so the colors will get shuffled and if you click apply and now you can see that uh despite it looking a bit too complex now we can clearly uh distinguish between the different rock units just like this and and if you would like to pull up the information of a particular rock unit all you have to do is simply take this identify tool and maybe click on that particular rock unit and over here you can see what it refers to also something important if you haven't noticed until now you can see that the on the fly projection was not really able to pick the coordinate reference system that was assigned to this particular shape file so if i right click over here and if i go to properties under information over here that the coordinate reference system is detected to be unknown but we can still see some information right over here but i found that the version of qjs that i'm using does not really have this particular coordinate reference system 1984 lambert conformal conic projected coordinate reference system in its system so what i'm going to do is for the timing i'm going to change the coordinate reference system of my data frame to be web marketer auxiliary sphere coordinate reference system which is this one and i'm going to click apply and click ok and now to create the geological map i'm not actually going to work with the entire set of information that we can see over here instead i'm going to zoom in and pick a specific region now if you were to select let's say a landlocked country and if you happen to have the shape file of that particular country you can perform a simple clip operation in order to extract only the part of this geological map that you need for that particular country or the region of your interest and in this case i'm going to actually work with the this land mass that you can see over here which corresponds to the areas of republic of ireland as well as northern ireland and since it's bounded by sea i can do a quick selection manually without actually having to do a clip operation but in case if you were to extract a land area based on a specified polygon you can simply do that using a clip operation so for this case just to do a manual selection of this uh northern ireland and republic of ireland what i'm going to do is i'm going to click on this fly out menu under the select features and i'm going to pick the select features by freehand tool and when i have that tool all i have to do is simply do a freehand selection just like this just fully covering the land area that i need to select and now you can see that these yellow color areas are the areas that were actually selected uh in addition to this landmass you can see that even this even the area which represents the sea also got selected but that's all right later if we do not need that we can actually get rid of that quite easily so having this selected what i'm going to do is i'm going to right click over here and click on export and select save selected features as and the format i'm going to speak the format to be s reshape file and the file name after navigating into my working folder i'm going to name this as geology underscore ireland and you can see that automatically it'll have its extension in dot shp and the coordinate reference system what i'm going to do is rather than leaving this in this unknown crs i'm going to select this the same coordinate reference system which i selected for the data frame which was this uh 1984 web marketer auxiliary sphere coordinate reference system and the remaining information i'm just going to leave them as it is and we can simply go ahead and click ok and now if i deselect this main generalized geology of europe shapefile you can see that we pretty much managed to isolate the landmass that we need and of course i think we don't really need this area which demarcates the sea as well so what i can do is i can go to this geology island newly created shape file right click and click on toggle editing now all i have to do is open this fly out menu click on select features and select this particular polygon that we do not really need and simply hit delete and that should do the trick for you guys also if you open the attributes table now you can see that we have the different attributes out of which we i don't think i would really need to have this area perimeter and these two columns as well so if you would like to get rid of those four columns we can click on this delete field button just make sure that you have put this in editable mode before clicking on this delete fields button and after that we can simply select all the columns that we do not really need and click ok and after that i can click on this toggle editing button in order to save my edits and that should be it we can go ahead and apply a different symbology go to categorized and now the value is simply going to be this glg column and we're going to assign a random color ramp click on classify and you can see that a random color ramp got assigned if you click ok just like this well i would like to shuffle the colors just a bit until i get something that looks okay to me i think that should be fine and now even if you expand this you can see what each of these different colors are actually uh referring to well just for the water bodies you can see that this h2o is basically referring to these inland water bodies that you can see so i'm going to go back to the properties and just for that h2o maybe i would like to change the color well instead of having a color let me go ahead with the this kind of a hashed pattern and it's and for the color i would like to go with maybe blue color just so that it'll be a bit more representative just like this yes i think that's all right i think that's good enough and after that we can simply go ahead and click ok all right so now we'll see how we can put this information into a nice map layout so to open up map layout you can go to project and select new print layout and i'm going to name this one as geological map and click ok and the first thing that you would usually need to do is to set up the properties that are associated with your page size so to do that simply right click over here go to page properties and over here select the size of your page now for this i'm going to go with the page that's of the size of a4 well this depends on what sort of a page you are planning to print this map later on if you're planning to do that and the orientation i'm going to have a portrait orientation and once you're done with the specifying the page size and the orientation you can select this add map button and after that you can manually draw a rectangle demarcating the region of the page to which you would like to fit your map now either you can cover the entire page but i would like to add some additional information corresponding to the coordinates right next to the border that i'm drawing right now so for that purpose i'm going to leave some space between my border line and the edge of the pages just like this so that's the reason i have actually not covered the entire page so after you have specified this rectangle you can simply let your mouse button go and just like that the geological map appeared on my a4 sheet isn't it and if you didn't manage to specify the extent of this particular rectangle first time you can always make those changes manually afterwards as well so for this particular case i'm going to let's say manually specify my border to be like this and now i think you can notice that we still have some room to improve in terms of especially in terms of trying to get this geological map to fit to the extent of my entire page isn't it and if you try to zoom in you can see that the entire page gets zoomed in and out and even if you try to move this map you can see that it's not the map that gets moved it's basically your layout that gets moved so in order to access this map that's within this layout or within this border you can click on this move item content button and now if you try to move you can see that this border no longer moves but instead the content inside that bot actually moves and even if you use your scroll wheel now you can see that quite simply quite easily you can zoom you know you know out and as you do that you can see the scale over here changes so if you like to change the scale numerically you can do that as well instead of using the scroll wheel let's go with about 3 million yeah i think that's a bit too much i think this kind of fit is alright for me for the time being but late if i need i can make the changes without a hassle and finally to add a solid border to this map you can simply scroll down over here and click on this frame check box and that will add a solid frame to my map and you can increase or decrease the thickness according to your preference for example if you increase the thickness you can see that the thickness of this line increases i'm going to stick with the default value which was 0.3 i think that was quite all right and now let's add a couple of things to change this map just from being an ordinary map to a proper standard map and we'll get started by adding one of the key components which is the north arrow we can go to add item over here and click on this add not arrow and after that you can draw the extent of the north arrow right around here and as soon as you do that you will see that under this item properties you'll get quite a number of app symbols i'm going to click on this arrow folder and from here we can pick an image of a node error i'm going to go with this one i think that's good enough for me and after that you can adjust or rescale the size according to your preference i think i can make it a bit smaller and you can do further edits like change the the straw color and so on but i'm not going to bother with that for this particular tutorial and after that let's go ahead and add a scale bar so simply we can go to add item and click on add scale bar and i'm going to place my scale bar right over here and you can see that my scale bar initially is in kilometers and you can change that by going over here to the units but since this is actually covering two countries both republic of ireland and northern ireland i think it's better to not change this into a unit like meters because we'll be having quite a number of digits if we do that so i'm going to return the units to be in kilometers just a small adjustment i'm going to do i'm going to drag this just to increase the size of the scale but even if i do that you'll see that this size of the scale actually didn't change and that's because we haven't increased the number of segments that you can see over here now these segments are these uh colored and uncolored boxes that you can see over here and if you increase the number of segments you can see that accordingly my scale also increases so i think i'm okay with having about four segments and along with that you can actually change any associated properties as well if you wish to for example if you would like to change the height of the scale bar just like this you can do that but i'm going to retain the default value which is three millimeters and similarly you can do the changes to let's say your font if you would like to change the font color or the font size or even the font type you can simply click over here and you can change the size like this accordingly but i'm going to retain this to be about 10 and the color and the rest of the settings i'm going to leave leave them as it is all right next one of the key components that we need is the title so we can add the title of the map simply by going over here and we can add a label and i'm going to specify my extension of the label to be somewhere over here and the label in this case is going to be general geology of republic of ireland and northern ireland you can type that in over here and it'll automatically get updated inside your text box just in this manner and for this of course we need to make some changes uh to make the title stand out a bit more and i'm going to get started by clicking this font button under appearance that you can see over here and that'll basically give me the opportunity to change make changes to the font i'm still going to work with the default font type but i'm going to make that font bold and after that i'm going to increase the size to be about 14 and click ok and you might need to do some further adjustments just like this as well and the horizontal alignment we can click that to be center just like this i feel maybe it would be good to increase the font size just a little bit so i'm going to go go back over here and increase the font size to be about 18 and that looks a bit too much or maybe if i shift northern ireland to be on the second line i think that should be that should be good enough and while you're making these additions if you want to make any changes to the placement of this geological map within our frame you can always go back to this move item content button and you can make the changes accordingly and now i think you can see that we have the freedom of moving this a bit further up and why i'm leaving so much space over here i'm going to tell you just in a second because this map in this sort of representation is actually quite useless because we don't really know what each of these different colors actually mean so what i'm going to do is i'm going to add a legend and a legend is able to provide all the information about the the notations of each of these different colors so that we'll be able to see which rock unit is actually belonging to which particular geological period based on the notation that we have and to add the legend you can simply go to add items and from here you can select add legend and similar to what we did so far we can simply drag and draw the legend let's say somewhere over here and initially our legend is actually not going to be according to what we expect because it's going to be quite messy especially if you have quite a number of layers in your working space and over here you can see that in addition to having the information that we really need we have some things for example this layer which refers to the general geology of entire europe is still here and if there were other layers they will also be present and we'll have to manually get rid of those information as well and along with this general geology information since we downloaded a shape file which shows the fault lines i think we can import that information into the map as well so we can keep this window open or we can keep this window minimize for the time being and now i'm going to import this flt for underscore 2l this was the file name that was there by default so if i drag this and drop it over here you can see that it's basically showing all the fault lines of entire europe but i would like to have only the fault line which corresponds to just northern ireland and republic of ireland so what i'm going to do is sim similar to what i did before i'm going to click on this fly out menu i'm going to select features by freehand and make sure that you have clicked on this particular layer and after that i'm going to manually select all the fault lines that are inside island and after that i'm going to export and save selected features as and this time the file name i'm going to name this one as false island and the coordinate reference system similar to what i did before i'm going to select this uh web marketer auxiliary sphere coordinate reference system and after that click ok all right now i'm going to deactivate this particular layer and i'm going to make some changes to [Music] the appearance of the fault lines basically what i'm going to do is i'm going to increase the thickness of the line as well as the color of the line i'm going to make the color to be black and increase the stroke width to be about let's say 0.46 yeah i guess it's not too thick well if it is maybe we can decrease this to be about 0.4 yeah just a slight reduction and now if i open up this window again you can see that all the changes that we did over here has already been transferred into the map so whatever the workflows that we are doing over here is actually getting projected into our map layout right over here which is quite convenient and now you can see that not only the map got updated even the items of the legend got updated as well so anything that we do in the main qgis window is actually going to get reflected in this particular legend window as well as long as we have ticked this auto update button but in case if we haven't ticked this auto update button none of those change would actually apply into this legend window so after unticking this we can do the changes that we need manually for example if you would like to get rid of this this particular layer we can select that and we can remove that similarly if i want to get rid of even these fault lines entry we can simply get rid of that and we can have a dedicated legend just only for the different rock units now you can see that it's a bit tricky to actually fit this entire column into into my map layout and it would be convenient if i could split this column into let's say two or three columns and you can simply do that by scrolling down over here and under these columns you can increase the number of count but nothing changed yet because i haven't selected this split layers item and as soon as i do that you can see that my column got split into two layers well two columns basically and if i increase the number you can see that it changes accordingly but i guess i can work with two columns just like this especially given the availability of the space that i have over here and if i go back to this legend items and if i right click i can make this to be a group just like this and of course what's left is making some changes to the text we can go here to the fonts and text formatting and since we assign this geology island to be a group if you want to make any changes to this geology island let's say if we consider that to be something like a heading we can click over here and whatever the change that you do over here will only get applied to that particular group heading just like this and if you would like to change the text over here simply you can double click and i'm going to name this as geology i think that should be fine and over here we have one item that's actually not been assigned anything so i'm going to get rid of that and this h2o item i'm going to maybe move this down just like this and place it to be the last element because that's not really a rock unit but i would still like to keep it under this geology heading if you think that this is a a bit too populated maybe we can even try increasing the number of columns to be three instead of two i'll show how that would look yeah i think i i think that makes things spread out just a bit and if you go over here and click on this equal column widths then it'll make sure that it's having equal distances and similarly i would also like to add what these black color lines actually mean in this particular case and those are referring to the fault lines so we can go back and add another legend element and even though it's going to be messy at first well we can first take it over here and get rid of all the items that we do not really need first by disabling this auto update option and after that we can select the items that we do not really need get rid of them and i will place this somewhere over here right below this and of course i'm going to name the change the name to be and now if you would like to add a rectangle just so that we can bound all of these items of the legend to be a bit separate from the other areas of the map we can go to this add item and we can add a shape and add a rectangle over here and we can draw the rectangle just like this and of course my intention is to not have a fill color so i'm going to go to sample fill and from here under fill color i'm going to select transparent fill and that should do the trick for me but of course if you would like to have a light color as the background color you can do that as well but i think i'm going to leave it as it is and finally someone would be interested to know the coordinate information of uh of this particular area now for that well we can make a slight adjustment like this to apply the coordinate information what we can do is we can simply go ahead and add a grid you can select the main map window and after that if you scroll down you will see one option called grids over here and we can add a new grid and we can go over here to modify grid and now we have to specify the splits for x and y and that's basically how the grid will be drawn and something to keep in mind is that over here it's using the map unit which is in meters so you can basically get an idea about the distances by looking at the scale bar right over here so if you were to have a splits of let's say 100 kilometers then one of the if one of the lines were to be over here then the next line would appear somewhere over here so i think i would like to have maybe my splits in the x direction at distances 150 kilometers apart from each other and if i were to convert that into meters then i have to multiply it by 1000 so it's going to be 150 000 and for the y direction i would like to have the grids let's say at the same interval for the y direction it's going to be a bit too much and if you leave it just like this it's going to be a bit messy because now it's uh having the same color as this fault line so i don't want these grids to be that obvious so for that what i'm going to do is i'm going to again select this main map window go to grids click modify grid and from here i'm going to change the line style to be a dashed black line like this and i'm going to decrease the opacity of the line by quite a lot furthermore i'm going to reduce the stroke width as well and again i'm going to change the color to be a bit of a gray color instead of having black color yeah i think something like this would be fine but of course we need to add the numbers now so i'm going to go over here to this frame style and by default it's no frame so i'm going to select exterior ticks so what it does is it's actually going to add these exterior ticks to which we can link the particular coordinate number and to add the coordinates we need to click on this draw coordinates and that'll take care of having the the actual values but of course we need to make some changes over here as well now to fit this properly into the page i would like to flip this from having horizontal formation to a vertical formation so the left and the right sides i'm going to change this to be vertically vertical ascending and that took care of that and for the right side it's going to be vertical descending just like this and since we do not really want to have three decimal points over here what we can do is we can scroll down and we can reduce the coordinate precision to be just zero without having any decimal points and i think now it's quite uh informative in terms of the coordinates as well just one more small remark it's always a good habit when you are producing a map to specify what sort of a coordinate reference system that you are using because if someone is looking at this map for the first time even though it's quite helpful in terms of what it's trying to say they might not be able to understand what sort of a coordinate reference system actually these numbers refer to so as a concluding remark what we can do is we can go over here to this add item button and we can add another small label right somewhere right over here which specifies the system i can simply go ahead and add that particular information to my map as well and of course you might need to make changes to the the to the font size we can reduce that font size because it's just only a remark that we're adding which doesn't really need to stand out much and after you think everything is aligned properly we can go ahead and conclude the map and if you do a full zoom simply by clicking on this button this is basically the map that we came up with with the information that we downloaded completely for free from the usgs world geologic map web portal well to export this map all you have to do is go to layout and you can export it either as a pdf or i'm going to export it as an image go to your desired folder and i'm going to name it as geological map and simply we can of ireland and after that i can simply go ahead and click on save i'm expecting to have a bit of a high resolution so i'm going to leave it as 300 dpi and we can simply go ahead and click save and now if you go ahead and open that up this is how your map is going to look and you can zoom in quite well just like this without losing its quality because we exported it in a bit of a higher resolution and of course if you would like to refer to these keys that you see over here in the in the legend you can always refer back to the report where they clearly indicate the description of these different rock units and even you can try to merge them together into one attributes table and rather than displaying this key just like this you can actually have the the proper description in the map as well and i'm sure with what you guys learned today you'll be able to do that quite comfortably now so that's about it for this tutorial guys if you do have any questions regarding this process don't forget to add them down below and we'll get back to you as soon as possible so thanks a lot for watching guys i'll see you again with another tutorial

Channel: GeoDelta Labs

Views: 7,975

Rating: 4.986577 out of 5

Keywords: geological mapping, geological map cross section, geological map arcgis, geological map reading and interpretation, geological map qgis, geological map profile, how to make a geological map, how to make a geological map in arcgis, how to make a geological map in qgis, geological time scale, geological engineering, how to make a map using qgis, how to make a map, making a map with QGIS, making a geological map, geological map with qgis, qgis mapping

Id: mIIciEIdgs0

Length: 35min 13sec (2113 seconds)

Published: Wed Jul 07 2021