hello and welcome to a video tutorial on the use of QGIS for archaeologists this video tutorial is designed for those students currently undertaking the Diploma in archaeological studies at the Department of Archaeology and anthropology at the University of Bristol it aims to provide those students with a brief introduction to GIS and the use of digital spatial data but to also provide those students with a way of getting their recent survey work in particular the work done clift and down romano-british field system onto modern louis backhoe maps using QGIS we're using a program called in to joist or quantum GIS this tutorial is based upon Windows 7 PC rather than Mac version so for those of you using a Mac you'll have to adapt accordingly in a previous video tutorial I showed you how to download data from digipak and for the purpose of that tutorial and for this tutorial I've used the data set focused on Winterbourne medieval barn in South Gloucestershire but she may well have downloaded data relating to Clifton down once you've downloaded and installed QGIS we're going to open it by double-clicking the desktop icon and the one that you're after is says quantum GIS desktop when you install the program you'll find there will be an awful lot of it I con that have appeared on your desktop the one you're after as I said is the one that says desktop depending on the speed of your computer to take a while to load up and you'll be introduced firstly to this screen the first thing that should appear will be this thing that says QGIS tips now you can cycle through these tips by pressing next or previous and this box will always appear every time you start QGIS unless you click this little box here and it won't start up and start up screen I'm just gonna click OK to remove it and you're going to be introduced to this screen as some people may have more I conjure less icons at the top here depending on the default installation you can expand these or could track them according to your own desire and how like more screens to be laid out first thing to draw your attention to is this large white area here which is your map screens is where the maps you downloaded from digi map will appear when you ultimately load them in as I move the cursor around you will see that at the bottom these coordinates change accordingly and when you load up your maps eventually your coordinates will reflect something much more familiar to you which will be the British national grid next to this coordinate box at the bottom you have scale which is fairly self-explanatory but you have the option to select a series of scales or if you want you can actually color it blue highlight it blue and just type in what you want okay the last box on the right hand side that I want to draw your attention to is current CRS wgs84 this thing at the bottom EPS g4 36 when you hover over it it gives you as I say current CRS wgs84 current CRS stands for current coordinate reference system and at the moment is set to wgs84 which is the world geodetic system of 1984 which you may remember from our class that is very useful for GPS because it takes the ellipsoid shape of the earth into effect what we're trying to do here with GIS is transformed something as three-dimensional as in the shape of the world to represent it in two dimensions to go onto a map the way we do that is through projected coordinate systems now I'm going to make a judgment here that the majority of you are going to be focused on the archeology of Britain in which case we're going to change these settings to automatically default to the British national grid for those of you who are interested in working abroad you'll have to seek out the local grid reference system for the places in which you're interested in working but for today for this tutorial we're going to focus on the British national grid so the first thing we're going to do once we start Gigi is for the first time is to go out to the settings option and then down to options and in here you have a series of tabs these things are the topical tabs and they all have various options in them and you can play around with these to your heart's content I'm going to lead most of these are default but the one that I do want to change is this one here that says CRS coordinate reference system and you'll see at the top here it says default coordinate reference system for new projects always start new projects with this CRS and in this case it's wanting wgs84 this epsg is a Authority idea like a shorthand code think of it so what we want to do is now change this wgs84 to the British National Grid if you remember back to class there were two triangulations undertaken in britain the most recent was undertaken between 1936 and 1953 and is known as the Ordnance Survey of Great Britain data 1936 and it's important because all modern base maps from the OS are derived from this triangulation so what we want to do is select that coordinate reference system so to do that we're gonna go to select you'll see here that I already have it in place for you who are starting this for the first time won't have that there so what you have to do is to go to the filter option and you want to type in OS GB and what it's going to do is filter out all the coordinate reference systems of the world for which there are hundreds here and it's going to give you a list of ones to choose from and we are after a projected coordinate system we're not after a geographic one we're after projected and in this case we're going for OS GB 1936 British National Grid and it has this Authority ID to 7700 okay but the main thing you're after is this British National Grid highlighted blue with one click say ok that's now stuck there well I'd also like you to do is every time we load up a new layer I want it to automatically default to the British National Grid as well so I'm going to click on this use default CRS displayed below the black so there's a black dot inside the circle and we're gonna do the same process again select find the Ordnance Survey 1936 you don't have it in here type it into the filter and it'll appear at the bottom and then say okay but you'll notice that at the very bottom right nothing's actually changed it still thinks that it's WG as its form well I want you to do now is actually close QGIS down and I want you to reopen it and what you'll find when GJ is ultimately reopens is that bit of that the bottom we now have epsg to 7700 a matter is the British National Grid and that means every time that you load up QGIS it is automatically going to default to that from now on it also thinks that everything you're going to load in wants to be in the British National Grid coordinate system right so then little introduction to the screen this is your map screen as I said before where your Maps going to be displaying you can see that as I move around the coordinates still change and the scales are still there when I click on this white box that now highlights blue its called layers and in this layers box is going to appear the files that you downloaded from digi map their file names it's going to appear here and you'll be out of order these so the ones on the top will be the dominant one so they'll be the ones you can see and in order to see the ones that will appear beneath it you either have to move them or turn them off in the same way as if you had a real paper map and you put that on top of another paper map the one underneath you wouldn't be able to see it works exactly in the same way as it does here at the top of the screen you've got various file menus these are the same as you have for things like words or Adobe products where you click on them and they give you a series of other options I don't need to panic too much about the quantity of icons and things here a lot of this you won't need to use in the course of your work one of the things you may want to do though is just adjust this screen to provide you with all the toolbars that you will find of use you'll notice that along here these things are all currently grayed out and if I get to this before arrow here and I click down it presents me with more options same options are bad but essentially it's saying within this little toolbar from here to here I've got more options that same here same here it could be that you want to move some of these so that they are instantly accessible to you and to do that you could do click on these little speckled areas here one click and hold move and you can have them downside you can have them up there it's entirely up to you how you want to do it and when you move the round they will expand some of these icons should be familiar to you so you've got things like and start a new project open a project save buttons print down the bottom here you've got pan you've got zoom in and out you've got the refresh button but some of the others will be less familiar to you but we'll tackle them in a short while before we progress and start to load up our data the first thing we should do which is good practice is to save the file so I'm going to click save and I'm going to call it winter born barn I've already prepared one before but I'm gonna overwrite this and you just type any name that you want whatever you're doing as a file name and just click save wherever you want to save it on your computer I now have quantum GIS 1.8 wins for God you could create as many projects as you want you can have projects for every different essay you did or as one for your dissertation once you field work report entirely up to you ok so now that you've got an idea of the screen and the icons and you've managed to move some things around we're going to load some of our data that we downloaded from teaching that when we use the previous tutorial download is did you map data we downloaded raster data and if you remember raster data is nothing more than image files so a JPEG a test fit map they're all raster data the raster there is nothing more than an image so if you were to go out with a digital camera take a fit picture download that to a computer back to rasa teach if you were to take in a Ras aerial photos somebody from English heritage sent you all or scan a Ordnance Survey 1 to 25000 map onto your computer that's um the image it's made up of a series of colored blocks called pixels the more pixels you have the better the quality of the image so the data that we're going to be making use of today is going to be raster now normally raster data has no geographical information on it it's something you have to assign in a later point and that's a technique I'm going to show you in a little bit how you could take for example an aerial photo or maybe in your case at earthwork Survey and put it over a modern Ordnance Survey map first of all we're going to load up data that has somebody somewhere has already put your ethical information in to do that we're going to load raster data and at the top you would be series of icons and the one I want you to go to this one here if you hold your mouse over without doing anything it will come up with addressed and layer then I click on that now I want you to go to wherever you store the stuff you downloaded from DG map and I'm going to start by going into the raster fifty-thousand when I go into this folder you'll see there are three file types and one that I'm interested in is this one that says TIFF TIFF is a file format for a raster image you may have come across tips or JPEGs before so what I'm going to do is I'm going to highlight it and I'm going to say open and now you can see that a map has appeared on the screen and one to 50,000 map and if you use some of these icons here you can zoom in and out okay down to Thornbury you can draw rectangles to zoom in and out this option here little hand allows you to pan you can zoom to its maximum scale you can refresh the map there's a few other things this option here allows you to measure see measuring in kilometers on the left hand side under the layers you'll see that it's giving you this file st 68 and that's this entire square that you can see here it's called st 68 because it's the first one we loaded up we know we loaded one per 50,000 to make this all a little more organized we're going to create folders into which we're going to place these grits these little tiles so do that I want you to right click on the white anywhere and add new group and in this case I'm going to call this 50 cake click anywhere again and you'll see we now have two different folders one looks like a folder one you can still see a little thumbnail of this what I want you to do is just highlight with one left click on here and then just drag hold the left mouse button and drag it down and what you're looking for is the small short blue bar the long blue bar will just place it underneath here that's placing into the 50,000 you can see goes to that and then down into that so what we now have is a folder that says 50,000 so if I turn that off disappears and it back on that's my one to 50,000 map what we're now going to do is load up more data the one to 25,000 one to 10,000 and the master map data and we are going to give groups to each of them so let's go through this again address the data back to where you found your wherever you store to your data into 25,000 SC 60 80 notice something here file names are the same even though they're two different Maps and this is why you want to add these groups otherwise it will become very confusing add new group in this case 25k drag back down and I'm going to put him underneath what we now have is 50k and 25k I'm going to do the same for 10,000 see how the 10,000 has appeared here because it's at the top its appeared over the top of the other ones that are underneath it so it's now dominant but good reason you can see the rest of this stuff round here is we only download the dry only down into the tile for a small area do that again add new group 10k and I'm going to take that in if I drag this right to the top and they go one of the things I want you to do is to make sure you can order these according to your own ways of outdoing Maps how you feel most comfortable so ensure that when you move these that it updates the image to go on top if you right-click on any of these and just click update drawing order it'll automatically refresh the map when you move these folders up and down okay so you've got these three and now we just want to introduce one more set of data which will be the master map and here we have four tiles for TIF files that we're going to add and you'll notice them appear in green see you right down here and again I'm going to add a new group and call the master map and I'm going to put morning remember short bath drags them in in fact the top so what you can see here is we've actually got the one 250-thousand you've got a 125 thousand occurring here just a backseater one to ten thousand there and in here you have the master map but actually we're too far doing that for any of this to be any use to us so what we want to do is start to zoom in just the normal class size well actually even as we zoom in somebody's not particularly useful as you can see on the right hand side the one to 25,000 map to this is alright at this scale which is one to twenty seven thousand nine hundred Nate will change that something more sense let's go on to 25,000 so that's okay but there's 1 to 10,000 and this master map they're pretty much useless at that scale so if you don't want them what you can do is just turn them off like so and they'll disappear and you're left with 1 to 25,000 but a much more cunning way of using this is to set what are called scale dependent disabilities that means that these maps will only appear when you zoom in or zoom out to a particular level so what we're going to do is set a scale dependent visibility for all of the tiles that we've loaded up to do that unfortunately we can't do it by clicking on the folders the groups we have to actually go into each individual one so what I want you to do is just go in to highlight one blue just double-click it ok with your left mouse button and you'll be brought in to a screen like this and I want you to go to the tab at the top that says general down here you have what's called scale dependent is ability click it and then you're going to set a minimum and a maximum scale so I'm looking at master I don't want master map to appear beyond 1 to 2,000 once it gets beyond that from my perspective you can't see things clearly so what I'm going to do is set a maximum of 2,000 I'm going to do the same with the others and you're seeing on the screen the little tiles all disappearing okay you can see on the right-hand side you still what we won to 25,000 and here this is the one to ten thousands of blue and green so I also want to set the one to ten thousand the way I do this is I set the minimum scale of my next there's one to ten thousand as what the maximum was of Master Mac the maximum mass maps 2000 and I want so I set that as the minimum my maximum in this case is going to be ten times twenty five thousand I'm going to do the same again so I'm going to start at minimum at what was the maximum of my previous which was ten thousand I'm going to do a maximum twenty five thousand and the same of the fifty thousand fell to him at 25,000 and I'm not going to give him a maximum at the moment you could do a maximum if you had the one to two hundred and fifty and there whatever what you'll find now is these little minus buttons allow you to close them all up as i zoom in you'll see the backs changed to them the one to fifty thousand to the one to twenty five that's now changed to the one to ten thousand still want to turn now into the market in that data you don't have to change this tool now but the one thing you do have to do good procedure save it click the Save button and that's also the next time that you load up to you is and you load up the file you're using you will have the scale dependent visibility set and now's an opportunity for you to pause this tutorial have a play around use all of these as like ons see what they do pan and scale look at the coordinates set of scales and just get familiarity with QGIS and when you're happy come on back okay welcome back well why now you should have played around and got some familiarity with QGIS we're now going to do some more sophisticated stuff which is we're going to georeference images that do not have their own spatial information onto these base notes using these base maps ad to determine locations the process known as geo referencing and it's particularly useful if you are in your case stand and made available your web surveys or if you've got an RAF photo or another type of aerial photo that's coming the Sheraton or you scan the tithe map or something you could get them to overlay directly on top of an existing base map in order to accomplish this what we're going to do is we have to turn on a plugin now plugins are an additional tool set available to you that are designed by various people around the world remember QGIS is not designed specifically for archaeologists and lots of people have designed lots of different bits to it that don't necessarily come in pre-installed with the package you kind of pick and choose them as you want so what you need to do to go up to plugins and then you want to go to this option that says manage plugins and as you scroll up and down you'll see that you've got all these things here called plugins and there are a couple of things that will be of interest to you here and the first of these as you scroll up and down is this one here that says geo-referencer gdal and i want you to click on it so that it's got across my door going across because I've done it before another one that'd be quite useful for you is if you scroll down click on this open layers plug-in as well and that'll allow you to load up Google Maps beam map layers over the top of this at a later point say okay nothing in this terms on the screen has actually happened but if you go up to raster you now have this option that says to your reference er what I would like you to do is just hold your mouse over to your references so it turns blue and then hold your mouse over the actual words geo-referencer and click it once and it brings up this screen what's going to happen is we're going to make an image up here in this screen and we're going to assign it geographical coordinates by clicking on one point from the map on the image that's the same as a point on this map to do that we're going to load it up first so here we have an open rest of this this little icon you should get familiar with you click it what I'm going to do is you can see I've got this aerial photo you see the thumbnail here I'm just going to open up what I've got is this aerial photo that's appeared you can see this road comes up branches around to the right to this road here what I would like to do is to assign coordinates for some of these locations so I overlay this aerial photo onto this map to do that just going to zoom in a little bit now when I'm in a correct position I then click on these little dots here add points now I'm going to do this roughly the more precise you are the closer you zoom in and the more points you use the better your geo referencing will be but just for an example I'm going to show you I'm going to put a point here and it brings up this box when I click it the left click it brings up this box if you know the coordinate for that corner of the field you could type them in here if you don't you can say from map canvas that removes the little box you had before and all you have to do is with this go to the point you think it is click once brings you up with a coordinate and if I say ok you'll see a little red dots appear there and the little red dots appeared there but to do this two more times because I need three so I'm going to put another one in here from map canvas which I think should be here and I'm going to do it one more time she's going to be here so I've got three points and you can see them here 1 2 3 1 2 3 what you would want to do as I said zoom in a little closer on both maps and be much more precise in where you position them well when you're ready to go you got to this option here this start geo referencing and it's going to bring you up with another screen transformation type soon okay and this comes up it should have transformation type for liminal one leave it as is don't touch if it isn't turn it to it otherwise leave that leave that the only thing you're interested in on this screen is this thing that says output raster because this is where you're going to create a new file going to essentially copy this but it's going to copy it with geographical information in it click on that and then I'm just going to call this winterboard AP say ok save ok and there we go your aerial photo has now overlaid over the top of your map I'm going to close this down it's going to ask me if I want to save these points these these little red points you may choose to save them because if you find that you haven't quite got your geo referencing right you can load them back up move them a bit and it'll is that the image into its correct position for you but I'm going to ignore that for a moment so what I have here is an aerial photo I can turn on and off and you can see vaguely it's pretty much in the right location now I'm just going to run through them again by doing something else which is I'm going to zoom in close here you can see that as we zoom in I'm coming a little bit closer to the barn this is the barn here 14th century tithe barn with matter house stuff caught fish farms all around it from the moment I'm just going to turn this Winterbourne AP layer off and I'm back to the master map dator I'm just going to zoom in again a little bit more what I'm going to do here is I'm going to georeference some geophysical surveys that I did so to do that we go through the same process we did before raster to your reference er to your reference I go up to an ad raster geophysics and here I have two which look the same when I hold over it one of them will be a bitmap and the other one is jpg and the one that I'm after is the jpg for whatever reason the bitmap doesn't seem to want to work in QGIS so I've transformed it into a jpg and up it comes like this now what you're going to find is when I do the geo referencing there's going to be a black outline that comes around this and that's because if you can see I'm going to put it around this part of the barn here but the image itself should be rotated in this direction to be facing North North is that way but in this image it thinks it's going up that way so what you should really do is prior to doing this go into Photoshop or something and just orientate it as close to the north direction as you think it should be but for the purpose of today's tutorial I'm not going to do that said what I'm going to do is I'm going to click on some points again so I've got this highlighted I'm going to click here pick from map canvas should be this here okay this bit of mind is here map canvas okay and I'm going to go for this point here from map canvas that point there the more you do remember the better the quality the closer you zoom in the better the quality more precise you were trying to be the better that your geo referencing will be same process again hit the green bug setting output raster name which is this okay and I'm just you can call it whatever you want I'll call it winter board geophysics save say okay and there we go we have geophysics overlaid on top of the modern Ordnance Survey mapping now I can put the area aerial photo on underneath and they'll have that over the top sort of saying about this black area that's because I didn't orientate this image appropriately the first time so what is good is what I should have done is in Photoshop orientated the image so it was already facing this direction so that's how you geo-reference you can turn things on and off you can see that they overlay pretty pretty well and in this case we've got filled rain we've got possible building here going underneath the bar and importantly we have this here which I suspect is a moat or the outlines of a moat certainly one of the fields over here is called great moat field so it looks like the medieval Bard and possibly its manor house and its dovecot we're all noted come towards the end of this tutorial but there are a couple of extra things I need to show you before we finish first of these is you don't have to keep turning things on and off or setting scale dependent visibility if you want to see two things at once for example you may want to actually see what the underlying base map looks like with the aerial photo over the top the way to do that is this is the aerial photo that we do reference before this is it here in its file on the left hand side if I double click that I come into the same screen you were used to before with scale dependent visibility with a finger after at the top is transparency because I can make it partially transparent so let's go for say let's go 40% also say ok and there we have the AP has been made partially transparent is given the 40% transparency and because of that I can see what's underneath and that's a particularly useful tool if you're doing map regression techniques because what you can do is download the Ordnance Survey historic map data from digi map and you can also get hold of say ties maps or surveyors Maps with state map scan them yourselves go through the geo referencing process and you can actually then set transparencies for each of these things so you can actually see the Ordnance Survey map over the top of the tide map over the top of an estate map and you have to just play around with what you want in terms of settings and how much you want so that's geo referencing process of getting your stuff onto GIS so that you can now print this out and that's the penultimate thing we're going to look at very brief look at how you print imagine you want to print this screen you've done all your work you've got your geophysics on all you've got your earthworks survey on what you want to do go to file you can save this image which will save the screen but actually you might want to add things in such as scale bars and North arrows to do that you want to go to new print composer click on that and you'll be brought up with this screen something similar you want to add in a map first of all so you want to go up to this it should be familiar with this add a new map then all you do you hit it one and nothing happens what you have to do is just go to the corner of the screen and just hold your left mouse button and drag and pull let go and there it appears okay now you can say well why do I need to I could just print screen indeed you could but here you've got some tools that are quite useful for example we have up here scalebar so what I can do is go down to here put a scale bar so in this case I've given it a 200 100 meter scope bar but you can adapt this accordingly and it will it will change as needed you've got different styles of scale bar and you can play around with its height and swits and you can also use things at the top here to add in arrows you can add in North arrows you can add in labels if you wanted to point at a particular feature and add labeling you can do all of that up here and when you're ready you've got a few options you can either print it directly you can save it as a PDF or you can export it as an image so if we click exported image brings you up to another type of screen you should be familiar with at the bottom here you can cheat saving the file type I'm going to go for JPEG and I'm just going to call it WB beef Winterbourne barn save as or just save and it's doing its stuff and we should find that in a moment it will have saved and output that to your folder before we go and have a look at actually one have a look at that now let's go to that into one barn I've coming to my folder my AP in there's got the original AP and here W be beach or just output there we go with the scale I just said if I want to know if our and everything you'll be on there and that is now a JPEG which you can incorporate into your documents for your field field report just before we finish the last thing we're going to do is just show you how to make use of that loop and layers plug-in we use before nowadays you take go to your plugins go to open layers and because you've clicked on it in the manage plugins before you can now select them so if you want you can set any of these layers for example google satellite lair and there we have Google's satellite image uploaded now that's going to conclude our tutorial on QGIS and I hope you found it useful you can now go and make use of that for your fieldwork report and good luck
