Lesson video

Hello, my name's Miss Gilliat and I'm going to be your Geography teacher for today.

In today's lesson we are going to be learning about the features of an OS map.

So our lesson outcome for today is that you can use a key on an OS map to identify features and land forms. We've got five keywords for today's lesson.

The first one is scale.

So the scale on a map shows what size the area that is represented in the map really is.

Ordinance Survey or OS for short is the National Mapping Agency for Great Britain.

A key explains what the different symbols or colours used on the map mean.

Compass is an instrument used for navigation and orientation that shows direction relative to north, east, south and west.

And topography is the land forms and features of land surfaces.

Okay, so these keywords are in bold throughout the lesson if you need to refer back to them.

We've got three learning cycles.

So we're first of all gonna look at what the Ordinance Survey maps are.

Okay, then we're gonna look at OS maps at different scales and then we're gonna focus on OS map symbols.

Now the Ordinance Survey or OS is the National Mapping Agency of Great Britain.

They have been mapping Great Britain since 1791 and a person who creates a map is called a cartographer.

So can you remember, when did OS start mapping? That was in 1791.

Well done if you remembered that.

Now OS maps shows lots of different things.

So we're gonna go through some of the main features that they show.

So OS maps show directional information.

Now on OS maps, they will have arrows on them to represent which way is north.

And just to confuse you, there's three different types of north.

So there's true north, which is the direction towards the North Pole, grid north, which is the direction of the vertical grid lines on the map.

And magnetic north shows the direction of a compass needle points.

Okay, so that to it points towards earth's magnetic field.

Okay, so there's a little snippet of an OS map here.

So you can see where the three north arrows are pointing towards.

OS maps include the scale of the map as well.

So the way that they do this, there are usually two different ways.

The first one is that there should be a ratio at the bottom of the map.

So we can see here the scale of the map is one to 25,000.

That means that every one centimetre on the map represents 25,000 centimetres on the ground.

Okay, but often that's a tricky unit to work with.

So you might have to convert it into something which is more manageable.

So for example, 25,000 centimetres is 250 metres.

Okay, there will also be a scale bar at the bottom, so we can see it there.

And basically that shows how many centimetres on the map represent a kilometre.

Okay, and that can be quite a good quick way of just kind of getting your bearings, looking at a map, seeing how large an area is.

Maps use symbols to show physical and human features.

Okay, so if we have a look at the slide here, we've got a key which shows what the different symbols mean.

And then you've got an extract of an OS map there of Rhossili beach, okay, which is in the Gower in South Wales, okay? So all OS maps will have a key with these little symbols on.

Now the reason for that being if you tried to label all the different places on an OS map, it would be too crowded.

So a key and map symbols make it easier to read.

Okay, so let's check what we've just learned.

Why do OS maps use symbols to represent human and physical features? So this makes the maps easier to read.

Each OS map has a key to show what the symbols mean.

If all the features were labelled, the map would be too crowded, well done if you got that right.

Topography is the shape of the land and the landforms on it.

OS maps show the topography and height of the land through contour lines.

So if we have a look on the slide here, we've got a little snippet of an OS map and those faint little orange lines are the contour lines and they join up areas of the same height.

Now if you have a look, you will notice that some of those contour lines, not all of them have got numbers on them and that represents how many metres above sea level that contour line is.

So for example, there's one on the left which is quite obvious, which says 750.

So if you were stood anywhere along that contour line in real life, you would be 750 metres above sea level.

Okay, so those are the contour lines.

You've also got spot heights, which are black numbers located on a map.

They will often be put on the tops of mountains and hills to show how high that mountain top or hill is.

Okay, so for example, we've got two mountains here.

One is 893 metres above sea level and the other is 942 metres above sea level.

Also, some maps will have something called triangulation pillars or trig points for short on them.

Okay, now in real life if you go to where there is a trig point on the map, there are often concrete or stone pillars with a little number on them.

And that number again represents how many metres above sea level that trig point is.

Okay, and again, these tend to be located at the tops of mountains and hills.

Now OS maps can also show locational information, which helps us locate places.

Now you will notice over the top of an OS map there are faint blue grid lines.

Now the ones that are running horizontally across the map are called northings and they tell you how far north or south you are and the ones that are running vertically are called eastings.

So they tell you how far east or west you are.

Okay, now you'll notice that on the bottom and the side of the map there are numbers.

So that's represented on the map on the left.

Now it's a bit hard to actually see them because it's zoomed out.

But yeah, along the side of the map you've got numbers at the bottom of the grid lines and actually often the numbers are put on the grid line as well.

Okay, now these numbers help you come up with a grid reference to help you locate places.

Yeah, so the grid numbers are repeated across the map and can be used to locate areas.

Okay, let's check what we've just learned.

What are the arrows pointing to? So A and B, what are they pointing to and why do we use them? So A is pointing to a northing, B is pointing to an easting and why we use them, the northings and eastings, the blue lines are repeated across the map and can be used to locate places.

Well done if you got that correct.

Okay, so we're onto our first task for the lesson.

What I'd like you to do first is label these features of an OS map onto the one that you've got on your worksheet.

Okay, so pause the video and can you locate some of those things? Okay, let's go through our answers.

So first of all, you should have labelled a physical feature on the map.

Now the one I've labelled here is the beach, which is the yellow colour on the key.

Okay, another feature you should have labelled a human feature.

So I've labelled a camping caravan park there, okay, we've got the north arrow at the bottom, grid reference number, which is on the faint blue grid line, a northing, and you might have labelled a different one, that's fine.

And easting, again, you might have labelled a different vertical line but that's absolutely fine.

And finally the scale bar at the bottom.

So well done if you manage to spot all of those.

Okay, we're moving on to learning cycle two, which is looking at OS maps at different scales.

Now the Ordinance Survey produce maps at different scales and these different maps can be used for different purposes.

So we're gonna look at different examples and what they can be used for.

Okay, so the first one here, we've got an example of a small scale map, so it's quite zoomed out and here we can see the whole city of Birmingham and that little line there represents how long 10 kilometres is.

Okay, so it's a large area but not much detail.

Here we've got a map of Oakham, this is a bit more zoomed in.

So you can see some of the major towns features, some of the human and physical features and that black line represents how far one kilometre would be in real life.

And here we've got something called a large scale map.

So a really zoomed in map so we can see an area in much more detail and that black line represents there what one kilometre would be in real life.

So these are all maps produced by Ordinance Survey, but they're at different scales and they show different levels of detail.

Okay, so what I'd like you to do is have a look at those different three examples of maps at different scales and have a think, what would you use the different scales for? Okay, so why might you use a map which shows a large area but in less detail such as the Birmingham one and why might you use a map which shows a smaller area but in much more detail, have a quick chat with your partner.

Now larger scale maps like the one to 25,000 maps are useful when we need to identify smaller features such as paths.

So Aisha here has got an example of when she used one.

So she's put, I used a one to 25,000 maps when I did my Duke of Edinburgh award expedition.

So I'm guessing that she used that map to plan a route when she was doing the walking feature of her D of E.

The one to 50,000 maps show roads, large paths and some features, so are ideal when planning a day out, okay, so you might want to see what you can do in that area, the main roads that you would use to get to the area but you wouldn't plan, well you probably wouldn't plan a walk using this, you'd use a more a zoomed in map for that.

So Aisha used this map, she put I used a one to 50,000 map when I was looking for activities to do in Oakham.

Now the smaller scale maps such as the one to 500,000 are useful for seeing major roads and towns.

Okay, so here for example, you've got the whole city of Birmingham and the motorways which surround it.

Okay, and as Aisha has put here, "My parents use smaller scale maps when planning long journeys on the motorway." So this is useful to see where towns and cities are in relative to each other and looking at kind of long distance travel routes.

Okay, let's check what we just learned.

What would you use a large scale one to 25,000 map for? Planning a walk, well done if you got that right, and what would you use a small scale one to 500,000 map for? Planning a motorway journey.

Well done if you got that correct.

Okay, we're onto to our second task for the lesson.

We've got three examples of OS maps there all at different scales.

What I would like to do is explain what you could use each of these maps for.

Okay, we've got three answers here.

So for the first one, the one to 400,000, I would use this map to see the fastest way to travel around Birmingham.

For the middle map, I would use this map to see what activities there are to do in Oakham.

And finally, the one to 25,000, I would use this map to plan a walk from Ryton Lodge to Manor Farm.

Well done if you got something to similar to what I have put.

Okay, we're on to our final learning cycle, which is looking at OS map symbols.

Now one to 25,000 OS maps are useful for investigating the human and physical features of an area.

These features are represented by map symbols.

Okay, so can you recognise any physical or human features on the map? Okay, so look at that.

What human or physical features can you see? So you might have noticed some of the things that we have got in the key here.

So there's the beach represented by the sand colour, there was also a bunkhouse or hostel.

Okay, so OS maps have a key which help us identify different physical and human features.

Now you find different symbols depending on the scale of your map.

Okay, so if you have a small scale map showing a very large area, but in not much detail, on that map, individual wind turbines are not going to be marked.

Youth hostels are not going to be marked, but you might have things like motorways on there, okay? However, on a larger scale map you can show a small area but in a lot of detail.

So lots of different physical and human features can be showed on that map.

Okay, let's check what we've just learned.

True or false, maps always have the same symbols.

That's false, and can you tell me why? Maps have different symbols depending on the scale of the map.

Well done if you've got that right.

Okay, let's have another check.

So I'd like to use the key that I've got on the right here to identify some of the physical and human features that you can see on this Ordinance Survey map.

So can you see a bridleway? Where can you see a footpath, a visitor centre, parking, water and sand.

Pause the video and have a look for them.

Okay, so we've got a bridleway there, a footpath, a visitor centre, parking, water and sand.

Well done if you spotted those.

Now it's useful to remember a range of symbols so that you can understand the OS map more quickly.

Now I've got some of them on the slide here, not all of them, and it might feel a little bit overwhelming to try and remember these, but the more that you use OS maps, the more you get used to the symbols and can remember what they are.

So I want you to have a quick look at those and see how many of those different map symbols you can remember.

So pause the video and spend about a minute looking at those different symbols.

Okay, which ones can you remember? Right then, let's go through the answers.

So we've got a bridleway, a footpath, a visitor centre, parking, water and sand.

Well done if you've got those right.

And we've got a youth hostel.

The pink square is either a bunk house, camping van or other sort of hustle, a bus or coach station, place of worship, place of worship with a tower, place of worship with spire, minaret or dome.

Okay, and it's quite easy to get those different places of worship mixed up.

So it's worth spending a bit of time looking at those different symbols and how they are different.

Okay, we're onto to our final task for this lesson.

Now on the slide here, we've got a part of an OS map.

Now the blue line represents Aisha's walk that she went on, okay.

And on that line you've got numbers from one, two, three and four.

What I'd like you to do is in the table, write down what things Aisha might see in the section of the walk, one to two, two to three and three to four.

So look at the symbols and what will she see? You can use an OS map key to help you with this task.

Okay, so section one to two.

She passes a church, a post office, a pub, Low Mill farm, and a golf course.

Section two to three, a beach, a river, and a nature reserve.

And section three to four she passes Kelsoe Hill and North Farm.

You might have spotted another couple of things there, if you did well done.

Okay, so here we've got a summary for today's lesson.

Now OS maps use symbols to show human and physical features.

A key is used to explain what each symbol represents.

The details around the outside of the OS map give locational information such as the three Norths and symbols differ between a one to 25,000 and one to 50,000 map.

Right, that's it from me and I'll see you next time, bye.