G'day welcome back to Buildsum
what we're looking at here is the plan view of a building site and
You can see it's got these
random
curved wavy lines all over face. There's no real
now they're not parallel there are randomly spaced and
they don't seem to have any real purpose, but what they are
Contour Lines and
Generally, they're given a
number or a reduced level an RL and
basically what they represent is every point along this line
is the same height
so a Contour Line is or connects
points of equal height and
these ones actually given a particular height, so if you think about a beach
go the beach and you see the water coming in on the beach
You'll see that as the water comes in it'll finish at a height along that Beach
And it could be curved and in and out, but where that water finishes roughly is
all the same height and that's what you've got here is these contour lines if I was to put in a level
plane
everywhere along that line finishes at the same height
so you can see that there with a
level plane
so that's what the contour line is every point along there is is level and
They're given heights and generally that height is a standard distance apart, so if you look at these
Distance between this one and this one
That's a half a metre
Difference between there and there it's half a metre difference between there and there
That's half a metre difference between there and there now that's a difference in height not a difference in
length or horizontal measurement, it's a vertical measurement, so let me show you what that is so I'll go around the corner
So you can see between this point here 10.428 and
here the is a vertical difference of 500mm
same with the next two and
the next two so that way, course that represents a vertical distance
we can use contour lines to work out how much
slope there is on our block of land and closer the lines are together
the steeper the block of land is going to be
And I'll show you that with this next
picture, so here's the heap of contour lines these ones
happen to form a circle
And you can see the ones on this side of the block of land are lot closer together than the ones on this side
So generally where you see a circle
that's going to represent a hill or a rise in the land, so here you contour lines in
the 3D Model
It's still
500mm apart
But because there it's steeper on this side
they look closer together and as it's not so sleep on this side, then they're further apart
So the big thing to remember is a contour line
represents height
It's got nothing to do with the vertical
Or the distance apart for the line. It's all about the height of the line
another thing that the set of contour lines in a circle could represent
Again is they could represent a depression
Or a hole in the ground
so there you go that's what contours are and what what they represent and how the contour interval works in
The next video I'll show you how you can use contour lines to work out
what slope your block of land is without even having to visit it.