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Style digital elevation models (DEMs) and other terrain layers to show beautiful context and information.
How to download topographic layers: https://youtu.be/JJFBEsNUCnw
Check out my website for more: https://opensourceoptions.com
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0:01
Welcome to Open Source Options. Great to
0:03
have you with me today. Uh in this
0:05
tutorial, I'm going to show you how we
0:07
can use QGIS
0:09
to style topographic data so it makes
0:13
our maps pop and give some additional
0:16
context to makes our maps useful. Now,
0:20
before we get started, just know that
0:22
coming out soon will be my GIS
0:24
foundation class. uh go take a look at
0:27
that or go to the website opensource
0:28
options.com to be notified when that
0:31
comes out. But now let's go ahead and
0:34
get started. You can see here I'm in
0:36
QGIS and I have some layers added here.
0:40
Uh you'll notice that we have just this
0:43
grayscale digital elevation model and
0:46
this is kind of your default symbology
0:48
and default styling that you'll see and
0:51
it works. Uh we just have our elevation
0:54
values
0:56
described here in meters and the low
0:58
values are black and the high values or
1:02
taller peaks and areas are white. But we
1:05
can make this more visually appealing
1:07
and add some context in a couple of
1:10
different ways. Now first let's go ahead
1:13
and change the color ramp that displays
1:18
this so that it's not black and white.
1:20
And I'll show you why. We'll explain why
1:22
we're going to do this in just a minute.
1:24
But to do that, we're going to come over
1:26
to our layer styling panel. You can
1:28
access that by going to view panels and
1:32
turning on layer styling here. Then you
1:35
can move it around and dock it wherever
1:37
you like. I put mine over on the right
1:40
side here. I'm going to change this to
1:42
single band pseudo color. And you'll
1:45
notice now it pulls up this ramp that
1:47
goes from blue to yellow. There are
1:50
other topographic color ramps available
1:54
and a lot of the default color ramps
1:58
aren't the best for elevation. We can
2:01
use something like turbo which works a
2:03
little better. It has a few more colors
2:05
and gives us uh some more definition.
2:08
But with QGIS,
2:11
if you go to create new color ramp
2:15
and you should have these available. the
2:18
CPT city and color brewer. I like some
2:22
of the ramps in CPT city. Okay, so this
2:25
catalog should be added in for you by
2:27
default. So go to catalog CPT city and
2:30
select okay. Now even though we selected
2:33
create new color ramp to get here, we're
2:35
not going to create a new color ramp.
2:38
You'll notice that this just pulled up
2:41
this dialogue here and there are many
2:43
different color ramps here. Let's go
2:46
ahead and click on topography.
2:48
And you can see we have a lot of
2:50
different options here that we could
2:52
use.
2:54
Uh we have some ezree styled ones. Um
2:58
the one I like is I'm going to choose
2:59
this elevation one here that kind of
3:01
goes from this blue to green to yellow
3:03
to orange to brown to black and say
3:05
okay. And there you can see that just by
3:08
doing that we get a little more
3:09
definition in the colors. Those high
3:12
areas pop out a little more as do the
3:14
low areas. Now, the real reason we
3:17
wanted to do this, or not the real
3:18
reason, but a main reason is so we can
3:21
add a hill shade and use that hill shade
3:23
to add some context and texture to our
3:27
map. So, if you're not sure what a hill
3:29
shade is, we'll create one so that you
3:31
can see it. And there are a couple of
3:32
different ways to do this. I'll show you
3:34
both of them. One is we can just create
3:37
a copy of this layer. So, let's uh
3:41
duplicate the layer here. Right click,
3:43
duplicate. I'm going to slide it up on
3:46
top
3:48
and I'm going to rename this to
3:49
hillshade
3:51
so that
3:53
uh we can keep things straight. Instead
3:56
of copy, I'm just going to call this
3:58
hlsd for hillshade.
4:02
And now when I turn this on and I come
4:05
over here to my symbology options for
4:09
this layer, make sure you have the
4:10
hillshade layer selected in table of
4:12
contents.
4:13
Instead of single band pseudo color, I
4:15
can select hill shade here. And now you
4:18
can see this hill shade. It gives us
4:19
kind of this surface uh textured surface
4:22
that shows what the topography looks
4:25
like. That adds some additional context
4:28
that we don't get with just that color
4:30
gradient. Now, we can adjust these
4:33
parameters here. Usually, you won't need
4:35
to, but we can see where the flat areas
4:38
are. We can see where the steep areas
4:39
are and the rough areas are.
4:42
And we can combine this
4:46
with our color,
4:48
our colored gradient by changing the
4:51
opacity. So I have the hillshade on top
4:54
of my color dem. I'm going to pull the
4:56
hillshade opacity down to about 40%.
5:05
Okay. And now you can see that we have
5:07
that color with that texture. And you
5:09
can play around with this opacity to see
5:11
where you like it. We can put it up
5:13
higher. We can pull it down lower.
5:15
Usually between 40 and 60% is your best
5:19
option depending on exactly what you're
5:21
trying to show. But you can see that
5:24
just by adding that heel shade in, we
5:27
have a whole lot more context and a
5:31
whole lot more definition in there. Now,
5:34
let me show you why we needed to we
5:38
couldn't use a a white to black color
5:41
ramp here. So, first it's because the
5:43
hill shade has that black to white color
5:45
ramp on it. But if we come here and
5:49
let's go back to our styling on our DEM,
5:51
which is this filled full. Um, let's go
5:55
back to single band gray. And now we do
5:59
this and we can't really tell. I mean,
6:01
we get some it's much harder to tell
6:03
those where those high areas are because
6:05
we have a transparent black and white
6:07
over black and white and it can kind of
6:09
confound the other one. So, generally
6:12
speaking, our dark values are in lower
6:14
elevation areas and our white values are
6:16
in higher elevation areas. We have white
6:19
values here and white values here and
6:21
it's hard to see which area is higher
6:23
than the other
6:25
which is why we go back to single band
6:28
pseudo color and I have to go back and
6:30
pull this color ramp in again but you'll
6:32
get to see it. So we create new color
6:34
ramp. We come down to catalog CPT city.
6:37
We click okay. It pulls this up. We go
6:40
to topography and we select elevation.
6:43
And there we have that. And that is how
6:46
we can create some striking topographic
6:51
visualizations that are cigraphically
6:54
correct uh and also uh cardographically
7:00
appealing.
7:03
That's all for today. Thanks for
7:05
watching. I hope you enjoyed this video.