In this demo, you'll learn how to create a custom projection
for a body that is not Earth.
Here we have the Moon. This is the Lunar Reconnaissance Orbiter
Wide Angle Camera mosaic. And first we'll need to check and
see what this current projection is. So we can right click on the
map title here and go to properties.
And if we go to the coordinate system section, this is the
current projection, here the SimpleCylindrical_MOON.
Let's say we want to look at this from the South Pole.
And we want to do, let's say, a South Pole Orthographic.
You can search for orthographic here.
And then if we expand down the projected coordinate systems,
there's a polar section.
And then there's North Pole and South Pole Orthographic. So we
can click on this, but that doesn't put us where we want to
be yet because if we go up here and check the details -
this is actually on Earth. This WGS 1984 is an Earth geographic
coordinate system, and we need to make this of the Moon.
So instead what we can do is we can take this South Pole
Orthographic as a starting point, right click it and do
Copy and Modify.
Now that we've opened the Copy and Modify
we can create a new custom projection here. First you want
to make sure you rename it.
And in here you can set any other things that you want to
do. You can center it on a different longitude. We'll keep
it on 0.
And then the important part is down here, the geographic
coordinate system. This is what will change. So right now it's
set as Earth.
But we're going to change it to the Moon.
Now that we've set the geographic coordinate system to
the moon,
If you scroll through and just check anything else that we want
to just make sure is correct, we've renamed it so we know that
it's the Moon.
Click save.
And you'll see it listed down here in your custom projections.
It's important to note that if you don't do anything else right
now and you just click OK, this is going to disappear. That's
why there's an alert here.
So if you're not using it as the current coordinate system
and you don't save it to your favorites, it's going to
disappear.
So once you have one that you like, you can click this little
button here to Add to Favorites.
And when you do that, you'll see that it gets added up to the
list up top.
So now that I've clicked on that button, when I expand it I'll
see and I have a lot of custom projections already -
but this is where it is right here.
And now it's always there. It's never going to disappear. It's
always there from project to project and you never have to
recreate it.
We have it selected.
Click OK.
And there's our south polar view of the Moon.
We can change it to a different projection. So if we go back to
that coordinate system section
you could change it back to simple cylindrical.
So let's say we want to make an equirectangular view that's
centered at longitude 0.
We're can go find can find the generic Earth-based plate
carree.
Right click on that, copy and modify.
And we've got the central meridian is 0.
But remember this is an Earth-based projection, so we
need to change it back to the Moon.
Just give it a check over.
OK.
Now we've got it listed in our custom projections, we want to
make sure we click that star to add it to the favorites.
And then you'll see it listed there.
Now we have our plate carree projection.
Now this is centered at -
Let's change these to decimal degrees.
This is centered at 00. You can always check right here to see
what your center longitude is down at the bottom.
Let's say I want to switch it to be centered on 180.
Go back to that, you can also double click on the map title.
Now I already have this projection made, so this is a
quick and easy thing to tweak. We'll right click it, copy and
modify.
And we're going to change this to clon180.
It's already on the Moon because I used the custom projection
that I already have. So all I need to do here is rename it and
change that Central Meridian to 180.
Click save.
Click that star to add it to my custom projections.
And then I'll select it up here and watch the base map.
Now my map is centered at 180.
And now you'll see these are always present.
In your favorites list up top here.
They're always going to be there, so you can very easily
now switch back and forth between your center longitude 0
and your center longitude 180.
And that's working with custom projections for bodies that
aren't Earth.