New Zealand Rail Maps Mapping New Zealand's rail lines
Creating and Editing Paths in Google Earth
Creating
and Editing Paths
In all of the maps in
the NZ Rail Maps site, I use paths to show routes. The path is a
sequence of individual points. I can place the points on the map at any
place, and Google Earth automatically draws the path between successive
points.
Therefore the creation of a path simply involves adding the points in
the right places. You can edit a path by dragging points to new places,
adding additional points, or deleting points. The line that Google
Earth draws between the points can have its colour, width and opacity
changed.
Create
a Path
Click on a folder that you want to create a path in
Click on the Add menu and then click Path. This will open a box
like the one below.
Give your new
path a name, and if you wish, a description. Leave this box open for
the moment. Just drag it to somewhere on the screen where it won't get
in the way of the map.
Now you need to decide where to put the first point of your path. In
this tutorial, I refer to this first point as the "origin". The last point I refer to
as the "end". I'll explain
these terms a little bit more shortly. This just has some relevance to
where you should put the origin point. I usually put it, in railway
terms, at the lowest milepeg on the rail line I am working on, and work
in the direction that the mileage runs.
To start drawing, just move the crosshairs to where the origin should
go, and click. A green point should now be visible on the map. To
extend the path, just move to a new position and then click again. As
you add each new point, a line is automatically drawn between
successive points. A curve is just a lot of points that are close
together.
Below you can see a yellow line that I've created, with its points in
red (except for the active point, which is blue. I'll explain that more
shortly). Each time you add a new point, it is inserted after the
active point, and the new point you have added becomes the active point
(blue).
To finish
editing the path, click the OK button in the "New Path" box that opened
when you added the path. You should now see your new path with this
icon next to it, something like this (the caption will be whatever you
named it); .
Note the path icon; it is three points arranged in a triangle with
lines joining them.
Edit a Path
You can edit an existing path at any time. Examples of what kind of
changes you might want to do could be:
You can drag any point to a new place.
You can add new points to the end of the path (after the end
point)
You can add new points after an existing point (between the point
you selected and the next point
You can delete points
You can change the style of the line. (Not covered here but you
should be able to work it out easily enough)
Firstly you need
to open the path for editing:
Select the path
Click the File menu and click Properties
This will open a
box like the "New Path" one you saw above except it is now titled "Edit
Path". Otherwise it is exactly the same.
At the same time, the path will change on the map so that all of the
individual points can be seen.
Google Earth stores the points of your path in a definite order. The
origin is always the first point in a path. The end point is the last
point on the path (at the opposite end from the origin). (more of this
shortly)
Dragging points You can drag any
point in a path to a new location on the map. The line is automatically
redrawn.
Adding points to the end of the path You can add a new point after the end of the path at any time.
You need to first select the end point (it will change colour to blue)
and then click at the new location on the map.
New points can only be added to the end. You cannot extend the path at
its origin this way. (There is however another way of doing this which
I will describe shortly).
Adding new points between existing
points You can insert new points between existing points in the path.
In relation to the path's origin, you are inserting these points
"after" the active point. Select an existing point on the map (it will
change to blue). Then click on the map where you want your new point.
The path is automatically redrawn to include the new point.
Deleting points You can select any point on the path and delete it. When a point
is active (blue), press Delete on the keyboard to delete it (or click
the right mouse button). The path is automatically redrawn.
Extending the line at the origin or
changing the origin
The origin is always
the first point of any line. Because you can only insert new points
after an existing point, Google Earth doesn't let you add a point
before the origin to make a new origin.
However, you can drag the origin to a new place on the map, and then
"fill in" the path between the origin and the next point on the line,
by adding new points after the origin.
The only way of changing the origin is that by deleting it, the next
point in the line will become the origin.
Close the Edit Path box by clicking OK when you have finished editing
the path.
If you have got this far and are getting the hang of creating and
editing paths, then you are doing really well. Click here
to go back to the Tutorials menu on the website to see if there are any
more Google Earth tutorials for you to try.
.
