Line Modification
Tips for creating a line – like dropping points, freehand drawing and undo – were previously covered in this blog post. Options for modifying existing lines have slowly been growing, and I think it’s time to take a detailed look at them.
All of these options are accessed by right clicking on an existing line. Vertex dragging is also enabled when clicking the edit icon in the left bar.
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| the right click context menu |
The first option I want to cover is “Clone As”. This allows you turn a line into a polygon, add a styled line that matches a polygon border, or simply backup an existing line before editing or resampling:
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| right click -> Clone As -> Line. Done. |
Vertex dragging has been around for a while but it’s worth a quick look. Right click – > Modify -> Drag Vertices.
At this point each vertex along the line or polygon gets a draggable white circle. Midpoints between vertices also get a partially transparent circle, which you can drag to create a new vertex. To delete a point, right click on it and choose Delete Vertex.
When you’re done modifying the line, right click on it and chose Save Changes – or, if you made a mistake, Discard Changes.
Sometimes it’s useful to break a line in two – say to delete a bunch of points at once, or to get around a GPS’ limitation on the number of points per route. To do this, simply right click on a line at the point where you want it split, and choose Modify -> Split Here.
The opposite of splitting is joining. To join lines, one of the two must have a label. Right click on the unlabeled line and choose Modify -> Join Lines.
A dialog will come up asking what line you want to join with. If the two lines don’t touch, CalTopo will automatically pick the best way to connect them.
Drawing a freehand line creates a lot of points. This can exceed the limits of your GPS, resulting in only getting part of a route. It also creates jitter, since no one has perfectly steady hands. You can work around these problems by resampling a line, reducing the total number of points.
You can shrink a line down to a fixed number of points, or to create points at a fixed interval like 500 feet. You can also optionally add a marker at each resampled point, in order to load them as waypoints onto a GPS.
Finally, you can reverse the order of a line so that directional styles will point in the opposite direction.
can you merge two lines at a specific point, all while keeping the two different named lines separate?
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I'm sorry, but I'm having trouble trying to figure out what you're asking.
FWIW, for any modification, you can leave the original intact by right clicking, choosing Convert -> Copy as (line/polygon/etc) to duplicate the line, and then modifying one of the two copies.
Is there a bulk delete for vertex’s? Other than splitting and joining?
No there is not.
I am using a MacBook pro with ventura and am unable to delete vertices. I’ve tried it using both safari and chrome browsers. Right clicking does not bring up any options.
Sorry to hear you’re having trouble. Send us an email at help@caltopo.com with a description of the issue and we’d be happy to help you troubleshoot.
After you join two lines, how do you control where the start of the line is? I have a loop I created, but the start is stuck in the middle of nowhere, and I am trying to relocated it to a trailhead. I’ve tried splitting the loop, joining part 1 to 2, joining part 2 to 1, splitting and then reversing part 1 then joining… etc.
When you use the join function, the program looks to connect the closest point on each line you are joining. This is typically not an issue when you joining lines on a one-way route; however if you are joining lines on an out and back (such as in a lollipop route), it can get tricky. Send us an email at help@caltopo.com with a link to your map and description of the issue and what you are trying to accomplish. We would be happy to help you troubleshoot!