In the Processing Toolbox use the Extract Specific Vertices tool, for the Vertex indices use 0 for the first vertex and -1 for the last vertex. Which one you need will depend on the direction of the line.
EDIT: Apologies, I didn't read your question properly, you said automatically. If it's just for display purposed you could use a geometry generator ...
Tested on QGIS 2.18 and QGIS 3.4
I can suggest using a "Virtual Layer" through Layer > Add Layer > Add/Edit Virtual Layer...
Let's assume there is a polyline layer called "polylines" (blue lines).
With the following Query, it is possible to create a point at the end of each line.
SELECT st_endpoint(geometry), *
The output point ...
If you want to write all the values of the ycoord field into a .txt file, you can execute the following code in the Python Console of QGIS (change the parameters with your own):
layer = iface.activeLayer() # your layer
features = layer.getFeatures() # features of your layer
with open('C:/Users/v.bre/Downloads/ycoord.txt','w') as my_file: # Change the path ...
Select all the features you want to have a different color.
Use the Field Calculator to add a new field. Check the box for "selected features only". Fill in a field name, and fill in a value in the expression area (in my example below, I called the field "category" and filled it with the value 1.
Now the point layer has a new field called "category". The ...
Já tentou usar o complemento Networks? Você pode instala-lo pelo menu complementos, depois de instalado ele fica no menu processar/caixa de ferramentas.
A página do complemento é: https://github.com/crocovert/networks/
Have you tried using the Networks add-on? You can install it from the add-ons menu, once installed it is in the render ...