Place a whole lot of pads
You can use Altium's Paste Array feature to do this. It would need to be done for each segment.

Start by placing a hole/pad/via at the starting point. Copy this pad, then delete it (it will come back in the next step).

Go to Edit -> Paste Special... (or E, A as a shortcut). The next dialog should have a list of Paste attributes. For this case, you can leave them all unchecked, then hit Paste Array ...

In this dialog, you have a few options. Under item count, select how many copies that you want, including the copy that you deleted. So if you want 10 holes, put 10 under Item Count. Text Increment is for pad numbers. An increment of 1 will make the numbers increase by one each time. If you don't care about this, then put 0. Under Array type, you want Linear. Then under Linear Array, enter the X spacing and/or Y spacing. Negative X values will place the copies to the left, and Negative Y values will place the copies down. If you enter both, the copies will be pasted at an angle.

Finally, click OK and you will be given a crosshair as if you were pasting one part. Click where you want the array to start and the whole array will be pasted.

Altium has more information on these menus:
http://techdoc.altium.com/display/ADRR/PCB_Dlg-PasteSpecial((Paste+Special))_AD
http://techdoc.altium.com/display/ADRR/PCB_Dlg-SetupPasteArray((Setup+Paste+Array))_AD