I'll tell you - I'm glad you've started this topic because I've refined my positions just yesterday...

i say refine because my finger placement interval has gotten shorter ... Shorter gaps between notes. You should also consider tones; attention to pitch - because you will begin to hear sounds that aren't the note your looking for, especially in higher positions. Recognizing these things are often : what advancing in violin is about (refinement).

for example last week I was playing a D and this week I've realized that D is actually more of an E/F. Thus my finger grouping has shuffled closer to the scroll across the entire fingerboard in order to refine the tones and resolve those inaccurate fluctuations between string crossings. 

I tell you these things to shed light on potential encumbrances that you may be dealing with.

as for figuring the correct pitch for yourself you can play a double stopped octave (first finger on the lower string with your fourth finger on the higher string) but even still with that technique, it may prove difficult to imitate the actually octave without great ears. I think that when it comes down to it, and you're practicing scales; you WILL hear the inconsistencies so you CAN fix them there - on the fly.