I happened upon a handy App for designers that need to take field measurements. The App is called My Measures PRO by SIS software and is available from the Apple App Store and works on the iPhone and the iPad. The app is also available as an Android App. The SIS software website has a video showing how the app works http://www.sis.si/my-measures/ .
The app takes or uses photos you have taken to record the dimensions of what is shown in the photo. You will still need to measure, but you can record the measurements right on the photo. This gives you a better record than a sketch on which you add dimensions because of all the other information that is documented in the photograph - like electric outlets, thermostats, etc. You would probably want to photograph the spaces you are measuring anyway , but without this app, which is very easy to use, you would tend to store the dimensions elsewhere. Now you can have them in one file, and it is also worthy of sharing with others (my field notes are rarely of any use to anyone else - even with an explanation of what I was trying to document).
This video gives you a two minute introduction to how My Measures works.
There are two versions of the app - basic and PRO. Basic version is $3. Occasionally this version will be free. I use AppsGoneFree, an Apple App Store app, that can send you an alert every day about apps that are temporarily free, which is how I 'discovered' My Measures. The PRO version, which I upgraded to for $1, has a few features that seem worth having - iCloud synch and backup, zoom the picture, snap for arrow heads, loupe mode, which shows an enlargement for accurate arrowhead placement.
One problem that this app solves for me is thoroughness. I rarely end up with photos of everything I need despite my intent to photograph the crap out of the space. This app makes you think about photographing what you want to measure, so you are thinking about whether everything is showing up in the photo. This slows the process down a bit, but if it saves (as it does for me) the inevitable return visit, you are saving time.
For those spaces that are difficult to get good photos of there is another app, Photosynth by Microsoft of all people, that takes very nice stitched-together photos. These import into My Measures just like any other photo.