I've looked at various sites and dictionaries, and 图号 seems to be mostly translated as 'chart number':
http://tech.zidian8.com/chemical/20110311025721_55597.shtml
In some instances drawing number is also used; however, I think 'chart number' is the right term.

地号 can be translated as 'parcel number':
http://www.showxiu.com/fan_yi/地号/


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Note added at 12 hrs (2012-06-14 11:19:04 GMT)
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You can also use the abbreviated forms of:
图号chart no.
地号parcel no.