Help – Matrix applications and civil engineering

I have a problem. One of my readers asked me a question and I don’t have an answer. The question (paraphrased and mangled slightly) is:

How do you picture matrix least-squares method of a traverse adjustment in surveying and in strain-stress material? Tell me about diagonal matrix practical interpretation.

I think my brain exploded after reading it. What in tarnation is a traverse adjustment? Holy smokes, strain-stress material? I have no idea what I was in for…

After weeks of sitting on it, and doing some preliminary research, I’ve decided I can’t answer it. I’m sorry I let you down, O reader who sent me the question. I presume this is related to civil engineering. I know little about it, and I’ll probably spout rubbish if I start answering.

This is where you come in. Help answer the question. You can write it in a comment, or contact me via email. A civil engineering reader gets help, and you get a warm fuzzy feeling of doing something good.

UPDATE: We have an answer.