Iowa Redistricting, 2010

[jimrtex]

The way they define "compactness" has the effect of favouring L-shaped districts. (see especially 1, 2 and 4 currently.) This may be less of an issue with only four districts.

Sort of.  The two arms of the L have have equal EW and NS extent (except you can do a hockey stick on the Nebraska border (the EW measurement is from the NW corner of the state to wherever the blade of the stick ends up along the Iowa border.

But you are able to nest L shapes inside each other.   Or sometimes you can have the inside of the two Ls facing each other and pick counties out of the middle.

In the current map, CD1 and CD2 get their compactness from the outer L-shape.  Including counties from the inside of the L, has no effect on their "compactness".

[jimrtex]

The state does non-partisan, judicial based re-districting, right?

They don't permit splitting counties, and districts are required to be compact (in Iowa, this means equal distance between EW and NS).  They also are required to ignore race, politics, and residence of incumbents and current districts.

The districts are actually prepared by a state agency and then approved by the legislature.  After the 2000 redistricting cycle, the legislature voted down the first plan, saying that the deviation was too large (I think one district was off by about 150, which is less than 3/100 of 1%).  I suspect that they just didn't like the districts.