Michigan: The urban-rural divide writ large

[muon2]

Chops themselves are subjective and aren't used by many mapping regulations in the country.   Communities of interests and avoiding partisan interests (like vote sink districts in your MI-9) are a better alternative.   County/City lines are very often outdated and serve very little real purpose.

I strongly disagree. Many states that do have mapping regulations do pay attention to chops and the need to minimize them. Recent redistricting reforms in FL and OH very much care about keeping counties and cities intact. The overthrow of the VA and FL plans rested in part on the court's concern that there were too many chops into counties to create the minority district. Public testimony in states without such regulations in 2011 included a great deal of comment about preserving counties and cities. For most people outside of the largest cities the county and city make up their main basis of identifying their community of interest.

[muon2]

In the current edition of muon rules, as long as there is a local road connection beyond the nick path, then the plan is permitted. There is just a point of erosity penalty for having two separate components. That's how the nick path problem is resolved.

[muon2]

I looked at my map, and your point is moot here. MI-179 runs from Bradley to Hastings so the Allegan fragment in the pretty map is regionally connected to Barry. Pretty wins.

[muon2]

I looked at my map, and your point is moot here. MI-179 runs from Bradley to Hastings so the Allegan fragment in the pretty map is regionally connected to Barry. Pretty wins.

You don't consider that there is a state highway connection to Kent County?  It needs to be the same highway number to count? Putting that aside, weird road connections can lead to weird maps.

Kent county is in a different CD, so any connections will result in the same score with either plan.

Connections do not need to be on the same numbered highway all the way from county seat to county seat. There must be a continuous path of numbered state or federal highways to form a connection.

Presumably weird road connections may indicate unusual traffic patterns between counties. The point of the regional connection is to identify significant connections from other local roads.

edit: In this specific case the border between Allegan and Barry includes the Yankee Springs State Recreation Area. One might expect a lot less traffic through that area accordingly, and MI-179 was only dedicated in 1998. A large forested park with lakes is a bit like a mountain range for MI, and if MI-179 wasn't there it should be treated that way.

[muon2]

No, unless I misunderstand something, in the pretty map, the state highway from the county seat of Allegan where it joins US 131 near Plainwell slips into MI-06 as one goes north on Hwy 131 for a bit before going back in MI-02 on its way to Kent County, while staying in Allegan County the whole way until it hits the Kent County line. Sure it is a circuitous route, that probably nobody would use that wants to go from Allegan to Grand Rapids, but rules are rules. So that is an extra highway cut no? In the ugly map, there is no wandering into MI-06.

Allegan is not a macrochop so all that matters is which district the road enters in the chopped county. Roads between towns within a county only come into play in a macrochop. In general, the number of links between counties doesn't change when a simple chop is made, all that changes is where those links between counties are assigned. Here a link to the relevant example.

[muon2]

No, unless I misunderstand something, in the pretty map, the state highway from the county seat of Allegan where it joins US 131 near Plainwell slips into MI-06 as one goes north on Hwy 131 for a bit before going back in MI-02 on its way to Kent County, while staying in Allegan County the whole way until it hits the Kent County line. Sure it is a circuitous route, that probably nobody would use that wants to go from Allegan to Grand Rapids, but rules are rules. So that is an extra highway cut no? In the ugly map, there is no wandering into MI-06.

Allegan is not a macrochop so all that matters is which district the road enters in the chopped county. Roads between towns within a county only come into play in a macrochop. In general, the number of links between counties doesn't change when a simple chop is made, all that changes is where those links between counties are assigned. Here a link to the relevant example.

So you don't need a state or federal highway that covers the entire distance within the chopped county? Once a state highway enters the chopped county, it no longer matters if you have to use a county highway within the CD to get to the county seat (because the available state or federal highways wander outside the CD)?  If so, that might allow for some pretty nasty chops into a county, as long as no macro chop is involved. Just be careful to avoid a chop on the county line that cuts off the state highway entry point.

We had a lengthy discussion of the pros and cons of this looking at towns in Stark county OH and school districts in King WA. One of the better examples of a simple chop county we analyzed was this one.

I think the confusion goes back to the fact that the connection is defined by a whole path, not a road on the border. A connecting path may or may not be cut by a district boundary. If a district boundary cuts a connecting path then it adds to erosity. For nodes in different counties that path is made of state highways such that no other geographic unit is intercepted by the path. For counting erosity the county line only matters if it's the same as a district boundary.

Let's make sure we are on the same page with AL before we go to OH.


nb. The highways I describe aren't marked on the map. AL-17 is the road north from Chatom through Millry, AL-56 goes east from Chatom to Wagarville, and US-43 goes between Wagarville and Leroy (it's marked in Clarke county).

In chopped Washington AL there are two subnodes. One for the blue district in Washington at the county offices in Chatom. One is for the green district centered in Leroy. For Chatom the node is on AL-56 just west of AL-17. For Leroy the node is on US 43 (using either the high school or post office since it doesn't have an incorporated city government). So far so good?

To test for connections to Choctaw I must find a path of numbers state of US highways that goes from each of those nodes to Butler, the county seat of Choctaw. Without the chop there is a path from Chatom to Butler that goes north on AL-17 after a short piece of AL-56 in Chatom. It says in the two units (whole county Washington and Choctaw) so it's a connection. If it gets cut by a district boundary it adds to erosity. Does this work as an description of how I test for a connection?

In the chopped county I can use the same path from the blue subunit with its node at Chatom. In the chopped county that path goes through the green subunit, so it fails to stay in the two units I seek to connect (the blue Washington subunit and Choctaw). This is probably the first puzzling part.

The path from Leroy to Butler goes SW on US-43, west on AL-56 and north on AL-17. In the chopped county that path goes through the blue subunit, so it fails to connect the units I seek to connect (the green Washington subunit and Choctaw). If the preceding paragraph was puzzling, this may also be.

Recall that we have established that a connection exists between the two counties when they are whole. Yet when the chop is in place I can't draw a connection between either node and Choctaw without going through the other subunit. That leaves me with the four choices I outlined earlier:

A. Remove the connection since the path goes through both subunits on its way to Choctaw from either subunit node. It would not count towards erosity then.

B. Establish the connection to the blue subunit since the path goes more directly through its node and it is otherwise locally connected farther west along the county line. It would count towards erosity since it is cut at the county line between two districts.

C. Establish the connection to the green subunit since the path crosses from that subunit at the county line. It would not count towards erosity since Choctaw is also in the green district so it isn't cut.

D. Create two connections to replace the original connection, since without a regional connection both subunits can claim local connections to Choctaw. One of the two connections would now be cut and count towards erosity.

Since there was a connection that could contribute to erosity without the chop, I don't like the idea that no connection to Choctaw remains after a chop. That invites chop games to eliminate connections (I think jimrtex observed this a few years ago when I started defining erosity). It's enough that the chops can be strategic to reduce erosity without eliminating connections. So I don't like option A.

Option D creates more links than initially exist to other counties. We've restricted that to macrochops so that simple chops are not overly punished in the erosity score.

That leaves two options, and of those option C has been the preferred interpretation for cases like this. If you're still with me and think I've missed a reason to go a different way in interpretation, please weigh in.

[muon2]

So is my statement true?  Some of the confusion I think arises from the other discussion about what counties are connected for purposes of being allowed in the same CD (where this issue I know came up). But here, we are just chatting about whether or not an erosity penalty point is in play.

The statement that careful selection of where a district cuts into a county can be used to lower an erosity score is true. There are consequences to any of the possible interpretations of a county chop like we are discussing. I thought that on the balance we generally agreed that the consequences were worse with other interpretations.

On the question of which counties are regionally connected I posted this map two years ago during our analysis of different MI plans looking for the Pareto frontier. The only change since then is that local connections can be used to connect counties, but with an erosity penalty.

[muon2]

With reference to the pretty map versus the ugly map, they are tied for chops and erosity. So then one turns to partisan aspects, but that is tied too. And then there is equality. If the ugly map is more equal, that wins, but the maps are tied there too (the 5th and the 8th CD's define the extremes).  So do you flip a coin?  Was it finally resolved how equality plays into the formula for picking maps, or is that still up in the air?  I recall Muon2 wanted to give it more importance, and I was resisting. I think partisan balance is more important.

I assume that this is hypothetical since I showed the pretty map has a lower erosity due to the existence of MI-179. When we (Torie, jimrtex, traininthedistance, muon2) drew multiple MI maps with 2010 data we looked at the role inequality could play. We scored maps in different ways, including use of populaton as a tie breaker. Our conclusion was that the best use was to add the INEQUALITY score to the CHOP score as one axis of the Pareto test. This the table used to determine the score.

The INEQUALITY score for a plan is found by taking the range for a plan and comparing it to the table below.

Range	Inequality
0-1	0
2-10	1
11-100	2
101-400	3
401-900	4
901-1600	5
1601-2400	6
2401-3200	7
3201-4000	8
4001-4800	9
4801-5600	10
5601-6300	11
6301-7000	12
7001-7700	13

This creates some incentive for lower inequality, but any lowering must be substantial enough to offset any extra chops.

[muon2]

Point taken, but there has been a clear shift in small towns in the upper Midwest over the last few cycles. If the economies of the rural counties once saw themselves integrated with the industry of the major metro area, they don't anymore. That may define the politics of the next map.

[muon2]

The full post that's quoted shows the data used to derive the INEQUALITY table. (You've asked this question before and it's now part of the stickied Muon Rules thread). It was tested extensively in the MI threads from a couple of years ago that I referred to.

The theory is that if equality is the goal each chop should serve to reduce the range. The table translates the expected reduction in range for a given number of chops, so that if INEQUALITY is added to CHOP the total should remain constant for those seeking to get greater equality - ie a Pareto equivalence. A better map gets more range reduction with fewer chops.