Using Urban County Clusters To Guide Redistricting

[Sol]

I think, aside from the VRA issues, the biggest issue with this approach is this dilemma- Is it preferable to have a a district that swings in a circle around an urban center to maintain UCCs, or to split the cluster into neighboring rural districts to minimize erosity? A good number of these counties might be more tied to neighboring rural places, after all.

The whole point of this UCC business, as I see it, is to try and come up with an alternative, more stringent definition of "metropolitan area" such that the outlying rural and rural-ish counties in a metro area are free to go in a rural district, whereas the urban centers and well-developed suburbs remain tied together.  Basically, if we're defining our terms right, the counties in the UCC won't be more tied to neighboring rural places- they'll be most tied to the metro center, or at least some associated satellite/edge city.

I understand. The specific example I had in mind was Charlotte, where you basically have to create 2 districts- A Charlotte based one and a greater suburban one, the latter combining some areas that are quite far apart*. The new district is also quite erose. This is the point where many would question whether putting Gaston county with Union county is any better than splitting the Charlotte UCC.

*I believe the Charlotte UCC is actually greater than 2 districts in population, but I don't believe that's relevant (correct me if I'm wrong! )

I personally have zero problems with a Gaston-Union district (which would also include a couple hundred thousand folks from Mecklenburg), though of course that is a case where the algorithms might blanch at using Mecklenburg as a bridge.  There is, in my mind, a pretty compelling case that "outer suburbs of Charlotte" is a quite cohesive community of interest.

Oh, I agree with you-outer Charlotte is a COI. But some people would not agree, and many people would dislike that erosity, particularly those in Gaston/Lincoln county, which has similar characteristics to the adjacent areas to the North and West.

I was using Charlotte as an example of how UCCs can increase erosity and occasionally force the combination of areas which may not go together as a COI (I'm sure there's a better example of the latter phenomenon than Charlotte- I have to think).

[traininthedistance]

I think, aside from the VRA issues, the biggest issue with this approach is this dilemma- Is it preferable to have a a district that swings in a circle around an urban center to maintain UCCs, or to split the cluster into neighboring rural districts to minimize erosity? A good number of these counties might be more tied to neighboring rural places, after all.

The whole point of this UCC business, as I see it, is to try and come up with an alternative, more stringent definition of "metropolitan area" such that the outlying rural and rural-ish counties in a metro area are free to go in a rural district, whereas the urban centers and well-developed suburbs remain tied together.  Basically, if we're defining our terms right, the counties in the UCC won't be more tied to neighboring rural places- they'll be most tied to the metro center, or at least some associated satellite/edge city.

I understand. The specific example I had in mind was Charlotte, where you basically have to create 2 districts- A Charlotte based one and a greater suburban one, the latter combining some areas that are quite far apart*. The new district is also quite erose. This is the point where many would question whether putting Gaston county with Union county is any better than splitting the Charlotte UCC.

*I believe the Charlotte UCC is actually greater than 2 districts in population, but I don't believe that's relevant (correct me if I'm wrong! )

The Charlotte UCC is about 2 1/2 CDs so it has to add some population. Mecklenburg has to be chopped, and there's no rule that favors keeping one CD entirely within as opposed to splitting Mecklenburg relatively equally between 2 CDs. The chop count would be one either way, so if you can make a plan less erose that would be preferred.

I wonder if perhaps there should be such a rule, actually.

[Torie]

What is the HVAP issue? I can't readily find a post above about that. If this is a HCVAP matter, that is circuit specific under the VRA if I recall correctly.

The issue is to extend the idea of the minority county clusters to Hispanic populations. Because of citizenship the 40%/50% categories don't really work and HCVAP is not available. For the purposes of clustering I suggested that 40%/50% BVAP be replaced by 50%/60% HVAP for clustering. That would be a reasonable proxy for HCVAP or whatever circuit-based value is needed to test for the ability to elect a candidate of choice.

Yes, that makes sense.

On another issue, I know you get penalized or banned (we argue about that), which respect to an excess chop into an urban cluster, but how about one out?  Can a chop in be made larger, thereby forcing a chop out from an urban cluster?  I asked because I can get microchops with the map below, with what presumably is a cut out to the north from the Birmingham urban cluster, rather than taking a bite of the county to the south (assuming the county to the north is not in the cluster, and the county to the south is).

One way to measure UCC chops is to count the number of districts that cover the UCC. In your case you have two for Birmingham and that's the minimum number. If you count by regions then the outward chop means that three CDs span the region, since it pulls in the chopped CD 7, which is one more than needed. Then again if we are still on jimrtex's first map from yesterday Walker is in the UCC so there are three CDs covering the cluster which is one more than needed.

Walker County being added because it is more than 50% urban? What is the rule change here? I thought the change contracted clusters, not expanded them. I am not sure I like the expansion. Color me confused as usual.

"If you count by regions then the outward chop means that three CDs span the region, since it pulls in the chopped CD 7, which is one more than needed." 

The "region" being what, which came from where, to be avoided by how?

[muon2]

Walker County being added because it is more than 50% urban? What is the rule change here? I thought the change contracted clusters, not expanded them. I am not sure I like the expansion. Color me confused as usual.

Me too. I posted two maps from jimrtex the other day. I'm waiting to find out what the change is. Walker was in at 3 pm sep 2 (and had been since the outset) and out at 9 pm.

[jimrtex]

Walker County being added because it is more than 50% urban? What is the rule change here? I thought the change contracted clusters, not expanded them. I am not sure I like the expansion. Color me confused as usual.

"If you count by regions then the outward chop means that three CDs span the region, since it pulls in the chopped CD 7, which is one more than needed." 

The "region" being what, which came from where, to be avoided by how?

Walker County being added because it is more than 50% urban? What is the rule change here? I thought the change contracted clusters, not expanded them. I am not sure I like the expansion. Color me confused as usual.

"If you count by regions then the outward chop means that three CDs span the region, since it pulls in the chopped CD 7, which is one more than needed." 

The "region" being what, which came from where, to be avoided by how?

NO! NO! NO! NO!

The first map from yesterday was simply an update of the MAP previously posted.  I had found some errors while creating the next version.   Walker is part of the Birmingham-Hoover Metropolitan Statistical Area.  Its largest urban core is Jasper Urban Cluster.  Since it did have a core urban area, it was colored red along with St.Clair (Pell City Urban Cluster) and Jefferson and Shelby, both of which have significant portions of the Birmingham Urbanized Area. 

Colored in pink were Blount, Chilton, and Bibb counties, which are also part of the Birmingham-Hoover MSA, but do not have an urban core.  Oneonta, Clanton, and Brent urban clusters have about 5 to 6000 persons each, and as you know the Census Bureau sets the threshold at 10,000 for a (potential) core of a Core Based Statistical area.

The second map did show the latest definition (but had no effect on the Birmingham area).  Walker is in pink because it has no part of the Birmingham Urbanized Area.   St.Clair is in pink because the 9% of its population in urbanized areas is below the 25% threshold.

Jefferson and Shelby are in red, as 90% and 76% of their populations, respectively are in the urbanized area.

[jimrtex]

Walker County being added because it is more than 50% urban? What is the rule change here? I thought the change contracted clusters, not expanded them. I am not sure I like the expansion. Color me confused as usual.

Me too. I posted two maps from jimrtex the other day. I'm waiting to find out what the change is. Walker was in at 3 pm sep 2 (and had been since the outset) and out at 9 pm.

I edited the previous map, and linked to it in message

topic=177731.176;msg=3854508

which explained that it was a corrected map.

I then added the new map, and have been posting the updated definition and supporting data (so far I have done AL, AR, FL, GA, LA, MS, and NC.

topic=177731.181;msg=3854967
topic=177731.184;msg=3855099

[muon2]

Walker County being added because it is more than 50% urban? What is the rule change here? I thought the change contracted clusters, not expanded them. I am not sure I like the expansion. Color me confused as usual.

Me too. I posted two maps from jimrtex the other day. I'm waiting to find out what the change is. Walker was in at 3 pm sep 2 (and had been since the outset) and out at 9 pm.

I edited the previous map, and linked to it in message

topic=177731.176;msg=3854508

which explained that it was a corrected map.

I then added the new map, and have been posting the updated definition and supporting data (so far I have done AL, AR, FL, GA, LA, MS, and NC.

topic=177731.181;msg=3854967
topic=177731.184;msg=3855099

So was the first map was from the series where all urban areas counted at 50% and the second from the revised definition that only uses urbanized areas at 25%?

[jimrtex]

Walker County being added because it is more than 50% urban? What is the rule change here? I thought the change contracted clusters, not expanded them. I am not sure I like the expansion. Color me confused as usual.

Me too. I posted two maps from jimrtex the other day. I'm waiting to find out what the change is. Walker was in at 3 pm sep 2 (and had been since the outset) and out at 9 pm.

I edited the previous map, and linked to it in message

topic=177731.176;msg=3854508

which explained that it was a corrected map.

I then added the new map, and have been posting the updated definition and supporting data (so far I have done AL, AR, FL, GA, LA, MS, and NC.

topic=177731.181;msg=3854967
topic=177731.184;msg=3855099

So was the first map was from the series where all urban areas counted at 50% and the second from the revised definition that only uses urbanized areas at 25%?

No, the first map was from the series based on the whole metropolitan areas, with the counties without an urban core shown in a lighter tint.  Walker and St.Clair were potential micropolitan areas that became outlying counties.   St.Clair does have a bit of the Birmingham urbanized area, (9% of its total population), and could in the future become a central county of the MSA.  It would still not qualify as part of the UCC, unless it reaches the 25% threshold.  The first map also included the three "rural" counties in the MSA, Bibb, Blount, and Chilton (shown in pink).

The second map eliminates the three rural counties and classifies the 4 urban counties: Jefferson and Shelby as constituting the UCC, and excluding Walker and St.Clair because they had less than 25% of their population in urbanized areas.

[muon2]

Walker County being added because it is more than 50% urban? What is the rule change here? I thought the change contracted clusters, not expanded them. I am not sure I like the expansion. Color me confused as usual.

Me too. I posted two maps from jimrtex the other day. I'm waiting to find out what the change is. Walker was in at 3 pm sep 2 (and had been since the outset) and out at 9 pm.

I edited the previous map, and linked to it in message

topic=177731.176;msg=3854508

which explained that it was a corrected map.

I then added the new map, and have been posting the updated definition and supporting data (so far I have done AL, AR, FL, GA, LA, MS, and NC.

topic=177731.181;msg=3854967
topic=177731.184;msg=3855099

So was the first map was from the series where all urban areas counted at 50% and the second from the revised definition that only uses urbanized areas at 25%?

No, the first map was from the series based on the whole metropolitan areas, with the counties without an urban core shown in a lighter tint.  Walker and St.Clair were potential micropolitan areas that became outlying counties.   St.Clair does have a bit of the Birmingham urbanized area, (9% of its total population), and could in the future become a central county of the MSA.  It would still not qualify as part of the UCC, unless it reaches the 25% threshold.  The first map also included the three "rural" counties in the MSA, Bibb, Blount, and Chilton (shown in pink).

The second map eliminates the three rural counties and classifies the 4 urban counties: Jefferson and Shelby as constituting the UCC, and excluding Walker and St.Clair because they had less than 25% of their population in urbanized areas.

Thanks. Does the map change much if it goes to 40% in urbanized areas (still using 25 K as the alternative)? I ask since 40% seems to be the right threshold for counties to count in minority clusters. If urban clusters also used 40% it would establish that as a consistent benchmark to identify a county as part of a larger contiguous community of interest.

[muon2]

So using AL, here's where I think we are now.



The green counties are a minority county cluster defined as a contiguous group of counties with a BVAP of 40% or more.

The pink ovals are urban county clusters defined as a contiguous group of counties within a single metropolitan statistical area with an urbanized area of over 25K or more than 25% of the population in an urbanized area. (Consistency with minority clusters might suggest 20K and 40% as the two thresholds.)

The number indicates a cluster larger than a single CD and is the next largest number of CDs needed to cover the cluster.

Clusters represent communities of interest larger than a single county. A chop occurs every time a county is split, and a chop of a cluster beyond the minimum number counts the same as a chop of a county. The size of a chop is measured as the fraction of a district's population in the smaller fragment of a county created by a chop. Chops of counties or clusters less than 0.5% of the population of a district are microchops and do not count towards the number of chops.

Apportionment regions are a tool to minimize the number of chops and the size of chops. An apportionment region is a whole number of counties that is nearly the population of a whole number of districts. More regions is equivalent to fewer chops. To be consistent with counting and measuring cluster chops on the same basis as county chops, clusters should be placed entirely within one region.

[Torie]

I'm still confused about the matter of the size of the chop into an urban cluster, and the issue of my map going into Walker County, to accommodate microchops elsewhere. I think that flexibility should be there, but the point needs to be clarified. Good summary Muon2 of where I think we are, on matters where there is some consensus.

[muon2]

I'm still confused about the matter of the size of the chop into an urban cluster, and the issue of my map going into Walker County, to accommodate microchops elsewhere. I think that flexibility should be there, but the point needs to be clarified. Good summary Muon2 of where I think we are, on matters where there is some consensus.

Chopping out to facilitate microchops in other places is the essence of what regions do. In my view you have a Birmingham region with 2 CDs and a population deficit. The NW corner is a separate region with a population surplus that can shed some to your Birmingham region. The absolute deviations between regions is a measure of how many people get stuck in chops. I think a useful criterion is to minimize that quantity. However, at some point a chop gets large enough that it makes more sense to see the two parties to the chop as in a larger region.

[jimrtex]

Thanks. Does the map change much if it goes to 40% in urbanized areas (still using 25 K as the alternative)? I ask since 40% seems to be the right threshold for counties to count in minority clusters. If urban clusters also used 40% it would establish that as a consistent benchmark to identify a county as part of a larger contiguous community of interest.

The text accompanying the map indicates in green the edge cases (those with urbanized areas with between 25% and 50% of the county population.  Of the 15 edge cases (southeastern states of AL, AR, FL, GA, LA, MS, NC) 9 would fail a 40% threshold.  That is 60% of the 15, which matches (40%-25%)/(50%-25%), which indicates a somewhat linear distribution in that portion (overall, I believe that this represents a saddle).

Edge cases:

Montgomery, AL/Elmore County 27K/34%.   I-65 clips the southeastern corner of Elmore before entering Autauga County.   It appears that the Coosa flood plain is not develop-able, so that Montgomery can't directly spill into the northern counties.

Little Rock, AR/Lonoke County 31K/45%.   US-67 clips the northwestern corner of the county (around Cabot) which is the urbanized area, rather than east along I-40.  US-67 appears to be the traditional direct route to St.Louis (it is not as straight in Missouri, so that I-40 and I-55 via Memphis is just as quick though longer).

Fort Smith, AR-OK/Crawford County 30K/48%.  I suspect that there are enough retirees in the county that holds down the population in the urbanized area a bit.

Atlanta, GA/Walton County 28K/33%.  Walton is east of Gwinnet, and almost to Athens.  Monroe Urban Cluster is still separate from the Atlanta Urbanized Area.  The county doesn't have the best direct highway access to Atlanta proper.

Savannah, GA/Bryan County 9K/31%.  A large chunk of the middle of the county is part of Fort Stewart and non-developable.   The western end is a bit too far for direct connection to Savannah.  Though small, Bryan County has tripled in population in the last 30 years.

Athens, GA/Oconee County 16K/49.7%.  You can see the effect of relatively small county sizes in Georgia, so that even modest cities can have urban growth flopping into the next county.  With larger counties, the urbanized area can be contained within a main county.

Chattanooga, TN-GA/Walker County 31K/45%.  The Lafayette Urban Cluster adds enough population outside the urbanized area to keep it below 50%.

Dalton, GA/Murray County 12K/30%.   Dalton Urbanized Area crosses to include Chatsworth in Murray County.

Baton Rouge, LA/Iberville Parish  11K/34%.  Iberville is the last cross-river parish/county before Hennepin, with the area to the west of West Baton Rouge added to the parish later on.   So Iberville is really south of Baton Rouge, though it gives the appearance of being to the west.   The urbanized area crosses into Iberville in the area east of the Mississippi, and there is another portion linked through West Baton Rouge.

Gulfport-Biloxi-Pascagoula, MS/Hancock County 17K/39.6%.  Hancock is the least populous of the 3 coastal counties, and more than 10 miles from Gulfport, with Biloxi, and Pascagoula even firther way.  The Gulfport Urbanized Area crosses into the county at Bay Saint Louis on US-90 along the coast.  Diamonhead Urban Cluster on I-10 and further inland is separate.

Hattiesburg, MS/Lamar County  28K/49.6%.  Hattiesburg is directly on the county line, with I-59 looping the city to the west on the Lamar County side.  If not for the notch out of the northeast corner of the county, Lamar County would be over 50%.

Raleigh, NC/Johnston County  37K/22%.  Smithfield and Archer Lodge-Clayton urban clusters hold down the urbanized area percentage.  Johnston qualifies under the 25K test rather than the 25% test, and is a central county of the Raleigh MSA.  I would be inclined to keep the 25K test, even if the 25% threshold were increased.

Asheville, NC/Haywood County  26K/45%.  The terrain concentrates the urbanized area west from Asheville.  Haywood County might not qualify as part of the metropolitan area based on commuting.

Rocky Mount, NC/Edgecombe County  17K/31%.  Rocky Mount is on the Nash-Edgecombe county line, and barely qualifies as an urbanized area based on the Nash County portion.  Tarboro Urban Cluster holds down the urbanized area population in Edgecombe County.

Myrtle Beach, SC-NC/Brunswick County 40K/37%.  Brunswick County would qualify under a 25K test.  Brunswick County is a central county of the Myrtle Beach MSA, rather than the Wilmington MSA by a narrow margin.   20279 vs. 19636.   Commuting to New Hanover, NC is 5 times as great as that to Horry, SC.  This illustrates the propensity of urban areas to string out along linear features, like highways, or in this case along the coastline

Of the 190 urban core counties in MSA in AL, AR, FL, GA, LA, MS, and NC, 153 qualify for UCC based on a 50%/50K threshold; 15 fall within 25K-50K/25%-50% region; and 22 fall below the 25% threshold.  78 non-counties were excluded in the first pass.

So of 268 metropolitan counties, 153 (57%) are clearly in, 100 (37%) are clearly out, and 15 (6%) are edge cases.

[jimrtex]

I'm still confused about the matter of the size of the chop into an urban cluster, and the issue of my map going into Walker County, to accommodate microchops elsewhere. I think that flexibility should be there, but the point needs to be clarified. Good summary Muon2 of where I think we are, on matters where there is some consensus.

Walker has nothing to do with the Birmingham UCC.  So don't let that confuse you.

Since most of the population of Walker is in the northwest region, it is counted as part of the northwest region.  This gives a population of about 1.034 of the ideal.  While 3.4% is within a 5% range, it is a largish error, and might cause your plan to be excluded because other plans might have less error while using whole county regions.

The Birmingham UCC (Jefferson and Shelby) is in a 2-district region, or alternatively Jefferson is in a 1-district region, and Shelby is in an other 1-district region.

There is no problem going outside a UCC with your chops, since the regional rules should ensure compliance with the UCC for the most part.

Think of the regional map as an off-the rack suit, which you then have to fit.  You want to require the minimum amount of customization.

Do you have the population splits for Autauga, Washington, and Tuscaloosa counties?

[jimrtex]

This map presents the data for Alabama.  Population for each county is as a share of the ideal population of 682,819.  The Urban County Clusters are in pastel colors.

Whether an application presented only multi-county UCC and shows population as a number, is a quality of implementation issue.  The actual data set would have the actual population numbers, and the actual UCC delineations.

I did not treat racial information as being part of the rules, but available as data.  I chose to present that data using a 40% threshold (actually Jefferson, Russell, Monroe, and Montgomery are just barely below 40.0%, and I set the option for rounding before thresholding).  You can be quite sure I queried the BVAP for Pickens and Pike county before adding them to a region.

Borders (not shown).

Baldwin-Washington
Bibb-Jefferson
Cullman-Lawrence

Are considered to be near-corner contiguous and may not be used as a direct connection,  All 3 cases are classical (near) 4-point intersections.  Turn your head to see Bibb-Jefferson.

The following are considered to be contiguous:

Blount-Walker.   Border gap is slightly more than 10% of the square root of the are of the smaller county.  There is not good road connectivity, but both are part of the Bimingham MSA.  I could see local opinion as excluding this connection.

Chilton-Elmore.  Reasonable road connectivity plus large enough gap.

Dallas-Marengo.  Just misses the gap test (9.4%), but a direct road connection, and the Perry panhandle is more of an intrusion.  Someone in Selma would be puzzled if you suggested that Perry was to the west.   If they were giving you directions to Demopolis, they might mention that you would pass through a short stretch of Perry County.

Greene-Marengo.  Just misses the gap test (9.6%) but there is good road connectivity, with both lying along the east bank of the Tombigbee River.  Hale cuts into the connectivity a bit.  Hale is east of the Black Warrior River, which then forms the Green-Marengo border as it flows into the Tombigbee.

All such (non)connections would be established well before the process began, to avoid issues such as trying to decide whether Jefferson and Bibb are contiguous after noticing their populations.

[muon2]

The following are considered to be contiguous:

Blount-Walker.   Border gap is slightly more than 10% of the square root of the are of the smaller county.  There is not good road connectivity, but both are part of the Bimingham MSA.  I could see local opinion as excluding this connection.

Chilton-Elmore.  Reasonable road connectivity plus large enough gap.

Dallas-Marengo.  Just misses the gap test (9.4%), but a direct road connection, and the Perry panhandle is more of an intrusion.  Someone in Selma would be puzzled if you suggested that Perry was to the west.   If they were giving you directions to Demopolis, they might mention that you would pass through a short stretch of Perry County.

Greene-Marengo.  Just misses the gap test (9.6%) but there is good road connectivity, with both lying along the east bank of the Tombigbee River.  Hale cuts into the connectivity a bit.  Hale is east of the Black Warrior River, which then forms the Green-Marengo border as it flows into the Tombigbee.

All such (non)connections would be established well before the process began, to avoid issues such as trying to decide whether Jefferson and Bibb are contiguous after noticing their populations.

This list of amended connections is exactly why I do not favor the gap test model. In some mountain states there are stretches between counties that exceed the 10% rule but have no roads or some obscure local road at best. Road connectivity is a far better measure and can be used exclusively to get much the same result. Are there particular cases that you think should be in that would be excluded by road connectivity?

I do agree that there should be a local review and amendment process, but a baseline using road connections is a better starting point for that process.

[jimrtex]

The following are considered to be contiguous:

Blount-Walker.   Border gap is slightly more than 10% of the square root of the are of the smaller county.  There is not good road connectivity, but both are part of the Bimingham MSA.  I could see local opinion as excluding this connection.

Chilton-Elmore.  Reasonable road connectivity plus large enough gap.

Dallas-Marengo.  Just misses the gap test (9.4%), but a direct road connection, and the Perry panhandle is more of an intrusion.  Someone in Selma would be puzzled if you suggested that Perry was to the west.   If they were giving you directions to Demopolis, they might mention that you would pass through a short stretch of Perry County.

Greene-Marengo.  Just misses the gap test (9.6%) but there is good road connectivity, with both lying along the east bank of the Tombigbee River.  Hale cuts into the connectivity a bit.  Hale is east of the Black Warrior River, which then forms the Green-Marengo border as it flows into the Tombigbee.

All such (non)connections would be established well before the process began, to avoid issues such as trying to decide whether Jefferson and Bibb are contiguous after noticing their populations.

This list of amended connections is exactly why I do not favor the gap test model. In some mountain states there are stretches between counties that exceed the 10% rule but have no roads or some obscure local road at best. Road connectivity is a far better measure and can be used exclusively to get much the same result. Are there particular cases that you think should be in that would be excluded by road connectivity?

I do agree that there should be a local review and amendment process, but a baseline using road connections is a better starting point for that process.

We disagree about what road connectivity is.  You believe that a highway literally has to connect counties across the boundary.   I believe that there simply has to be a direct way to get between the two counties.  Before I-20 was built, you might argue that there way no way to get from Birmingham to Tuscaloosa, since US 11 cuts across a corner of Bibb County.

I might argue that there is an easy way to get from Cullman County to Lawrence County.

What I am primarily interested in is defining true adjacency.  We agree that point contiguity should not be used.  I think we agree that near-point contiguity should not be used.  But how near is near.  The gap test is reasonable since it works for townships, and little counties and big counties.  A district that connects Lawrence to Cullman is a cheat.

10% is somewhat aggressive, but it is a point where a more careful test should be considered.

An adjacency file would be absolutely necessary for an actual process.  It would be impossible to validate an actual plan without it.  Each record would require at minimum.

County_1, County_2.

We need the border length for measuring erosity, which is derivable from census data.  And we also need to define whether the counties are directly connectible.

Determining whether two counties are connectible is somewhat subjective, and thus can not be fully automated.   But we can provide partial automation:

If there is a gap of 10% or less than the square root of the area of the smaller county or there is only water connectivity, there should be a burden to establish connectivity.  If it is 10% or more, the burden should be to disestablish connectivity.  Emphasis should be placed on that this should not be used to disable pairings that people don't like.

So the final record would be:

County_1, County_2, border_length, connectible_TF

What I presented was what the local review process might have determined, or alternatively, if I were advising the local review, what my recommendations would be.  Any county pairings that I did not mention, were so obvious that they did not merit comment.

For Michigan and Louisiana, I did exclude some connections based on physical barriers.

[muon2]

But what we both also agree on is that there should be local amendments to any connectivity plan and they should be established well before the process. We differ on the starting point for those amendments.

I would start by saying any contiguous counties in a UCC should be considered connected even if the connecting road clips a county (for example Montgomery to Autauga). Many of the other county clipping connections would surely be added to the list by local choice. But since most of the local decisions are likely to be based on road connection, a baseline from connections is a better starting point. In your list road connections were a key factor, and I would say more important than the length of the boundary segment.

Another advantage to using road connections as a starting point is that local decisions will only be needed to add connections, not to remove them. I don't foresee instances where there is a direct highway connection between two counties that would be excluded from the list. But there are a number that would be naturally added when using a highway-based starting point (Marengo-Greene and Marengo-Dallas are good examples.)

[Torie]

I'm still confused about the matter of the size of the chop into an urban cluster, and the issue of my map going into Walker County, to accommodate microchops elsewhere. I think that flexibility should be there, but the point needs to be clarified. Good summary Muon2 of where I think we are, on matters where there is some consensus.

Walker has nothing to do with the Birmingham UCC.  So don't let that confuse you.

Since most of the population of Walker is in the northwest region, it is counted as part of the northwest region.  This gives a population of about 1.034 of the ideal.  While 3.4% is within a 5% range, it is a largish error, and might cause your plan to be excluded because other plans might have less error while using whole county regions.

The Birmingham UCC (Jefferson and Shelby) is in a 2-district region, or alternatively Jefferson is in a 1-district region, and Shelby is in an other 1-district region.

There is no problem going outside a UCC with your chops, since the regional rules should ensure compliance with the UCC for the most part.

Think of the regional map as an off-the rack suit, which you then have to fit.  You want to require the minimum amount of customization.

Do you have the population splits for Autauga, Washington, and Tuscaloosa counties?

[jimrtex]

Narrative:

In general, the 4 largest cities, Birmingham, Mobile, Huntsville, and Montgomery should have their own district, as should the Anniston, Gadsden, Talladega in the east.  The other two districts have to be made up of leftovers, including parts of the Birmingham area.

Blazer District:

Since Jefferson is close to the population for a district, and since adding no connected county would make it closer, it was made a region of its own.  Whatever is needed to make up the population difference, would be an interregional shift of a portion of a county.

It is possible to create a 2-district region centered on Jefferson (Jefferson plus the 6 adjacent  counties and Cullman is real close to 2.  This might permit either a donut plan, or a split between east and west.  But it appears to also require a rather torturous definition of the surrounding areas.  Placing Jefferson and Shelby within a single two-district region is really the same as simply attaching Jefferson to another region, before splitting it off.

Bulldog District:

I would have preferred the Tennessee River district to be to the west, Huntsville, Decatur, and Florence, but that is too populous.  Sliding it east gets the district to about the correct population.

Lion District:

Working south from Florence, enough counties were found to reach a district population.  Etowah and St.Clair could have been used rather than Tuscaloosa, but that would have split Gadsden and Anniston, and Tuscaloosa would be isolated.  The district is overpopulated to make up for the under-age for Jefferson.  

Gamecock District:

A district was created working down from DeKalb, and needed Shelby to get to the correct population (or isolating Shelby if I had continued further south.  The original plan included Cleburne, which would have given a slight over-age to the region, to make up for the deficit in Jefferson.

Jaguar District:

Mobile and Baldwin have a population equal to 7/8 of a district, and can almost be thought of as being a UCC (it is somewhat surprising that they are not a metro-area, but Baldwin has a very large share of residents who don't commute out of the county).  3 counties were added to the north, while avoiding cutting into the Black Belt.

Hornet District:

This is made up of the counties which have a BVAP of 40% or greater (actually 39.8%), including the Montgomery UCC.  Barbour and Russell were excluded to permit a corridor along the Chattahoochee from the southeastern corner of the state.  Pickens (39%) was added since it was left over after defining the Lion district.  Pike (35%) was added because it made the population of the district almost ideal, which overcome any problem with the Crenshaw hook.

The State of Alabama is prepared to defend this district against any VRA Section 2 claims.

Tiger District

This is the remainder of the state, with its irregular shape required by the creation of the Hornet district.  Roughly 1/3 of the region is in the northern part, 1/3 in the Chattahoochee corridor in 1/3 in the southeast, so it can be seen as 3 adjacent regions along the Georgia border.  The district also conforms fairly closely with three  regional councils of government.

As noted previously, Cleburne was shifted from the Gamecock to the Tiger district from the original map.  This results in 4 regions within 0.5% of the ideal.  The standard deviation is 1.69% (the original was 1.94%).  The border mileage increase from 1075 to 1087 miles.

A total of 39,727 persons (0.83% of the state population must be shifted to reach full equality, including a shift from the Jaguar district through the Tiger and Lion districts so that it can be given to the Blazer district.

The shifts into the Hornet and Gamecock districts, or from the Bulldog district do not need to be executed to get those districts within 0.5%, so they will be whole county districts.  This reduces the minimum shift to 38,606 or (0.77%) of the state population.   24,353 of this is required under any plan to get Jefferson up to the ideal population for a district, leaving 12,452 persons or 0.26% of the state's population.  This can be considered the deviation of an absolute whole-county plan.

The required shifts are:

5441 from Jaguar to Tiger in Covington (14% of the county).
7011 from Tiger to Lion in Bibb (33% of the county)
24,353 from Lion to Blazer in Tuscaloosa, Walker, or Blount (13%, 36%, or 42%, of the counties respectively).

[muon2]

Narrative:

In general, the 4 largest cities, Birmingham, Mobile, Huntsville, and Montgomery should have their own district, as should the Anniston, Gadsden, Talladega in the east.  The other two districts have to be made up of leftovers, including parts of the Birmingham area.

Blazer District:

Since Jefferson is close to the population for a district, and since adding no connected county would make it closer, it was made a region of its own.  Whatever is needed to make up the population difference, would be an interregional shift of a portion of a county.

It is possible to create a 2-district region centered on Jefferson (Jefferson plus the 6 adjacent  counties and Cullman is real close to 2.  This might permit either a donut plan, or a split between east and west.  But it appears to also require a rather torturous definition of the surrounding areas.  Placing Jefferson and Shelby within a single two-district region is really the same as simply attaching Jefferson to another region, before splitting it off.

Gamecock District:

A district was created working down from DeKalb, and needed Shelby to get to the correct population (or isolating Shelby if I had continued further south.  The original plan included Cleburne, which would have given a slight over-age to the region, to make up for the deficit in Jefferson.

Based on the usage of UCCs and regions I would say these two form one region at the initial stage. That conforms with the idea that a UCC is entirely embedded in one region. The fact that Gamecock is within 0.5% of the district quota becomes a plus when counting district-level chops, but shouldn't allow it to sit as a separate region.

I understand that you suggested a rule that a whole county region that sits within a UCC can be a separate region, but I'm not sure we have all bought into that. It biases plans towards making such a split if one was available, since that would increase the region count. I'm not sure we all want that bias. I would want to give weight to placing the chop within the UCC if that makes a more compact region centered on the UCC.

[Torie]

Just for the record, I consider the Jimtex map unacceptably erose, which just goes to reemphasize that the chop count must be balanced against erosity. I also don't like taking cognizance of the size of the micro-chops. That is an unnecessary complication, and will also lead to more erose maps if one gets credit for smaller micro-chops.

I also tend to agree with Muon2 that having more than one region (as a tool I guess) within an urban cluster probably serves no useful purpose. I also absent finding a snake hidden away, tend to be comfortable with his connectivity approach, but only for the purpose as counting as another chop appending two whole counties together that have no state highway between them. Adding an exception for a highway that gets there via another county is an unnecessary complication.

If this all gets too complicated, mostly what this effort will harvest is derision - the f'ing eggheads are off on their little algorithmic trips that nobody understands or with which one has patience, and obviously have way too much time on their hands, and need to find a real job. And oh the horror, the horror, if the end product are some of the erose maps that I see around here - then it's not only derision, but caustic derision.

And some day an erosity measure will be fashioned - some day way, way over the rainbow, way out there, and unless and until it is done, the job here is unfinished, incomplete, and flawed. So there!  

[muon2]

Defining clusters and how they should be used actually has an impact on erosity measurement. A basic tenet is that one wants there to be some parity between chop measurement and erosity to create a balance. One also want to make sure that the establishment of clusters does not force erosity into some strange corner. As I see the court at present one can't ignore population inequality entirely either since if all other measures are equal, the court is likely to insist on a plan that reduces inequality. Compactness and district design are tightly coupled to erosity as well and I find that connectivity figures into that calculation based on the tools one has to design districts.

[traininthedistance]

Just for the record, I consider the Jimtex map unacceptably erose, which just goes to reemphasize that the chop count must be balanced against erosity. I also don't like taking cognizance of the size of the micro-chops. That is an unnecessary complication, and will also lead to more erose maps if one gets credit for smaller micro-chops.

I also tend to agree with Muon2 that having more than one region (as a tool I guess) within an urban cluster probably serves no useful purpose. I also absent finding a snake hidden away, tend to be comfortable with his connectivity approach, but only for the purpose as counting as another chop appending two whole counties together that have no state highway between them. Adding an exception for a highway that gets there via another county is an unnecessary complication.

If this all gets too complicated, mostly what this effort will harvest is derision - the f'ing eggheads are off on their little algorithmic trips that nobody understands or with which one has patience, and obviously have way too much time on their hands, and need to find a real job. And oh the horror, the horror, if the end product are some of the erose maps that I see around here - then it's not only derision, but caustic derision.

And some day an erosity measure will be fashioned - some day way, way over the rainbow, way out there, and unless and until it is done, the job here is unfinished, incomplete, and flawed. So there!  

I think this post mostly goes to reemphasize your total obsession with erosity, which you appear to tilt at to the inappropriate exclusion of other legitimate factors.

My sense, when it comes to trying to create multiple apportionment regions out of one UCC, is to perhaps have a reduced bonus for it?  I.e. when scoring potential plans, being able to divide the UCC along county lines to create multiple regions could deserve a bonus, but not as much of a bonus as a plan that creates more whole-county rural apportionment regions.

As I alluded to earlier, I wonder if there should be a bonus for making whole districts entirely within counties that are too large for one district.  I don't think it should be required (in large part because I am leery of any hard requirements that aren't "comply with the VRA"), but perhaps there's a case that it should be encouraged in whatever scoring system we come up with.

[Torie]

Defining clusters and how they should be used actually has an impact on erosity measurement. A basic tenet is that one wants there to be some parity between chop measurement and erosity to create a balance. One also want to make sure that the establishment of clusters does not force erosity into some strange corner. As I see the court at present one can't ignore population inequality entirely either since if all other measures are equal, the court is likely to insist on a plan that reduces inequality. Compactness and district design are tightly coupled to erosity as well and I find that connectivity figures into that calculation based on the tools one has to design districts.

The courts will accept slighter larger micro chops if counterbalanced by other reasonable considerations, of almost any type or nature really, and that includes less erosity. On that one, I have a very high confidence level in my legal opinion.  So unless it is a tie breaker (highly unlikely), no dice for me. Sorry.