Hi Penelope,
I have made some suggestions to Mark for how to make his commute flow tool show how all the commuters
can be accounted for. He has already made some changes and plans to make some more. He has included an “ALL” button so that all lengths of commutes can be shown if choose and not just up to 300 miles, and an “ALL” button for the CV (and not just <100%). He
said he would add the source of the data to the text and he may map the intratract commutes as well since it is helpful to visualize all the within county commutes. Do you know when the next set of tract to tract flow data will be available as he is willing
to update when available.
Thank you,
Ginger
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Turns out internal (intra-tract) flows are not reported. This should account for nearly all the missing
workers.
They may only be mapping those flows that have enough records so there is not an imputed or suppressed
O-D pair, which would mean sometimes up to 50% of the records do not have flows, so its missing half of the flows. Those show up as 0 workers due to suppression. Tom Marchwinski
I would be cautious, just did a quick check, it says ACS, but unsourced as to what ACS (I’m guessing
2009 – 2013 county to county flows – otherwise OD pairs are very tricky), also looking at just Montgomery county and DC, and expanding the tool to its maximum range (zero to 293 miles) it’s missing about half the total workers in each of those. Also, tracts
are referenced, but that set is not reported at tract. I welcome your thoughts.
Penelope Z. Weinberger
CTPP Program Manager
AASHTO
202-624-3556
ctpp.transportation.org
Check out this CTPP animation map – we didn’t make it. It’s very cool, wish we had-
http://bigbytes.mobyus.com/commute.aspx
Nancy Reger, AICP
Director, Data & Mapping
|
Mid-Ohio Regional Planning Commission
T:
614.233.4154 |
M:
614.228.2663 | nreger@morpc.org
111 Liberty Street,
Suite 100
| Columbus, OH 43215
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