On 2019-01-28 12:40, OSM Volunteer stevea wrote:
(Lengthy reply alert)
Hi Minh:
Thanks for your (always thorough and well-researched) pointers and history — though I don't recall
"impressing LAFCO" upon you, I did mention it in the context of admin_level, so, OK,
whatever! Good for Santa Clara LAFCO for publishing municipal boundaries into the PD. I am again
thankful we live in a state with excellent public data in the PD along with our "sunshine
laws."
I like that you made Seven Trees an admin_level=10 for reasons you did, even as you've
described other SJ neighborhoods as "amorphous" (exactly the right word, imo!)
I wouldn't have noticed had you not sent me links [1].
"Urban islands as a LAFCO high priority to streamline" is something I've never heard of before. Notwithstanding the
letter LAFCO sent City of San José nearly eight years ago [3], I believe it is the City of San José itself which "serves as
the authority on" its own municipal boundary. LAFCO might have something to say (keeping accurate maps / GIS data, for
example) about all cities in Santa Clara County, but I don't think anyone contends that LAFCO doesn't define municipal
boundaries, the cities themselves do. Indeed, LAFCO's letter says it can "encourage" annexations (of islands) and
waive its fees (to incentivize a "streamlined process" for islands 150 acres or less) but it cannot force a city to do
so, whether this is a "high priority" for the LAFCO or not.
Using link [4] and blending with the instant topic (which I volunteered to remedy), I examined the five pages of City of Santa Clara. The first four
(pages 45-48) are "islands" which share a boundary with City of San José (the fifth is an island solely inside of the City of Santa Clara).
None of these involve the area around the airport / Westfield Valley Fair, which was Andy Townsend's "area of concern," prompting me to
answer that I'd take a look. (SC05, page 48, is pretty close, but is north of the airport and involves a creek edge near Trimble and Orchard).
Those four "islands" probably could be used to (rather crudely) "hand draw modify" the Santa Clara City Limit boundary in OSM
(relation 2221647) but it isn't clear to me how what these maps define as Urban Service Boundary is or isn't the actual city limit boundary for Santa
Clara. As I think about it, the identification of these four islands (the fifth might become an "inner" member of that relation) in this
document COULD be used to exclude these islands from the City Limit, but I'm not sure that is accurate (it likely is, I'm simply not sure). So while
these resources might qualify as "interesting," I don't find them wholly relevant to what I volunteered to do "near the airport."
However, links [5] and especially [6] yield dense, recent, tasty data. Having used
ArcGIS layers before like this (largely while mapping to fix TIGER rail), I can set a
basemap of OSM while viewing these data. Doing so allows me to find where there are some
relatively minor differences, so I elected to fix these, "manually" using JOSM.
These (minor) changes were along the "grass edge" NW of the 101-Trimble interchange, westerly to the UP Coast
Subdivision rail bridge crossing 101, southerly to just north of Central Expressway (not south, a significant change
making OSM's representation of CE W of Trimble/De La Cruz to the rail bridge now in Santa Clara, not San José). This
continues easterly across Trimble into the airport, as far as Taxiway Y, includes better-traced (though likely not
perfectly accurate) rectangular and triangular areas of northern portions of runways and taxiways, south along De La
Cruz and excludes Memorial Cross Park (in San José, not Santa Clara). The barrier=fence had to be node-by-node unglued
from the city limit (but kept glued to the parking lot) to be better characterized as "along Martin Avenue"
(and so was), SE on Martin Avenue (with some "jogs") to a bit further SE on Aviation Avenue, southerly (with
"jogs") to Campbell Avenue near Stephen Schott Stadium.
From there, the boundary needed to be moved easterly by about 10 meters, so it
was, past Sherwood and along Portola Avenue. Adjustments were made to better
align with The Alameda, past Morse and Idaho and to I-880, where a 90-degree
westerly boundary continues to Newhall and Monroe, where as it follows the
southern boundary of Santa Clara Mission Cemetery, it is correct (enough for
now).
The ways I changed have IDs 166659029 and 97341711 (recently reverted by Andy Townsend),
part of the Santa Clara (city) municipal boundary relation. I believe this is moderately
better, which is "moderately better."
SteveA
Thanks for making these improvements! I've added an item to our local
to-do lists for refining the rest of the city boundary as needed:
https://github.com/codeforsanjose/OSM-SouthBay/issues/19
https://wiki.openstreetmap.org/wiki/Special:Diff/1782398
--
m...@nguyen.cincinnati.oh.us
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