[Talk-us] Remapping is good

Alan Mintz Alan_Mintz+OSM at Earthlink.Net
Mon Apr 2 23:42:09 BST 2012

At 2012-01-31 13:52, Nick Hocking wrote:
>This morning I decided to remap another street off Cypress Avenue L.A.
>I randomly choose "Ariva Street" and lo and behold the TIGER2011
>overlay said that it was Arvia Street.
>TIGER is usually spot on with names and since a Bing search and Google
>maps/street view also agree about "Arvia" this street is now correctly
>named (courtesy of TIGER).

Sorry I missed this earlier...

1. I've researched many hundreds of naming issues in southern Cal. I can't 
give you a specific percentage, but neither TIGER05 nor TIGER11 could be 
considered "usually spot on", nor could most other sources.

2. AFAIK, you cannot use Google Maps/Earth as a source for naming, due to 
licensing. Same applies to Bing Maps, though we are specifically allowed 
use of their satellite imagery. Using them, anyway, would just be repeating 
an unknown source - not necessarily conducive to better map quality.

3. For LA County, there are great online sources of public records:

3a. Tract Maps: 
http://gis.dpw.lacounty.gov/website/SurveyRecord/tractMain.cfm and 
http://gis.dpw.lacounty.gov/landrecords/index.cfm?docType=TM and parcel 
maps: http://gis.dpw.lacounty.gov/website/SurveyRecord/parcelMain.cfm and 
http://gis.dpw.lacounty.gov/landrecords/index.cfm?docType=PM . These are 
"official" and should generally be given the most weight, particularly 
newer ones. Tract maps are preferable to parcel maps Streets that surround 
the subject tract or parcel will occasionally have mistakes in them. I tag 
objects based on these with source=LACDPW + source_ref=TRbbbb-ppp or 
MBbbbb-ppp for tract maps, or PMbbb-ppp for parcel maps.

3b. Assessor's maps: http://maps.assessor.lacounty.gov/mapping/viewer.asp 
Note that the basemap used in the viewer is not necessarily accurate, as 
it's sourced from a different place than the official assessor's maps. Find 
a property parcel along the street you want and use the (i)nfo tool to 
select it. Then, click on the "Click here to view Assessor's Map", which 
will open a PDF map 
where bbbb is the 0-padded book number and ppp is the 0-padded page number 
(there are some exceptions to this format for very old areas). I tag 
objects based on these with source=LACA + source_ref=ABKbbbb-ppp or AMbbbb-ppp.

3c. You can check a parcel address against the USPS address database here: 
https://tools.usps.com/go/ZipLookupAction!input.action (not sure about 
legality here - it's arguable).

3d. Photo survey. A good old local observation of the street sign(s), 
hopefully with photo evidence can be helpful. I tag these 
source=survey;image + source_ref=AM909_DSCxyyyy (my picture number). Do 
note, though, that these are sometimes "wrong" (particularly street type). 
However, they at least warrant an alt_name tag until they are corrected. 
When I find incorrect signs, I generally research the responsible authority 
(incorporated city or county) and tell them about it.

There are often instances where you have to decide which is correct, or you 
can't, in which case you should add an alt_name tag, all your source tags 
(semi-colon separated), and a note tag to explain the research done.

Don't forget to remove the tiger:reviewed tag from ways you verify or edit, 

>If people are going to spend an entire night armchair mapping,
>wouldn't it be great if they all remapped L.A.

Maybe. As always, please look at the existing description, note, source and 
source_ref tags and/or history to see previous edits. It's not nice to 
incorrectly armchair-edit an object that someone else spent some time 
researching. Ways with tiger:reviewed tags (highlighted in various editors) 
are a good start, as they have usually not been edited.

Alan Mintz <Alan_Mintz+OSM at Earthlink.net>

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