{{Infobox landform}}; {{Location map}}; {{OSM Location map}}

As of early 2019: OSM overlays fail to properly overlay for mobile devices. See how this page is rendered for mobile devices via https://en.m.wikipedia.org/wiki/User:J._Johnson/Sandbox3 (note the "m."). Note that first image, invoked prior to the first section header, displays okay.

And we note that adding "{{Graph:Chart||type=pie||width=0||height=0||x=0||y=0}}" anywhere in the section/article seems to fix the problem. See WP:Village_pump_(technical)#Odd_blank_map_bug_with_OSM_location_template.

Apparently "An explicit width needs to be added on the graph img tag." See https://phabricator.wikimedia.org/T216431, and also https://phabricator.wikimedia.org/T216318.

First marker test (above the section header)

small test

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75km
50miles
 
VIII
VII
VI
C
B
A
Tangshan
Sea of Bohai
Qinglong
Zunhua
Changli
Ninghe
Qinhuangdao
Tianjin
Beijing
    • Zoom = 7 **
 
 
50km
30miles
B24
B23
B22
B1
Second marker test (below the section header)

Bigger test

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Tangshan earthquake
 
 
45km
30miles
 
Sea of Bohai
Changli
Ninghe
Qinglong
Qinhuangdao
Zunhua
Tianjin
Beijing
Tangshan
    • Zoom = 8; too big. ** 2018-09-05: red: GTE, black: EHB, blue: ANSS

OSM overlay tests

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500m
550yds
 
 
Leicester Castle
 
  • Original: zoom = 14 *
 
 
200m
220yds
 
 
 
Leicester Castle
 
  • Zoom = 15. Scale mismatch. Doubling the overlay size scales up, but thickens the lines. *
 
 
500m
550yds
 
 
Leicester Castle
 
  • Base map centered at a different lat/lon, overlay at original location.*

More tests

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100km
62miles
 

Pumpkin Vine Railroad The "Pumpkin_Vine_Railroad_route.svg" overlay seems to work (following a reasonable course from the Mississippi River to Louisville via Indianapolis) if it is cut-down to quarter size (150 px high) with the map centered on the NE corner of the overlay, and zoom = 6. (Though that doesn't seem right.) At quarter size the line is too narrow, hard to see. However, the line was only 25 miles long, so the image is still over-size.