The national topographic record: the survey's own sheets

The 15-minute beginnings and the 7.5-minute quadrangles

The frame. The U.S. Geological Survey's topographic program is the one map series in this section made to a national standard by a national bureau, preserved whole in the Survey's Historical Topographic Map Collection — over 185,000 scanned sheets, printed between 1884 and 2006, free to download with the current US Topo series that succeeded them in 2009. Northern Indiana was late to the program. The earliest national topographic sheet touching this county in the indexed record is the 15-minute Niles quadrangle of 1927, which covers the county's northern tier across the state line; the city itself waited for the postwar program.

The 7.5-minute editions. The Illinois State Library's inventory of superseded USGS quadrangles — the standard checklist of the printed editions — gives the county's city sheets their dates. South Bend East (quad 41086-F2): first edition 1958, a new edition 1969, photorevisions of 1980 and 1986, and a 1991 printing. Osceola (41086-F1), the quad east of it: 1958 and 1969, photorevised 1980 and 1986. South Bend West (41086-F3), carrying the town toward New Carlisle: a 1969 first edition and a 1980 photorevision in the inventory. There is no Mishawaka quadrangle: the neighboring city lies across the South Bend East and Osceola sheets, a boundary fact the national grid states without comment. A photorevision, for the record, is the Survey's economy measure — new aerial photography read onto the old sheet in purple, change without resurvey — and the 1980 and 1986 purple editions are the Studebaker plant's topographic afterlife: the great works fading from the standard map by revision as they were razed on the ground.

The digital succession. The US Topo series rebuilt the quadrangle as a digital file, layered from the national databases and current aerial imagery. Two editions of the South Bend East file were read for this section: the 2010 US Topo, carrying National Agriculture Imagery Program photography of August 2008 and produced to the series' draft standard 0.5.10, and the 2013 edition, on imagery of January 2010. The paper quadrangle's century ends there — the map of record is a file, revised on the imagery's cycle, and the Historical Topographic Map Collection keeps the printed run as the archive this section began with.

Sources:

1. Illinois State Library, Historical Topographic Quadrangles of Indiana (Scale 1:24,000) — the edition inventory for South Bend East (41086-F2: 1958; 1969; 1980 PR; 1986 PR; 1991), South Bend West (41086-F3: 1969; 1980 PR) and Osceola (41086-F1: 1958; 1969; 1980 PR; 1986 PR).
2. U.S. Geological Survey, Historical Topographic Maps — Preserving the Past (National Geospatial Program) — the Historical Topographic Map Collection's scope (1884–2006; 185,000+ files) and the US Topo succession.
3. US Topo files, South Bend East quadrangle, editions of 2010 and 2013 (USGS, via the National Map) — imagery dates and production standard as printed on the files.
4. USGS-derived commercial indexes of the county's topographic holdings — the 1927 Niles 15-minute quadrangle as the earliest sheet touching the county.