Map Projections¶
Snyder, J. P. (1987). Map Projections: A Working Manual. U.S. Geological Survey Professional Paper 1395.
Cited by¶
8 citations across 8 artifacts.
Each citation links to the sentence it supports in the citing article.
Primes¶
- Manifold
- In geography and cartography the Earth's surface is a two-dimensional manifold, locally flat for a surveyor and globally curved for a navigator, and the atlas — locally flat maps glued by transition formulae — is the cartographic instance of the mathematical concept, sharing even the same word.
This sourceTreats the Earth's curved surface mapped to flat charts via projections, each locally faithful but globally distorted -- the cartographic instance of locally flat maps glued by transition formulae.
Supported in partVerified against the work's full text
Confirms cartography maps the Earth's curved surface (treated as sphere or ellipsoid) onto flat charts, but the manual says nothing of manifolds, transition formulae, or a shared sense of 'atlas'.
“Some projections treat the Earth only as a sphere, others as either ellipsoid or sphere.”
- In geography and cartography the Earth's surface is a two-dimensional manifold, locally flat for a surveyor and globally curved for a navigator, and the atlas — locally flat maps glued by transition formulae — is the cartographic instance of the mathematical concept, sharing even the same word.
- Projection
- In cartography a spherical Earth maps to a flat plane via a chosen projection, every projection preserving some properties (angle, area, shape) and necessarily distorting others, so the choice of projection is the choice of what to lose.
This sourceStandard reference showing every map projection preserves some properties (angle, area, shape) while necessarily distorting others.
Supported in partVerified against the work's full text
Snyder shows conformal, equal-area, and equidistant projections in use, and the sphere/ellipsoid choice; the excerpt does not state that every projection distorts.
“For larger scale maps, including topographic quadrangles and the State Base Map Series, conformal projections such as the Transverse Mercator and the Lambert Conformal Conic are used. Equal-area and equidistant projections appear in the National Atlas. Other projections, such as the Miller Cylindrical and the Van der Grinten, are chosen occasionally for convenience, sometimes making use of existing base maps …”
- In cartography a spherical Earth maps to a flat plane via a chosen projection, every projection preserving some properties (angle, area, shape) and necessarily distorting others, so the choice of projection is the choice of what to lose.
- Topographic Map
- In cartography, map projections trade preservation of area, angle, and neighbourhood, and the Mercator projection has non-uniform magnification by latitude.
This sourceAuthoritative treatment of map projections and the area/angle/distance trade-offs, including Mercator's latitude-dependent magnification.
Supported in partVerified against the work's full text
Supports only that projections are chosen for what they preserve (angle, area, distance); silent on Mercator's latitude magnification and on neighbourhood.
“For larger scale maps, including topographic quadrangles and the State Base Map Series, conformal projections such as the Transverse Mercator and the Lambert Conformal Conic are used. Equal-area and equidistant projections appear in the National Atlas.”
- In cartography, map projections trade preservation of area, angle, and neighbourhood, and the Mercator projection has non-uniform magnification by latitude.
Domain-specific¶
- Albers Equal-Area Conic Projection
- Ordinarily two parallels anchor true scale and local conformality; the method does not promise that shapes or distances remain correct everywhere.
This sourceOfficial original PDF text was checked through indexed official extracts and formula cross-checks; direct full-PDF/page-image access was unavailable in the reviewing environment.
- Ordinarily two parallels anchor true scale and local conformality; the method does not promise that shapes or distances remain correct everywhere.
- Flattening
- Hammer Projection
- It halves longitude before that projection, then doubles the resulting horizontal coordinate and halves the vertical coordinate
Supported in partVerified against the source
- It halves longitude before that projection, then doubles the resulting horizontal coordinate and halves the vertical coordinate
- Oblique Mercator projection
Mechanisms¶
Verification¶
Does it exist? Confirmed. This work's DOI resolves to a registered record, which fixes its identity. That is all it fixes.
Does it back the claim? Read against the text for 4 of 8 citations: 4 supported in part. Each verdict is shown under its citation below, with what in the work backs the sentence.
Support is checked per citation rather than per work — the same source can be cited soundly in one article and wrongly in another. Per-citation recording began recently, so a citation with no recorded check is a gap in the record rather than evidence it went unchecked.
See how references were verified.
Links previously used in the corpus¶
Before the registry existed this work was also linked 1 other way.
Registry ID ref:c11d23212e29 · see in the full table