Map Projections

May 7, 2026 · View on GitHub

Any PROJ projection string can be supplied as the p.crs URL parameter on the /dali endpoint. The test suite exercises the full set of projections supported by the installed PROJ library using the map test product.

Test Product
Unsupported Projections
Projections by Type
Alphabetical Index

Test Product

The map product (test/dali/customers/test/products/map.json) renders:

A blue ocean polygon covering the full world extent
Natural Earth admin_0_countries coastlines and land fills
A 10° graticule grid

Additional per-test parameters override the projection's center (p.cx, p.cy), output size (p.xsize, p.ysize), and resolution (p.resolution, in km/pixel). Test inputs are in test/input/map_*.get and PNG renderings in docs/images/maps/.

Unsupported Projections

The following projections are listed in test/input/.testignore and excluded from the test suite.

PROJ 7 rendering defect (interrupts placed at wrong locations):

Test	PROJ String
`map_isea`	`+proj=isea`

Not working — given up on:

Test	PROJ String
`map_aeqd`	`+proj=aeqd`
`map_bertin1953`	`+proj=bertin1953`
`map_bipc`	`+proj=bipc +ns`
`map_ccon`	`+proj=ccon +lat_1=60 +lat_2=70`
`map_chamb`	`+proj=chamb +lat_1=45 +lon_1=-30 +lon_2=30`
`map_gnom`	`+proj=gnom`
`map_imw_p`	`+proj=imw_p +lat_1=30 +lat_2=60`
`map_lsat`	`+proj=lsat +lsat=1 +path=1`
`map_murd2`	`+proj=murd2 +lat_1=30 +lat_2=50`
`map_nicol`	`+proj=nicol`
`map_nsper`	`+proj=nsper +h=1000000 +lat_0=60 +lon_0=25`
`map_ob_tran`	`+proj=ob_tran +o_proj=latlong +o_lat_p=45 +o_lon_p=0 +lon_0=0`
`map_omerc`	`+proj=omerc +lat_0=45 +lonc=20 +alpha=15 +k=1 +x_0=0 +y_0=0`
`map_pconic`	`+proj=pconic +lat_1=30 +lat_2=60`
`map_peirce_q`	`+proj=peirce_q`
`map_roteqc`	`+proj=ob_tran +o_proj=eqc +o_lon_p=0 +o_lat_p=30 +lon_0=0`
`map_rotlatlon`	`+proj=ob_tran +o_proj=longlat +o_lon_p=0 +o_lat_p=30 +lon_0=0`
`map_tcc`	`+proj=tcc`
`map_tcea`	`+proj=tcea`

Note: map_bipc, map_roteqc, and map_rotlatlon do produce PNG output (shown in the alphabetical index below) but their rendering is not considered reliable.

Projections by Type

Cylindrical

Cylindrical projections map the sphere onto a cylinder.

Test	PROJ String / EPSG	Description
`map_merc`	`+proj=merc`	Mercator — conformal, shapes preserved, area greatly distorted near poles
`map_webmercator`	`EPSG:3857`	Web Mercator — de-facto standard for web tile services
`map_tmerc`	`+proj=tmerc`	Transverse Mercator — conformal, accurate along a central meridian
`map_gstmerc`	`+proj=gstmerc`	Gauss-Schreiber Transverse Mercator
`map_tobmerc`	`+proj=tobmerc`	Tobler-Mercator — variation with reduced polar distortion
`map_eqc`	`EPSG:4087`	Equidistant Cylindrical — plate carrée variant, meridians and parallels equally spaced
`map_cc`	`+proj=cc`	Central Cylindrical — perspective projection from the Earth's centre onto a cylinder
`map_cea`	`+proj=cea`	Equal-Area Cylindrical — Lambert cylindrical, preserves area
`map_mill`	`+proj=mill`	Miller Cylindrical — compromise between Mercator and equal-area
`map_comill`	`+proj=comill`	Compact Miller — reduced polar extent
`map_gall`	`+proj=gall`	Gall Stereographic — cylindrical with standard parallels at ±45°
`map_patterson`	`+proj=patterson`	Patterson Cylindrical — modern compromise projection
`map_ocea`	`+proj=ocea`	Oblique Cylindrical Equal-Area

Conic

Conic projections are well-suited for mid-latitude regions.

Test	PROJ String	Description
`map_lcc`	`+proj=lcc +lon_0=-90 +lat_1=33 +lat_2=45`	Lambert Conformal Conic — conformal, standard for aviation and NWP
`map_lcca`	`+proj=lcca +lat_0=35`	Lambert Conformal Conic Alternative
`map_aea`	`+proj=aea +lat_1=29.5 +lat_2=42.5`	Albers Equal-Area Conic — equal-area, used for US thematic maps
`map_leac`	`+proj=leac`	Lambert Equal-Area Conic
`map_eqdc`	`+proj=eqdc +lat_1=55 +lat_2=60`	Equidistant Conic — preserves distances along meridians
`map_bonne`	`+proj=bonne +lat_1=10`	Bonne — pseudo-conic equal-area
`map_cass`	`+proj=cass`	Cassini-Soldner — transverse equidistant cylindrical
`map_poly`	`+proj=poly`	American Polyconic
`map_rpoly`	`+proj=rpoly`	Rectangular Polyconic
`map_euler`	`+proj=euler +lat_1=67 +lat_2=75`	Euler
`map_tissot`	`+proj=tissot +lat_1=60 +lat_2=65`	Tissot Conic
`map_murd1`	`+proj=murd1 +lat_1=30 +lat_2=50`	Murdoch I
`map_murd3`	`+proj=murd3 +lat_1=30 +lat_2=50`	Murdoch III

Azimuthal

Azimuthal projections preserve directions from the projection centre.

Test	PROJ String / EPSG	Description
`map_laea`	`+proj=laea`	Lambert Azimuthal Equal-Area — equal-area, used for continental maps
`map_stere`	`+proj=stere +lat_0=90 +lat_ts=75`	Polar Stereographic — conformal, standard for polar regions
`map_sterea`	`+proj=sterea +lat_0=90`	Oblique Stereographic Alternative — Dutch variant used for the Netherlands
`map_arctic`	`EPSG:3995`	Arctic Polar Stereographic — standard for Arctic products
`map_antarctic`	`EPSG:3031`	Antarctic Polar Stereographic — standard for Antarctic products
`map_ups`	`+proj=ups`	Universal Polar Stereographic — polar component of the UPS military system
`map_ortho`	`+proj=ortho`	Orthographic — perspective view from infinity; globe appearance
`map_airy`	`+proj=airy`	Airy — minimum-error azimuthal
`map_rouss`	`+proj=rouss`	Roussilhe Stereographic
`map_tpers`	`+proj=tpers +h=5500000 +lat_0=40`	Tilted Perspective — satellite view from finite altitude with tilt
`map_tpeqd`	`+proj=tpeqd +lat_1=60 +lat_2=65`	Two-Point Equidistant
`map_aitoff`	`+proj=aitoff`	Aitoff — modified azimuthal, world map
`map_hammer`	`+proj=hammer`	Hammer & Eckert-Greifendorff — equal-area modified azimuthal

Pseudocylindrical

Pseudocylindrical projections have straight parallels but curved meridians.

Test	PROJ String	Description
`map_sinu`	`+proj=sinu`	Sinusoidal (Sanson-Flamsteed) — equal-area, simple formula
`map_moll`	`+proj=moll`	Mollweide — equal-area ellipse
`map_robin`	`+proj=robin`	Robinson — compromise, formerly used by National Geographic
`map_natearth`	`+proj=natearth`	Natural Earth — smooth compromise, widely used for thematic maps
`map_natearth2`	`+proj=natearth2`	Natural Earth II — variation with flatter poles
`map_natearth_shifted`	`+proj=natearth +lon_0=90`	Natural Earth (Pacific-centred)
`map_eqearth`	`+proj=eqearth`	Equal Earth — equal-area, published 2018
`map_wintri`	`+proj=wintri`	Winkel Tripel — compromise minimising distance/area/angle distortions; used by National Geographic since 1998
`map_wink1`	`+proj=wink1`	Winkel I
`map_wink2`	`+proj=wink2`	Winkel II
`map_eck1`	`+proj=eck1`	Eckert I
`map_eck2`	`+proj=eck2`	Eckert II
`map_eck3`	`+proj=eck3`	Eckert III
`map_eck4`	`+proj=eck4`	Eckert IV — equal-area
`map_eck5`	`+proj=eck5`	Eckert V
`map_eck6`	`+proj=eck6`	Eckert VI — equal-area
`map_wag1`	`+proj=wag1`	Wagner I — equal-area
`map_wag2`	`+proj=wag2`	Wagner II
`map_wag3`	`+proj=wag3`	Wagner III
`map_wag4`	`+proj=wag4`	Wagner IV — equal-area
`map_wag5`	`+proj=wag5`	Wagner V
`map_wag6`	`+proj=wag6`	Wagner VI
`map_wag7`	`+proj=wag7`	Wagner VII — equal-area azimuthal hybrid
`map_kav5`	`+proj=kav5`	Kavraiskiy V
`map_kav7`	`+proj=kav7`	Kavraiskiy VII
`map_crast`	`+proj=crast`	Craster Parabolic — equal-area
`map_boggs`	`+proj=boggs`	Boggs Eumorphic — equal-area
`map_hatano`	`+proj=hatano`	Hatano Asymmetrical Equal-Area — different standard parallels in N and S hemispheres
`map_fouc`	`+proj=fouc`	Foucaut — equal-area
`map_fouc_s`	`+proj=fouc_s`	Foucaut Sinusoidal — blend of sinusoidal and cylindrical
`map_qua_aut`	`+proj=qua_aut`	Quartic Authalic — equal-area
`map_nell`	`+proj=nell`	Nell
`map_nell_h`	`+proj=nell_h`	Nell-Hammer
`map_loxim`	`+proj=loxim`	Loximuthal
`map_putp1`	`+proj=putp1`	Putnins P1
`map_putp2`	`+proj=putp2`	Putnins P2
`map_putp3`	`+proj=putp3`	Putnins P3
`map_putp3p`	`+proj=putp3p`	Putnins P3'
`map_putp4p`	`+proj=putp4p`	Putnins P4'
`map_putp5`	`+proj=putp5`	Putnins P5
`map_putp5p`	`+proj=putp5p`	Putnins P5'
`map_putp6`	`+proj=putp6`	Putnins P6
`map_putp6p`	`+proj=putp6p`	Putnins P6'
`map_collg`	`+proj=collg`	Collignon — equal-area triangle shape
`map_denoy`	`+proj=denoy`	Denoyer Semi-Elliptical
`map_fahey`	`+proj=fahey`	Fahey
`map_gn_sinu`	`+proj=gn_sinu +m=2 +n=3`	General Sinusoidal Series
`map_urmfps`	`+proj=urmfps +n=0.5`	Urmaev Flat-Polar Sinusoidal
`map_urm5`	`+proj=urm5 +n=0.9 +alpha=2 +q=4`	Urmaev V
`map_weren`	`+proj=weren`	Werenskiold I
`map_larr`	`+proj=larr`	Larrivée
`map_lask`	`+proj=lask`	Laskowski
`map_times`	`+proj=times`	Times
`map_mbt_fps`	`+proj=mbt_fps`	McBryde-Thomas Flat-Polar Sinusoidal — equal-area
`map_mbtfps`	`+proj=mbtfps`	McBryde-Thomas Flat-Polar Sinusoidal (alt.) — equal-area
`map_mbt_s`	`+proj=mbt_s`	McBryde-Thomas Flat-Polar Sinusoidal (var.) — equal-area
`map_mbtfpp`	`+proj=mbtfpp`	McBryde-Thomas Flat-Polar Parabolic — equal-area
`map_mbtfpq`	`+proj=mbtfpq`	McBryde-Thomas Flat-Polar Quartic — equal-area

Globular and Polyhedral

These projections use unconventional boundaries for artistic or special purposes.

Test	PROJ String	Description
`map_adams_hemi`	`+proj=adams_hemi`	Adams Hemisphere-in-a-Square — conformal, entire hemisphere in a square
`map_adams_ws1`	`+proj=adams_ws1`	Adams World in a Square I — conformal world map in a square
`map_adams_ws2`	`+proj=adams_ws2`	Adams World in a Square II
`map_apian`	`+proj=apian`	Apian Globular I
`map_bacon`	`+proj=bacon`	Bacon Globular
`map_ortel`	`+proj=ortel`	Ortelius Oval
`map_august`	`+proj=august`	August Epicycloidal — conformal world-in-a-circle
`map_lagrng`	`+proj=lagrng`	Lagrange — conformal in a circle
`map_gins8`	`+proj=gins8`	Ginsburg VIII
`map_healpix`	`+proj=healpix`	HEALPix — hierarchical equal-area pixelization; used in astrophysics and CMB analysis

Van der Grinten

Test	PROJ String	Description
`map_vandg`	`+proj=vandg`	Van der Grinten I — world in a circle
`map_vandg2`	`+proj=vandg2`	Van der Grinten II
`map_vandg3`	`+proj=vandg3`	Van der Grinten III
`map_vandg4`	`+proj=vandg4`	Van der Grinten IV

Interrupted

Interrupted projections break the map along selected meridians to reduce distortion in landmasses or oceans.

Test	PROJ String	Description
`map_igh`	`+proj=igh`	Goode Interrupted Homolosine — equal-area, interrupts over oceans
`map_igh_o`	`+proj=igh_o +lon_0=-160`	Goode Interrupted Homolosine (Oceans) — interrupts over land, shows ocean continuity
`map_igh_shifted`	`+proj=igh +lon_0=90`	Goode Interrupted Homolosine (shifted 90° E)
`map_goode`	`+proj=goode`	Goode Homolosine (uninterrupted)

Satellite and Perspective

Test	PROJ String	Description
`map_geos`	`+proj=geos +h=35785831 +lon_0=-60 +sweep=y`	Geostationary Satellite View — view from 35786 km altitude over the Atlantic
`map_tpers`	`+proj=tpers +h=5500000 +lat_0=40`	Tilted Perspective — view from 5500 km altitude with tilt
`map_mil_os`	`+proj=mil_os`	Miller Oblated Stereographic — used for European maps

Alphabetical Index

Test	PROJ String / EPSG	PROJ Docs
`map_adams_hemi`	`+proj=adams_hemi`	Adams Hemisphere-in-a-Square
`map_adams_ws1`	`+proj=adams_ws1`	Adams World in a Square I
`map_adams_ws2`	`+proj=adams_ws2`	Adams World in a Square II
`map_aea`	`+proj=aea +lat_1=29.5 +lat_2=42.5`	Albers Equal-Area Conic
`map_airy`	`+proj=airy`	Airy
`map_aitoff`	`+proj=aitoff`	Aitoff
`map_antarctic`	`EPSG:3031`	Polar Stereographic (South)
`map_apian`	`+proj=apian`	Apian Globular I
`map_arctic`	`EPSG:3995`	Arctic Polar Stereographic
`map_august`	`+proj=august`	August Epicycloidal
`map_bacon`	`+proj=bacon`	Bacon Globular
`map_bipc` ⚠	`+proj=bipc +ns`	Bipolar Conic of Western Hemisphere
`map_boggs`	`+proj=boggs`	Boggs Eumorphic
`map_bonne`	`+proj=bonne +lat_1=10`	Bonne
`map_cass`	`+proj=cass`	Cassini-Soldner
`map_cc`	`+proj=cc`	Central Cylindrical
`map_cea`	`+proj=cea`	Equal-Area Cylindrical
`map_collg`	`+proj=collg`	Collignon
`map_comill`	`+proj=comill`	Compact Miller
`map_crast`	`+proj=crast`	Craster Parabolic
`map_denoy`	`+proj=denoy`	Denoyer Semi-Elliptical
`map_eck1`	`+proj=eck1`	Eckert I
`map_eck2`	`+proj=eck2`	Eckert II
`map_eck3`	`+proj=eck3`	Eckert III
`map_eck4`	`+proj=eck4`	Eckert IV
`map_eck5`	`+proj=eck5`	Eckert V
`map_eck6`	`+proj=eck6`	Eckert VI
`map_eqc`	`EPSG:4087`	Equidistant Cylindrical
`map_eqdc`	`+proj=eqdc +lat_1=55 +lat_2=60`	Equidistant Conic
`map_eqearth`	`+proj=eqearth`	Equal Earth
`map_euler`	`+proj=euler +lat_1=67 +lat_2=75`	Euler
`map_fahey`	`+proj=fahey`	Fahey
`map_fouc`	`+proj=fouc`	Foucaut
`map_fouc_s`	`+proj=fouc_s`	Foucaut Sinusoidal
`map_gall`	`+proj=gall`	Gall Stereographic
`map_geos`	`+proj=geos +h=35785831 +lon_0=-60 +sweep=y`	Geostationary Satellite View
`map_gins8`	`+proj=gins8`	Ginsburg VIII
`map_gn_sinu`	`+proj=gn_sinu +m=2 +n=3`	General Sinusoidal Series
`map_goode`	`+proj=goode`	Goode Homolosine
`map_gstmerc`	`+proj=gstmerc`	Gauss-Schreiber Transverse Mercator
`map_hammer`	`+proj=hammer`	Hammer & Eckert-Greifendorff
`map_hatano`	`+proj=hatano`	Hatano Asymmetrical Equal-Area
`map_healpix`	`+proj=healpix`	HEALPix
`map_igh`	`+proj=igh`	Goode Interrupted Homolosine
`map_igh_o`	`+proj=igh_o +lon_0=-160`	Goode Interrupted Homolosine (Oceans)
`map_igh_shifted`	`+proj=igh +lon_0=90`	Goode Interrupted Homolosine (shifted)
`map_isea` ⚠	`+proj=isea`	Icosahedral Snyder Equal-Area
`map_kav5`	`+proj=kav5`	Kavraiskiy V
`map_kav7`	`+proj=kav7`	Kavraiskiy VII
`map_laea`	`+proj=laea`	Lambert Azimuthal Equal-Area
`map_lagrng`	`+proj=lagrng`	Lagrange
`map_larr`	`+proj=larr`	Larrivée
`map_lask`	`+proj=lask`	Laskowski
`map_lcc`	`+proj=lcc +lon_0=-90 +lat_1=33 +lat_2=45`	Lambert Conformal Conic
`map_lcca`	`+proj=lcca +lat_0=35`	Lambert Conformal Conic Alternative
`map_leac`	`+proj=leac`	Lambert Equal-Area Conic
`map_loxim`	`+proj=loxim`	Loximuthal
`map_mbt_fps`	`+proj=mbt_fps`	McBryde-Thomas Flat-Polar Sinusoidal
`map_mbt_s`	`+proj=mbt_s`	McBryde-Thomas Flat-Polar Sinusoidal (var.)
`map_mbtfpp`	`+proj=mbtfpp`	McBryde-Thomas Flat-Polar Parabolic
`map_mbtfpq`	`+proj=mbtfpq`	McBryde-Thomas Flat-Polar Quartic
`map_mbtfps`	`+proj=mbtfps`	McBryde-Thomas Flat-Polar Sinusoidal (alt.)
`map_merc`	`+proj=merc`	Mercator
`map_mil_os`	`+proj=mil_os`	Miller Oblated Stereographic
`map_mill`	`+proj=mill`	Miller Cylindrical
`map_moll`	`+proj=moll`	Mollweide
`map_murd1`	`+proj=murd1 +lat_1=30 +lat_2=50`	Murdoch I
`map_murd3`	`+proj=murd3 +lat_1=30 +lat_2=50`	Murdoch III
`map_natearth`	`+proj=natearth`	Natural Earth
`map_natearth2`	`+proj=natearth2`	Natural Earth II
`map_natearth_shifted`	`+proj=natearth +lon_0=90`	Natural Earth (Pacific-centred)
`map_nell`	`+proj=nell`	Nell
`map_nell_h`	`+proj=nell_h`	Nell-Hammer
`map_ocea`	`+proj=ocea`	Oblique Cylindrical Equal-Area
`map_ortel`	`+proj=ortel`	Ortelius Oval
`map_ortho`	`+proj=ortho`	Orthographic
`map_patterson`	`+proj=patterson`	Patterson Cylindrical
`map_poly`	`+proj=poly`	American Polyconic
`map_putp1`	`+proj=putp1`	Putnins P1
`map_putp2`	`+proj=putp2`	Putnins P2
`map_putp3`	`+proj=putp3`	Putnins P3
`map_putp3p`	`+proj=putp3p`	Putnins P3'
`map_putp4p`	`+proj=putp4p`	Putnins P4'
`map_putp5`	`+proj=putp5`	Putnins P5
`map_putp5p`	`+proj=putp5p`	Putnins P5'
`map_putp6`	`+proj=putp6`	Putnins P6
`map_putp6p`	`+proj=putp6p`	Putnins P6'
`map_qua_aut`	`+proj=qua_aut`	Quartic Authalic
`map_robin`	`+proj=robin`	Robinson
`map_roteqc` ⚠	`+proj=ob_tran +o_proj=eqc +o_lon_p=0 +o_lat_p=30 +lon_0=0`	Rotated Equidistant Cylindrical
`map_rotlatlon` ⚠	`+proj=ob_tran +o_proj=longlat +o_lon_p=0 +o_lat_p=30 +lon_0=0`	Rotated Geographic
`map_rouss`	`+proj=rouss`	Roussilhe Stereographic
`map_rpoly`	`+proj=rpoly`	Rectangular Polyconic
`map_sinu`	`+proj=sinu`	Sinusoidal (Sanson-Flamsteed)
`map_stere`	`+proj=stere +lat_0=90 +lat_ts=75`	Stereographic (polar, true scale at 75°N)
`map_sterea`	`+proj=sterea +lat_0=90`	Oblique Stereographic Alternative
`map_times`	`+proj=times`	Times
`map_tissot`	`+proj=tissot +lat_1=60 +lat_2=65`	Tissot Conic
`map_tmerc`	`+proj=tmerc`	Transverse Mercator
`map_tobmerc`	`+proj=tobmerc`	Tobler-Mercator
`map_tpeqd`	`+proj=tpeqd +lat_1=60 +lat_2=65`	Two-Point Equidistant
`map_tpers`	`+proj=tpers +h=5500000 +lat_0=40`	Tilted Perspective
`map_ups`	`+proj=ups`	Universal Polar Stereographic
`map_urm5`	`+proj=urm5 +n=0.9 +alpha=2 +q=4`	Urmaev V
`map_urmfps`	`+proj=urmfps +n=0.5`	Urmaev Flat-Polar Sinusoidal
`map_vandg`	`+proj=vandg`	Van der Grinten I
`map_vandg2`	`+proj=vandg2`	Van der Grinten II
`map_vandg3`	`+proj=vandg3`	Van der Grinten III
`map_vandg4`	`+proj=vandg4`	Van der Grinten IV
`map_wag1`	`+proj=wag1`	Wagner I
`map_wag2`	`+proj=wag2`	Wagner II
`map_wag3`	`+proj=wag3`	Wagner III
`map_wag4`	`+proj=wag4`	Wagner IV
`map_wag5`	`+proj=wag5`	Wagner V
`map_wag6`	`+proj=wag6`	Wagner VI
`map_wag7`	`+proj=wag7`	Wagner VII
`map_webmercator`	`EPSG:3857`	Web Mercator
`map_weren`	`+proj=weren`	Werenskiold I
`map_wink1`	`+proj=wink1`	Winkel I
`map_wink2`	`+proj=wink2`	Winkel II
`map_wintri`	`+proj=wintri`	Winkel Tripel

⚠ = listed in .testignore; output may be rendered but is not considered reliable.