LinuxWhat is the JGW file format?
.jgw is a geospatial information format that stores data in plain text. A .jgw file contains exactly six numeric lines - capturing pixel scale, rotation/skew coefficients, and the coordinates of the centre of the upper-left pixel. Data in .jgw files allow GIS software to reconstruct the real-world position of every pixel in the paired image on a map. The .jpg image referenced by a .jgw file typically stores an aerial or orthophoto view used for generating orthophoto maps.
The .jgw is a sidecar file - it carries no pixel data of its own and must reside alongside a JPEG of the same base name. The coordinate reference system is not stored inside the .jgw; it lives in a companion .prj file or an .aux.xml sidecar. The extension follows the world-file naming pattern: first and last letters of the image extension plus "w" - jpg → .jgw. The same convention gives .tfw for TIFF world files and .pgw for PNG.
Orthophotomap
An orthophotomap is a map image created from a collection of raster images and additional georeferencing data. Orthophotomaps use images adjusted for camera tilt and Earth curvature to achieve uniform scale. Orthophotomaps are used to track geographical changes and confirm the existence of objects marked on maps. Orthophotomap imagery referenced by .jgw files should not be confused with raw satellite images.
Security & safety
RISK: LOWA JGW is a tiny plain-text file with six numbers - it cannot contain or execute code and carries no privacy data beyond the map coordinates of the associated image. The only real 'risk' is operational: deleting or mismatching the .jgw leaves the JPEG un-georeferenced (it opens as a plain picture but won't line up on the map), and editing the numbers carelessly shifts the image off-position. Keep the .jgw with its same-named JPEG, and remember a JPEG is lossy - don't re-save the image repeatedly.
Format details
in a nutshellPrograms that open JGW files
Windows5 apps
AutoCAD Map 3D
Paid Insert the JPEG as a georeferenced raster image; the .jgw is read automatically to position it. The db-recommended tool, now part of AutoCAD with the Map 3D toolset. 
QGIS
Open-source Add the .jpg (Layer -> Add Raster Layer); QGIS reads the sibling .jgw automatically to place it. The free, standard GIS tool.
ArcGIS Pro
Paid Add the JPEG to a map; the .jgw is applied automatically. Esri's current desktop product (ArcMap retired).
Any text editor (Notepad, Notepad++)
Free Open the .jgw to read or edit the six georeferencing numbers directly - it's plain text. The db lists 'Text editor' here, which is correct.
GDAL (gdalinfo / gdal_translate)
Open-source Command-line: 'gdalinfo map.jpg' shows the georeferencing read from the .jgw; gdal_translate can embed it into a GeoTIFF. 
macOS1 app
Technical details
deep spec| File structure | Exactly six plain-text lines; no header, no delimiter, no binary content |
| Text encoding | ASCII / UTF-8; one decimal number per line |
| Coefficient A - pixel width | X-component of pixel size in map units per pixel along the column direction (line 1) |
| Coefficient D - row rotation | Rotation parameter around the X axis; 0.0 in north-up, non-rotated images (line 2) |
| Coefficient B - column rotation | Rotation parameter around the Y axis; 0.0 in north-up, non-rotated images (line 3) |
| Coefficient E - pixel height | Y-component of pixel size in map units per pixel; always negative for top-to-bottom raster rows (line 4) |
| Coefficient C - X origin | X coordinate of the centre of the upper-left pixel in the map's projected units (line 5) |
| Coefficient F - Y origin | Y coordinate of the centre of the upper-left pixel in the map's projected units (line 6) |
| MIME type | text/plain |
| Typical file size | Under 200 bytes (six short numeric lines) |
| Paired image requirement | Must share the same base name as its companion .jpg or .jpeg file in the same directory |
| Coordinate reference system | Not stored in the .jgw; defined separately in a companion .prj file or .aux.xml sidecar |
| Transform model | 2D affine transform encoding scale, rotation and translation - does not correct for lens distortion or terrain relief |
| Extension naming rule | First and last letters of the image extension plus 'w': jpg → .jgw (four-letter variant .jpgw also used) |
| Platform support | Any platform (plain text); natively read by GDAL, QGIS, ArcGIS Pro, AutoCAD Map 3D and most GIS toolchains |
| Georeferencing alternative | Georeferencing can instead be embedded in an .aux.xml sidecar or as a GeoJPEG, but the .jgw sidecar remains the dominant practice |
| Released | Early 1990s with Esri ArcView; the world-file convention is a de facto GIS standard |
| Latest version | N/A (a 6-line text convention; unchanged since introduction) |
| Open standard | Yes · royalty-free |
| Specification | en.wikipedia.org |
JGW conversions
Community Q&A
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