JGW File – What is .jgw file and how to open it?
JGW File Extension
JPEG World File – file format by ESRI
A JGW file is a world file format used by ESRI to store geographic information about a raster image. It contains information about the image’s location on the Earth’s surface, its rotation, and its scale. It is commonly used in geographic information systems (GIS) to align raster images with other geographic data.
JGW File: Overview and Purpose
A JGW file is known as a JPEG World File, commonly associated with geospatial data. It’s an ASCII text file that accompanies a JPEG image containing geographic information. The primary purpose of a JGW file is to provide georeferencing information, allowing the image to be correctly positioned and aligned in a Geographic Information System (GIS).
Structure and Content of a JGW File
A JGW file consists of six numerical values arranged in two rows. The first three values represent the affine transformation coefficients, which define the transformation from pixel coordinates to geographic coordinates. The fourth and fifth values indicate the x and y coordinates of the pixel in the upper-left corner of the image, while the sixth value is the pixel size in the x direction. These values facilitate the accurate positioning of the JPEG image within a GIS, ensuring its proper alignment with other geospatial data.
What is a JGW File?
A JGW file, also known as a JPEG World File, is a georeferencing file that stores the geocoding information for a corresponding JPEG image. It contains information about the image’s location, orientation, and scale on the earth’s surface. A JGW file typically uses the same name as the JPEG image it references, with a .jgw extension. It provides a way to link an image to a specific location and geographic coordinate system, enabling it to be accurately overlaid on maps and other geographic data.
How to Open a JGW File
To open a JGW file, you can use a geographic information system (GIS) software or online tools that support geospatial data handling. Some common GIS software that supports JGW files include ArcGIS, QGIS, and GDAL. These software programs provide tools for viewing and manipulating georeferenced images, allowing users to overlay them on maps, perform spatial analysis, and export data in various formats. Online tools such as Georeferencer.org and MapTiler also allow you to view and download geocoded JPEG images by providing the JGW file and the corresponding JPEG image.
Definition and Purpose
A JPEG World File (JGW) is a metadata file that provides geographic referencing information for a corresponding JPEG image. It is commonly used in geospatial applications to align georeferenced rasters with a real-world coordinate system. JGW files are typically named the same as the associated JPEG image, with a .jgw extension.
Structure and Format
JGW files are plain text files that contain six affine transformation coefficients, which define the relationship between the image pixel coordinates and the corresponding geographic coordinates. These coefficients are arranged in a specific order:
- A: Horizontal pixel size in map units
- B: Skew in map units
- C: Skew in map units
- D: Vertical pixel size in map units
- E: X displacement in map units
- F: Y displacement in map units
The coefficients are given in the same units as the geographic coordinate system specified in the JGW file (e.g., meters, degrees). The file also includes a line with the projection information (e.g., EPSG:3857). By applying these coefficients to the pixel coordinates, georeferenced rasters can be precisely positioned within a geographic information system (GIS) or other geospatial software.