.JPGW File Extension

JPEG World File

Developer	ESRI
Popularity	Average rating 3 / 5. Vote count: 11
Category	GIS Files
Format	.JPGW
Cross Platform	Update Soon

What is an JPGW file?

A .JPGW file is a type of world file used to georeference .JPG (JPEG) images. These files are commonly used in Geographic Information Systems (GIS) to provide spatial information to an image file, allowing it to be placed accurately in the real world. The .JPGW file contains plain text with coordinate information that maps the image to a specific location on the Earth’s surface.

More Information.

The concept of world files, including .JPGW, dates back to the early developments of GIS technology. Initially, these files were used to accompany raster images to provide essential information for georeferencing. The primary purpose was to enable the integration of various raster images into GIS software, facilitating accurate mapping and spatial analysis.

Origin Of This File.

The .JPGW file extension originates from the need to georeference raster images, particularly JPEG images. This need arose within the GIS community as a way to bridge the gap between standard image formats and spatial data.

File Structure Technical Specification.

A .JPGW file typically contains six lines of plain text, each representing a specific piece of information necessary for georeferencing:

Line 1: x-dimension pixel size (width of each pixel in map units)
Line 2: Rotation term (usually 0 if the image is north-up)
Line 3: Rotation term (usually 0 if the image is north-up)
Line 4: y-dimension pixel size (height of each pixel in map units, usually negative)
Line 5: x-coordinate of the center of the upper-left pixel
Line 6: y-coordinate of the center of the upper-left pixel

How to Convert the File?

Windows

Using QGIS:
- Open QGIS.
- Load your .JPG image by going to Layer > Add Layer > Add Raster Layer.
- Once the image is loaded, go to Raster > Georeferencer.
- In the Georeferencer, load your .JPG image.
- Set the coordinate system and add ground control points (GCPs).
- Once done, click File > Start Georeferencing.
- The .JPGW file will be created in the same directory as your .JPG image.
Using ArcGIS:
- Open ArcGIS Pro or ArcMap.
- Add the .JPG image to the map.
- Use the Georeferencing toolbar to add control points.
- After georeferencing, save the image with the world file.
- The .JPGW file will be created along with the .JPG image.
Using GDAL:
- Open Command Prompt.
- Use the gdal_translate command with the -co worldfile=yes option.
- Example: gdal_translate -co worldfile=yes input.jpg output.jpg

Linux

Using QGIS:
- Follow the same steps as in the Windows section for QGIS.
Using GDAL:
- Open Terminal.
- Use the gdal_translate command with the -co worldfile=yes option.
- Example: gdal_translate -co worldfile=yes input.jpg output.jpg
Using GRASS GIS:
- Open GRASS GIS.
- Import the .JPG image using r.in.gdal.
- Set the region and georeference the image using g.gui.gcp.
- Export the image with r.out.gdal, which can create the .JPGW file.

Mac

Using QGIS:
- Follow the same steps as in the Windows section for QGIS.
Using GDAL:
- Open Terminal.
- Use the gdal_translate command with the -co worldfile=yes option.
- Example: gdal_translate -co worldfile=yes input.jpg output.jpg
Using ArcGIS Pro (via virtualization or Boot Camp):
- Follow the same steps as in the Windows section for ArcGIS.

Android

Using Mobile GIS Apps:
- Currently, there are no direct tools on Android to create .JPGW files. However, you can use desktop GIS software to create the .JPGW file and then transfer it to your Android device.
Using Remote Desktop Apps:
- Use a remote desktop app to access your desktop GIS software from your Android device and create the .JPGW file as described in the Windows or Mac sections.

iOS

Using Mobile GIS Apps:
- Similar to Android, there are no direct tools on iOS to create .JPGW files. Use desktop GIS software to create the .JPGW file and then transfer it to your iOS device.
Using Remote Desktop Apps:
- Use a remote desktop app to access your desktop GIS software from your iOS device and create the .JPGW file as described in the Windows or Mac sections.

Others

Using Web-based GIS Applications:
- Some online GIS platforms may offer tools to georeference images and create world files. You will need to check the specific platform’s documentation for details.
- Examples include ArcGIS Online, Mapbox, and Google Earth Engine.

Advantages And Disadvantages.

Advantages:

Georeferencing: Allows standard JPEG images to be used in GIS applications.
Simplicity: The plain text format is easy to read and understand.
Interoperability: Compatible with various GIS software.

Disadvantages:

Limited to Raster Images: Only works with raster images and not vector data.
Separate File: Requires the presence of both the .JPG and .JPGW files together for georeferencing.