JPG, JPEG, JPE

A well-known image format using .jpg, .jpeg, or .jpe extension.  JPG does not store projection information.  If a JPG image file is accompanied by a JPGW world file, Manifold will use the information in the world file, if possible, to assign an initial coordinate system.     JPG files with correctly formed JPGW world files are rare: most GIS users many years ago switched to TIFF or GeoTIFF as a GIS image format.  

 

Important:  JPG is not the same as  J2K, JPEG 2000  format, which is a more modern format that usually does assign a coordinate system on import.

 

dlg_import_jpg.png

 

By right-clicking into the Import dialog and choosing View we can ask Windows to display the files as Large icons instead of as Details.

 

dlg_import_jpg_preview.png

 

Windows will then preview the contents of .jpg files as icons.

 

To import from JPG format:

 

  1. Choose File-Import from the main menu.

  2. In the Import dialog browse to the folder containing data of interest.

  3. Double-click the file ending in .jpg or .jpeg or .jpe for the data of interest.

  4. A table and an image will be created.

 

eg_import_jpg01_01.png

 

We can double-click on images that are created to view them.   

 

eg_import_jpg01_02.png

 

This particular image shows an aerial photo of Vienna, Austria.   It is not georegistered and has no coordinate system assigned.  By default, we can assign it a Pseudo Mercator projection, which is meaningless other than to provide a coordinate system for the pixels.

 

Notes

Using graphics files -  Images in formats such as JPG that do not provide coordinate system information can be handy as illustrations in layouts or for other purposes.    Manifold project files are so efficient that we can keep libraries of many images for fast viewing in Manifold, even if we do not intend to work with them in GIS.   We can also use Manifold to convert images between different formats, importing an image as one format and exporting it as another.

 

See Also

Images

 

J2K, JPEG 2000