JPE is the graphic format of the raster image category. It was developed by the standards committee of the Joint Photographic Experts Group. It is a 24-bit compressed graphics format. Typically, it is used for web resources. In most cases, it is used for photographs or images in which there are many colors. Also well suited for many digital cameras to store digital photos. Images that have this extension use lossy compression. And because the quality of individual photos is getting worse. The greater the compression, the less quality the image becomes. The purpose of JPE files is to compress photorealistic images with small color losses. Provides the ability to achieve high compression ratios. We emphasize that usually the maximum compression of graphic information leads to some loss of information. That is, the compression algorithm changes the original data so that the image that is obtained after restoration will be different from the original image, that is, compressed. This compression method is used to work with full-color images that have high photographic quality. During compression, the Discrete-Cosine Transform (DCT), Huffman’s Code quantization and coding are used.
JNX is a raster map format. It refers to the so-called tile formats, by which you need to understand a large-scale raster image on the map, divided into smaller rectangular parts. This is necessary so that the display of the navigator is accelerated. JNX files are used on Garmin devices to display satellite maps that are available through BirdsEye subscription. In devices for these files, space is allocated on the internal drive in the Garmin \ BirdsEye folder or on the SD card. The coordinates are stored in the form of signed 4-byte integers. The coordinates of the two corners of the map describe two pairs of numbers: one is latitude, the second is longitude. Tiles are standard JPG drawings. Their lion's share in BirdsEye cards is with a resolution of 256 by 256 pixels. There is support for images and larger. Devices are endowed with the ability to display tiles up to 1 megapixel in size. If the sizes go beyond this limit, then the image is automatically reduced with a loss of quality. There is a significant limitation of the JNX format. Such is the rigid binding of cards to a specific device. The JNX format is fully explored. An exception is only part of the loader service data block. However, when you create your own maps, this can be neglected. There is a set of utilities with which you can convert raster maps to JNX format. They serve for reverse conversion. Files in the JNX format have a binding code for the device. Despite this, there are ways to use your own JNX cards in Garmin navigators.