Sometimes, it is necessary to convert raster file types. The process that's required to convert the data may need to be run through a number of times so that you can produce the best quality image. There are two options to do this: using the Translate tool or Exporting Raster.
About converting raster files
Translating
In the following example, we have taken an OpenData aerial photograph from the UK Environment Agency, which is located in the aerial folder in the samples. It has been processed twice to demonstrate why it might be necessary to experiment with settings. As you can see in the following screenshot, converting the data from ECW to TIFF has degraded the image and, in both instances, increased the file size of...