: Raw data from total stations used by land surveyors. These are often ASCII text files containing coordinates. System/Support Files
If the online converters fail, your file might not be a diagram. The extension is used by several different types of data: Open, Edit, and Convert SDR Files - SmartDraw convert sdr file to jpg online fixed
: Specifically lists SDR to JPG conversion. It is a browser-based tool that requires no installation. : Raw data from total stations used by land surveyors