The Coordinate System parameter for the Microsoft Excel reader should be set if:

• A. All of the above
• B. The data will be viewed with a background map
• C. The writer format requires a coordinate system
• D. The data will be compared to other data in a different coordinate system

Answer: (A)

Setting the Coordinate System for the Excel reader is necessary whenever the numbers in Excel represent spatial locations and you plan to view, reproject, or compare them. If you’re going to view the data against a background map, the map uses a specific coordinate reference system and the data must be assigned a CRS so it lines up correctly with that map. Some writer formats also require a coordinate system to be defined so they can export the data properly. And if you’ll compare this data with other datasets that live in a different coordinate system, you need a defined input CRS to perform any accurate transformation or comparison. Because each of these scenarios relies on knowing how the coordinates are referenced on the Earth, all of the above are valid reasons to set the Coordinate System for the Excel reader. Without it, the coordinates could be misinterpreted or misaligned.