How to create a QGIS map of unprojected data?

Question

I am attempting to display data generated by Ubisense technology. The data contains non-geographic x y coordinates. I would like to load this data into a QGIS project to perform analysis. Is it possible to load and analyze unprojected data into a QGIS project with no CRS? I have found some solutions to doing this with Leaflet but need to employ some QGIS tools to fully explore the data.

Answer 1

QGIS relies upon the EPSG database, and since EPSG is a list of Earth-based CRSes, I don't think QGIS gives you a way to load your data in a "non-geographic" CRS.

Since the data you are using is indoor location data, hopefully the coordinates are measured in something like meters or feet. If it is, you can choose any planar projection that uses the correct units. You could, for example, pick any UTM grid, such as WGS 84 / UTM Zone 1N (EPSG:32601), for data measured in meters. For data measured in feet, you would have to pick a grid system from a country (like the United States) that still uses feet.

Regarding your concern that "there will be distortion to some degree if I don't try to analyze the data on a strictly 'flat' x y grid," this is not an issue. For the most part, the GIS just operates on the coordinates in a Cartesian plane, using the Pythagorean Theorem for distance measurement. If you wanted to compute Great Circle distance (shortest distance on a sphere), you would have to use specialized functions.

Note that you should not load your data in a lat-long system (like WGS 84), because many GISes (like QGIS) will automatically convert distance and areal measurements from decimal degrees to meters. If your data are already in meters, an unnecessary conversion would be performed and the answers wouldn't make much sense.

Answer 2

The data contains non-geographic x y coordinates

If you can convert your data to a CSV or TXT file, you should give a try to Layer > Add Delimited Text Layer in QGIS. You can find an example here.

When you will be asked to define the CRS, I suggest that you use WGS84 (QGIS use it by default).