Find Shapefile Projection — Free .prj Checker & Fixer Tool
Detect or fix a shapefile's projection when the .prj is missing, wrong, or corrupt. Works in your browser, no signup.
GIS Projection & CRS Guides
Practical guides to finding, verifying, and fixing coordinate reference systems — without desktop GIS.
A coordinate reference system (CRS) tells your GIS software where coordinates sit on the Earth.
When the CRS is missing, wrong, or corrupt, data lands in the wrong place — often at Null Island (0,0)
or shifted by metres. These guides cover every common format, show you how to read a .prj file,
look up an EPSG code from WKT, and fix mismatched datums like
NAD83 vs WGS84. Every guide links to the free
Projection Finder tool so you can verify the result in your browser.
By File Format
Detect and fix the CRS in specific GIS file types — Shapefile, GeoJSON, GeoTIFF, CSV, and Excel.
Fix GeoJSON Projection — Why Coordinates Show in the Ocean
GeoJSON showing at 0,0 or in the ocean? Coordinates are probably in metres, not degrees. Detect the real CRS instantly.
Find GeoTIFF Projection — Read CRS from Any Raster File
Upload a GeoTIFF and instantly read its projection. Extracts embedded GeoKeys, identifies unknown CRS, and verifies coordinates.
How to Find the Coordinate System of a CSV File (Lat/Lon vs Projected)
Identify coordinate systems in CSV files with X/Y columns. Detect whether your CSV has lat/lon (WGS84), UTM, or another projection.
How to Find the Coordinate System of an Excel File (XLSX with XY Columns)
Identify coordinate systems in Excel spreadsheets with latitude/longitude or XY columns. Import XLSX coordinates correctly into GIS.
What Is a .prj File? (And How to Read, Fix, or Create One)
A .prj file defines a Shapefile's coordinate reference system in WKT format. Learn how to open, read, fix, or generate a correct .prj file.
GeoTIFF Missing Projection — How to Find and Assign the Correct CRS
Got a GeoTIFF with no projection information? Learn why GeoTIFFs lose their CRS and how to identify and assign the correct one.
Reproject Shapefiles Online — Change CRS Without Desktop GIS
Need to reproject a Shapefile but don't have QGIS or ArcGIS? Free online tools and command-line options to change CRS.
Common Problems
Fix the error messages and symptoms that bring GIS workflows to a halt.
Fix: "The CRS of a Map Projection Could Not Be Parsed" (QGIS Error Guide)
Getting a CRS parse error in QGIS? Your .prj file has corrupt or unrecognised WKT. Step-by-step fix for QGIS and ArcGIS.
Why Is My GIS Data Showing at 0,0? (Null Island Problem)
Fix GIS data appearing at 0,0 coordinates off the coast of Africa. Diagnose whether it's null values or a projection mismatch.
How to Convert WKT to EPSG Code (Well-Known Text Lookup)
Convert Well-Known Text projection strings to EPSG codes. Extract EPSG from .prj files and WKT definitions.
Datums & Projections
Understand the concepts behind CRS — datums, projections, and how to convert between them.
NAD83 vs WGS84: The 1–2 Meter Difference Explained
Understand the difference between NAD83 and WGS84 datums. Learn when the 1-2 metre offset matters (surveying) and when it doesn't (web maps).
Projection Finder — Free CRS Detection Tool
Upload a Shapefile, GeoTIFF, GeoJSON, CSV, or Excel file and instantly detect, verify, or fix the coordinate reference system. Browser-based, no install.
Frequently Asked Questions
How do I find the projection of a GIS file?
Check for a .prj file (Shapefile) or embedded CRS metadata (GeoTIFF). If metadata is missing or wrong, analyze the coordinate values: degrees (−180 to 180) indicate a geographic CRS like WGS84, while large numbers (100,000+) indicate a projected CRS like UTM. Upload the file to Projection Finder to detect the CRS automatically and preview it on a map.
What is a .prj file?
A .prj file is a small text file that stores a Shapefile's coordinate reference system in Well-Known Text (WKT) format. It is one of the required sidecar files in a Shapefile bundle (.shp, .shx, .dbf, .prj). If the .prj is missing or contains the wrong projection, the data will render in the wrong location.
Why is my GIS data showing at 0,0?
Data appearing at 0,0 (Null Island, off the coast of Africa) usually means the CRS is missing or mismatched, so the GIS software treats coordinates as WGS84 decimal degrees. If your coordinates are actually in a projected CRS (metres), they are interpreted as tiny degree values near zero. See the Null Island guide to diagnose and assign the correct CRS.
What is the difference between NAD83 and WGS84?
NAD83 and WGS84 are both geodetic datums that are nearly identical (within 1–2 metres). The difference matters for surveying and high-precision engineering but is negligible for web maps and most GIS workflows. See the NAD83 vs WGS84 guide for when to transform and when to ignore the offset.