How Shapefile works
A single "shapefile" is really a bundle: the mandatory .shp (feature geometry), .shx (a shape index for fast seeking), and .dbf (a dBASE table of attributes), usually alongside a .prj (coordinate system) and sometimes a .cpg (attribute encoding). It is the lingua franca of desktop GIS and is read by virtually every tool, from ArcGIS and QGIS to GDAL/OGR. Its age shows in several hard limits: DBF attribute field names are truncated to 10 characters, each file component is capped at 2 GB, every file holds a single geometry type, and attribute types are constrained to what DBF supports (limited-width text, numbers, dates, and booleans). For predictable, fail-closed imports, GeoConvert accepts inline dBASE III (0x03) C/N/F/L/D fields; newer dBASE/VFP variants and memo or binary fields are rejected.
What are .shp, .shx, .dbf and .prj files?
A Shapefile is a set of sibling files with the same base name. For GeoConvert input, .shp and .shx are required; .dbf is optional for geometry-only conversion, with a warning that attributes may be unavailable. Include .dbf for a complete dataset with attributes, and .prj/.qpj and .cpg to avoid CRS and encoding ambiguity.
| File extension | Status | Purpose |
|---|---|---|
| .shp | Required | Stores feature geometry: points, lines or polygons. |
| .shx | Required | Indexes geometry records so software can locate features efficiently. |
| .dbf | Recommended | Stores attributes, one record per feature. Required for complete attribute delivery; optional for GeoConvert geometry-only input, which warns when it is absent. |
| .prj | Recommended | Describes the coordinate reference system as WKT so the layer is positioned correctly. |
| .cpg | Recommended | Declares the character encoding used by text fields in the .dbf table. |
If a Shapefile will not open, first confirm that .shp, .shx and .dbf share exactly the same base name and remain in one folder. If the layer opens in the wrong place, recover the correct .prj or identify and assign the source CRS before reprojecting—do not guess WGS 84.
Recovery workflow
Missing .shx geometry index
Action: Ask for a complete export first. A desktop GDAL workflow can attempt to rebuild the index from an intact .shp with SHAPE_RESTORE_SHX=YES. GeoConvert requires the index and does not repair it.
Check the result: Open the repaired set, compare the feature count and extent with a trusted source, and keep the original files.
Missing .dbf attributes
Action: Recover the matching DBF from the sender or a backup. Geometry cannot reconstruct lost attribute values. A geometry-only desktop recovery is not a complete restoration of the dataset.
Check the result: Check record alignment and known identifiers after recovery; do not pair a DBF from a different export.
Missing .prj or wrong location
Action: Obtain the original CRS definition or identify it from authoritative survey/provider metadata. Assign that source CRS to the existing coordinates, then reproject if required.
Check the result: Check several known control points and verify the layer CRS, rather than relying only on the project CRS.
Missing .cpg or garbled text
Action: Recover the encoding declaration or obtain the DBF encoding from its author. In desktop GIS, explicitly choose the confirmed encoding before exporting a UTF-8-compatible copy.
Check the result: Compare accented and non-ASCII strings with the source. Changing the encoding label cannot recover already corrupted bytes.
Mismatched names or split files
Action: Keep roads.shp, roads.shx, roads.dbf and the related sidecars together. Recover the correct matching export; renaming unrelated components to the same base name is not a repair.
Check the result: Compare feature/record counts, known identifiers and geometry. Zip the complete matching set for delivery.
Coordinate systems and reprojection
The coordinate reference system lives in the optional .prj sidecar as a WKT (well-known text) string. When the .prj is absent the CRS is genuinely unknown and consumers typically fall back to assuming WGS84, which can silently misplace data that was in another projection.
Compare Shapefile with other GIS formats
Convert Shapefile to another format
Choose a conversion below for the online converter, format-specific caveats, and step-by-step instructions for Shapefile.
Convert files to Shapefile
Tutorials
Format standards and references
These primary sources document the file formats. GeoConvert supports the conversion features and limits described above.
Frequently asked questions
- Can I open a Shapefile with only the .shp file?
- GeoConvert requires matching .shp and .shx files, so .shp alone is insufficient. It allows missing .dbf with a warning that attributes may be unavailable. Include the matching .dbf for a complete attribute dataset; .prj/.qpj and .cpg prevent CRS and encoding ambiguity.
- Can missing attributes be recreated from geometry?
- No. Rebuilding an index is different from recovering attribute values. Obtain the matching .dbf from the original export or a backup.
- Can GDAL rebuild a missing .shx file?
- GDAL documents SHAPE_RESTORE_SHX=YES for index restoration while opening a Shapefile. Use a copy in a desktop recovery workflow and verify the result; this is not a repair feature in GeoConvert.
- What file extension does Shapefile use?
- Shapefile uses .shp (+ .shx, .dbf, .prj).
- Does Shapefile store a coordinate system?
- The coordinate reference system lives in the optional .prj sidecar as a WKT (well-known text) string. When the .prj is absent the CRS is genuinely unknown and consumers typically fall back to assuming WGS84, which can silently misplace data that was in another projection.
- Can I convert Shapefile online?
- Yes. GeoConvert can read or write Shapefile in your browser for the conversion paths listed above, without uploading free-tier files to a server.