Formats
Eight file formats, read directly
Which format for which job
The honest summary of a comparison that usually gets reduced to “use GeoJSON”.
| Format | Carries | Loses | Best for |
|---|---|---|---|
| CSV | Points, lines or polygons from coordinate or geometry columns | Everything structural: no types, no projection, no geometry | Exports from a database or dashboard |
| Excel | Points, lines or polygons from coordinate or geometry columns | Formulas are read as values; merged cells break the table | Data that lives in a spreadsheet already |
| KML | Points, lines, polygons, folders, styling | Network links and time animation are not geometry | Anything drawn in Google Earth |
| KMZ | The same as KML, compressed with its images | Custom raster icons are replaced with vector markers | Sending a KML with images attached |
| GPX | Lines and points, with elevation and timestamps | No polygons, no attributes beyond the GPX vocabulary | Recorded tracks from a device |
| GeoJSON | Points, lines, polygons, mixed, arbitrary properties | Nothing, but file size grows quickly with precision | Anything web-facing; the native format here |
| TopoJSON | The same as GeoJSON, with shared arcs stored once | Not directly renderable; needs converting first | Boundary files that must stay small |
| Shapefile | One geometry type per file, with attributes | Field names past ten characters, nulls, booleans, curves | Data from a government agency or desktop GIS |
Format guides
Each guide covers what the format is, what MapCrafter reads from it, and the problems it actually causes — coordinate order in KML, field name truncation in Shapefile, byte order marks in CSV.
CSV
21 examplesTurn a CSV into a map: latitude and longitude columns, WKT geometry, or an address column that gets geocoded. Delimiter detection, BOM handling and a free tier with no card.
Read the guideExcel
4 examplesMap the first sheet of an .xlsx or .xlsm workbook using coordinates, WKT or GeoJSON geometry, or an address lookup. Legacy .xls files need conversion first.
Read the guideKML
3 examplesOpen a KML file in the browser: placemarks, paths and polygons render on ten vector basemaps, with popups, labels and styling. No Google Earth install, nothing to download.
Read the guideKMZ
1 exampleOpen a KMZ file in the browser. The archive is unzipped locally, the KML inside is parsed, and placemarks, paths and polygons render on ten vector basemaps. Nothing is uploaded.
Read the guideGPX
2 examplesOpen a GPX file in the browser: tracks, routes and waypoints render on ten vector basemaps with elevation and timestamps as popup fields. Nothing to install, nothing uploaded.
Read the guideGeoJSON
14 examplesOpen a GeoJSON FeatureCollection in the browser: points, lines and polygons on ten vector basemaps, with data-driven colour, labels and popups. No upload, free export.
Read the guideTopoJSON
267 examplesView TopoJSON in the browser. Each object is converted to a GeoJSON layer and rendered as points, lines or areas on one of ten vector basemaps.
Read the guideShapefile
2 examplesOpen a zipped Shapefile in the browser and export it as GeoJSON. The .shp geometry, .dbf attributes and .prj projection are read together, with no desktop software.
Read the guide
What every format has in common here
- Files are parsed in your browser and are not uploaded.
- Geometry is detected rather than declared, wherever it lives.
- Rows that cannot be placed are counted and reported, never dropped quietly.
- Coordinates outside the valid range are flagged, because that usually means a projected system rather than bad data.
What no format carries
- A projection, except Shapefile — everything is assumed to be WGS84.
- Column types, except in Excel and Shapefile.
- Any guarantee that a “latitude” column holds latitudes.
Format questions
- Which map file format should I use?
- GeoJSON if you are choosing, because it carries any geometry and arbitrary properties, is readable as text, and every web tool accepts it. TopoJSON when the file has shared boundaries and size matters, which for world or national boundaries is a factor of four or five. Shapefile only when a source only publishes that.
- What is the difference between KML and GeoJSON?
- Both carry points, lines and polygons with attributes. KML is XML, from Google Earth, and carries display styling and folder structure as part of the format. GeoJSON is JSON, from the web mapping world, is smaller for the same geometry, and stores properties as plain JSON with no styling attached.
- What does a Shapefile lose compared with GeoJSON?
- Attribute names are truncated to ten characters, there is no boolean or null type, no support for curves, one geometry type per file, and the projection lives in a separate .prj file that is often lost. Going GeoJSON to Shapefile and back is lossy in ways that are not obvious until you look at the columns.
- Can MapCrafter read a file that has no coordinates?
- Address-like columns are retained for an explicit geocoding step in the layer inspector. A separate region-value table is not automatically joined to built-in boundaries. Supply geometry or prepare the join before importing.
- Do I need to convert my file before importing?
- No. All eight formats are read directly, including KMZ archives and zipped Shapefile sets, which are unpacked in the browser. There is no conversion step and nothing to install.
- Which format is smallest?
- TopoJSON, typically by a factor of four or five over the equivalent GeoJSON, because shared borders are stored once and coordinates are quantised to integers. For a world boundary file that is the difference between a slow first paint and a fast one.
Bring the file you already have
Whichever of the eight it is, the geometry gets detected and a starting style gets applied. No conversion, no desktop software, no card.
Open the studio