CSV & Data Analyzer
Data & analysis Local only
GeoJSON Viewer & Coordinate Converter
Local onlyView, draw, validate, simplify, convert, and export geographic data without map tracking.
Features3
Vertices9
Line / perimeter3613.3 km
Polygon area337425.2 km²
Select a feature to inspect it
BBOX · 112.0000, 22.0000, 121.4737, 39.9042
How to use it
- 01
Import geographic data
Open GeoJSON, CSV coordinates, KML, or GPX locally and inspect every feature on the built-in vector map.
- 02
Edit and validate
Draw points, lines, and polygons, edit names, review bounds and geometry diagnostics, or update canonical GeoJSON source.
- 03
Transform and export
Simplify vertices, convert WGS84 and EPSG:3857 coordinates, and download interoperable GeoJSON, KML, or CSV.
Frequently asked questions
Are map tiles or coordinates sent to a provider?
No. The lightweight Natural Earth basemap is bundled with the site and every dataset operation runs in your browser.
Which CSV columns are recognized?
Use longitude/lon/lng/x and latitude/lat/y column names. Other columns become feature properties.
What coordinate order does GeoJSON use?
RFC 7946 positions use longitude then latitude in WGS84 decimal degrees. The validator reports values outside those geographic ranges.
Can simplification change geometry?
Yes. Douglas–Peucker simplification removes vertices using the selected degree tolerance. Keep an original copy when topology or survey precision matters.
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