Why is there no basemap (roads, place names, imagery) behind the shapes?

A basemap requires fetching map tile images from a third-party server on every pan or zoom. This tool makes no network requests, so it draws only your GeoJSON's own geometry, fit to its own bounding box, on a plain background with a light graticule border for orientation.

What GeoJSON shapes does this render?

Point, LineString, Polygon, MultiPoint, MultiLineString, and MultiPolygon, whether they arrive inside a FeatureCollection, as a bare Feature, or as a raw geometry object. All three shapes are wrapped into a FeatureCollection automatically before rendering. Anything else is skipped rather than causing an error.

How is the geometry positioned in the preview, is it a real map projection?

No. It's a linear fit: the data's overall longitude/latitude bounding box is stretched to fill the SVG viewBox, with latitude flipped since SVG's y-axis grows downward while latitude grows upward. That keeps shapes correctly positioned relative to each other, but it isn't a true map projection.

Can I paste just a single geometry, not a full FeatureCollection?

Yes. A bare Feature or even a raw geometry object (like a standalone Polygon) is automatically wrapped into a one-feature FeatureCollection before rendering, so you don't need to construct the full GeoJSON envelope yourself.

GeoJSON Viewer - Preview GeoJSON Geometry as SVG

Overview

Introduction

Sometimes you just want to see what a piece of GeoJSON looks like, without converting it, validating it, or pasting it into a full mapping application.

GeoJSON Viewer renders pasted GeoJSON as an SVG preview of its points, lines, and polygons, along with a legend summarizing feature count and geometry types.

What Is GeoJSON Viewer?

A read-only GeoJSON geometry previewer built on this category's shared SVG-rendering helper. It fits the data's longitude/latitude bounding box to a fixed viewBox and draws lines and polygons as SVG paths, points as small circles.

Every geo tool in this category that converts to or from GeoJSON links back to this viewer as the standard way to inspect the result.

How GeoJSON Viewer Works

The pasted text is JSON.parse'd and normalized to a FeatureCollection: a FeatureCollection passes through as-is, a bare Feature or raw geometry object gets wrapped in one automatically.

That FeatureCollection is handed to the shared geoJsonToSvgPaths helper, which walks every coordinate to find the overall bounding box, then linearly projects each geometry into SVG path/point coordinates ready to render directly.

When To Use GeoJSON Viewer

Use this whenever you have GeoJSON, from an API response, a converted KML/GPX/shapefile, or hand-written test data, and want to quickly confirm it looks like what you expect.

It's especially useful right after using any of this category's converters, as the last sanity check before trusting the converted output.

Often used alongside KML to GeoJSON Converter, GPX to GeoJSON Converter and Shapefile Viewer.

Features

Advantages

Runs entirely client-side. Your GeoJSON never leaves your browser, and no map tiles are fetched.
Accepts FeatureCollections, bare Features, and raw geometry objects without requiring manual wrapping.
A feature-count and geometry-type legend gives a summary alongside the visual preview.

Limitations

No panning, zooming, or interactivity. It's a static preview fit to the data's bounding box.
No basemap imagery: no roads, place names, or terrain are drawn.
GeometryCollection members and any unrecognized geometry types are skipped rather than rendered.

Examples

A FeatureCollection with two points and a line

Input

{"type":"FeatureCollection","features":[{"type":"Feature","geometry":{"type":"Point","coordinates":[-122.4,37.8]}},{"type":"Feature","geometry":{"type":"LineString","coordinates":[[-122.5,37.7],[-122.3,37.9]]}}]}

Output

An SVG preview with one small circle and one line stroke, both fit to their shared bounding box, plus a legend reading "2 features, Point, LineString"

Each feature's geometry type determines whether it's drawn as a circle (Point) or a path (LineString), and both share the same bounding-box projection so their relative positions stay correct.

Best Practices & Notes

Best Practices

Use this right after any conversion (KML, GPX, or shapefile to GeoJSON) as a quick visual sanity check before trusting the output.
Check the legend's geometry-type list if the preview looks emptier than expected. An unsupported geometry type may be present in your data.
Paste a bare geometry object directly when you just want to check one shape, no need to wrap it in a Feature or FeatureCollection yourself.

Developer Notes

`parseGeoJsonForViewer` in `geojson-viewer.ts` normalizes three possible top-level GeoJSON shapes (FeatureCollection, Feature, or a raw Geometry) into a single FeatureCollection. The component then calls the shared `geoJsonToSvgPaths` from `geo-svg-render.ts`, which keeps the projection math shape-agnostic and reusable by `shapefile-viewer.ts`.

GeoJSON Viewer Use Cases

Sanity-checking GeoJSON right after converting it from KML, GPX, or a shapefile
Quickly previewing an API response's geometry without pasting it into a full mapping application
Visually inspecting hand-written or generated GeoJSON test data before using it elsewhere

Common Mistakes

Expecting to see roads, place names, or imagery behind the shapes. This viewer draws only the GeoJSON's own geometry; no basemap tiles are fetched.
Pasting invalid JSON, such as a trailing comma or unquoted keys, and expecting the geometry to render anyway. Valid JSON is required before parsing starts.

Tips

If the preview looks stretched, that's the bounding-box fit mapping the data's actual lon/lat extent to the viewBox regardless of aspect ratio.
Pair with Lat/Lng Point Finder if you need to manually add a reference coordinate alongside geometry you're previewing here.

GeoJSON Viewer