About KunYu
KunYu (坤舆) is a free, all-in-one online GIS toolbox built for GIS developers and surveyors worldwide.
The Name
KunYu (坤舆) is named after the Kunyu Wanguo Quantu (坤舆万国全图), the first complete world map in Chinese history, created in 1602 by Matteo Ricci in collaboration with Chinese scholars. Just as that map brought together geographic knowledge from East and West, KunYu brings together essential GIS tools from across the web into one unified platform.
Who Built This
KunYu was created by a GIS and AI engineer who builds geospatial applications every day. The frustration of constantly switching between epsg.io, geojson.io, mapshaper, and custom coordinate conversion scripts was the direct motivation — there had to be a better way.
This hands-on experience in production GIS workflows, including working with Chinese coordinate systems (GCJ-02 and BD-09) that most international tools don't support, shapes every feature and tool in KunYu.
Our Mission
GIS professionals and developers often need to juggle between multiple websites and scripts for different tasks: looking up EPSG codes on one site, editing GeoJSON on another, converting formats somewhere else, and running coordinate transformations in yet another tool. Each context switch breaks focus and wastes time.
KunYu consolidates coordinate conversion, EPSG search, GeoJSON editing, format conversion, spatial analysis, and 12 more tools into a single, fast, and free platform — so you can stay in flow and get work done.
Technical Foundation
KunYu is powered by well-established open-source geospatial libraries, the same ones used by professional desktop GIS software:
- Proj4js — the JavaScript port of the PROJ library, providing coordinate transformation for 6,000+ coordinate reference systems from the EPSG Registry
- Turf.js — advanced geospatial analysis including buffering, simplification, boolean operations, and measurement
- MapLibre GL JS — high-performance, open-source map rendering with WebGL
- Format I/O — specialized parsers and writers for Shapefile, KML, GPX, CSV, GeoJSON, WKT, and WKB
Data attribution
Coordinate transformation grids are redistributed from the PROJ-data project. BeTA2007 (Germany) © AdV — free redistribution is allowed and welcome. OSTN15 (Great Britain) © Ordnance Survey — licensed under the 2-Clause BSD License.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
What Makes KunYu Different
Browser-Based Processing
All data processing happens in your browser using WebAssembly and JavaScript. Your files never leave your device — no uploads, no server-side processing, no account required.
18 Professional Tools
From coordinate conversion and EPSG search to GeoJSON editing, format conversion, spatial analysis, geocoding, and more — covering the full spectrum of everyday GIS tasks.
Chinese Coordinate System Support
Native support for GCJ-02 (Mars Coordinates) and BD-09 (Baidu Coordinates) transformations, a critical feature for anyone working with Chinese geospatial data that most international tools lack.
Open Standards
KunYu is built entirely on open standards and specifications: RFC 7946 for GeoJSON, the EPSG Geodetic Parameter Registry maintained by IOGP, OGC standards for WKT and WKB, and open data formats including KML (OGC), GPX, Shapefile, and CSV. There is no vendor lock-in — your data stays in standard, interoperable formats compatible with QGIS, ArcGIS, Google Earth, and every major GIS platform.
Contact Us
Have feedback, feature requests, or found a bug? Reach out to us at kunyu926@hotmail.com