Batch Coordinate Converter (Excel, CSV)

When you need batch coordinate conversion

Survey offices and municipal planning departments rarely receive coordinates one at a time. They arrive as lists: an old ED50 stake-out table, hundreds of points collected in the field with GNSS, corner points in a tender package, or an Excel sheet from another agency. Converting such lists point by point is slow and invites copy-and-paste mistakes. This tool converts every row of a file with the same rules, flags the rows it cannot read, and lets you check the result both as a table and on a map.

How to use it

1. Choose a CSV, TXT, NCN or Excel (.xlsx, .xls) file, or paste cells copied from a spreadsheet into the text box. The delimiter (semicolon, comma, tab, space) and the header row are detected automatically, and you can override both.
2. Select the columns holding the easting and northing values, plus the point name and height columns if you have them.
3. Choose the source and target coordinate systems. For geographic input where you do not know the target zone, Suggest zone picks the nearest zone from the median longitude of the data.
4. Set the output format, number of decimal places and column order, then press Convert. After checking the result on the map and in the table, download it as CSV, Excel, KML, GeoJSON or DXF.

Files with tens of thousands of rows are processed in chunks; a progress bar is shown and the page stays responsive. The table shows the first 500 rows and the map the first 500 valid points, while the downloaded files contain every row.

The Y and X confusion

Turkish surveying and cadastral practice writes Y for easting and X for northing. Most GIS software and international files use X for easting and Y for northing. A column headed "X" can therefore mean a different axis depending on where the file came from. The tool labels its column selectors Easting and Northing rather than relying on headers, and it checks the values. In TM and UTM zones the easting is around 500,000 with 6 digits, while the northing in Turkey lies between 3.9 and 4.7 million with 7 digits. If the choice looks reversed a warning appears, and Swap axes exchanges the two columns. For geographic coordinates the east axis is longitude and the north axis is latitude.

Supported systems

• TUREF (ITRF96) 3° TM: EPSG:5253-5259 with central meridians 27, 30, 33, 36, 39, 42 and 45. This is the system used for large-scale mapping in Turkey.
• WGS84 geographic and UTM: EPSG:4326 and zones 35N-38N (EPSG:32635-32638). Geographic input may be decimal degrees or DMS (for example 39°55'15"N or 39 55 15.2); output can be DD or DMS.
• ETRS89 / UTM: zones 28N-31N (EPSG:25828-25831) for data from Spain and Portugal. No parameters are applied between ETRS89 and WGS84; because ETRS89 is fixed to the Eurasian plate, the two now differ by up to about a metre.
• ED50: geographic (EPSG:4230), 6° UTM zones 28N-38N (EPSG:23028-23038) and 3° TM (EPSG:2319-2325).
• Web Mercator (EPSG:3857) and the other EPSG definitions in the site's coordinate system list.

Accuracy limits

ITRF96 and WGS84: The two systems practically coincide and the tool applies no parameters between them. TUREF coordinates, however, are defined in the ITRF96 frame at epoch 2005.0, whereas current GNSS and WGS84 positions reflect the time of observation. Crustal motion in Turkey is on the order of centimetres per year, so the motion accumulated since 2005.0 can produce a difference between the centimetre and decimetre level depending on location and observation date. This is negligible for most mapping and GIS work, but not for geodetic networks and control points.

ED50: For conversions involving ED50 the tool picks the regional transformation from the EPSG registry according to the median position of the points: EPSG:1784 (ED50 to WGS 84 (30), about 2 m) for Turkey, EPSG:1633 for mainland Spain, EPSG:1635 for northwest Spain and EPSG:1631 for the Balearic Islands (about 1.5 m), EPSG:1989 for mainland Portugal (about 1 m), and the European mean EPSG:1133 (about 10 m) elsewhere. If the position cannot be determined, the default follows the page language (on this page, the European mean EPSG:1133). You can also choose the transformation manually; the one used and its EPSG code appear in the result message. A transformation with the three-parameter values (-87, -98, -121) differs from the EPSG:1784 result by roughly 8 to 10 metres across Turkey. Turkey's Large Scale Map and Map Information Production Regulation requires the ED50 to TUREF transformation to be computed from common points in the project area, or, where suitable common points are lacking, from the transformation file provided by the General Directorate of Mapping.

Official work: For cadastre, stake-out, subdivision and zoning work, the transformation parameters and methods published by the Land Registry and Cadastre (TKGM) and the General Directorate of Mapping (HGM) take precedence. This tool suits preparation, data checking and GIS import; it does not replace an official stake-out computation. Heights are passed through unchanged; no conversion between ellipsoidal and orthometric heights is made.

Data and method

Coordinates are transformed with proj4js 2.9.0 (MIT licence) using definitions from the EPSG registry. Excel files are read and written with SheetJS 0.18.5 (Apache-2.0 licence). Basemaps of the preview map come from Esri and OpenStreetMap contributors. Icons come from Lucide (ISC licence). Text parsing, DMS reading, and KML and DXF writing (AutoCAD 2000 format, POINT and TEXT entities) are this page's own code. Open-source libraries used and their licences: Data Sources.

If you need a recurring, large-scale conversion of CAD drawings and point lists into a GIS database, you can get in touch with the Rodosto team; more about the company is on the Rodosto Teknoloji website.