Turn an ESRI ASCII Grid (.asc) into a table with cell-center x/y coordinates, each raster value, and its row and column. Convert and download locally in your browser.
Choose an ESRI ASCII Grid file to preview its contents.
Leave output blank to keep the grid’s native coordinates. Reprojection needs the source CRS, which can come from a matching .prj file.
For an EPSG code not already available in your browser, only the code is looked up from epsg.io. Your grid data stays on your device. Custom WKT or PROJ definitions work without a lookup.
| x | y | value | row | column |
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An ESRI ASCII Grid stores raster data as a plain-text header followed by rows of cell values. The header describes the number of columns and rows, the lower-left grid origin, and the cell size. This free online ESRI ASCII Grid to CSV converter reads that structure and writes each cell as a record in a downloadable comma-separated file. Use the CSV in a spreadsheet, a database, a script, or another data workflow that works with tabular rows.
Every output record includes x, y, and value, plus one-based row and column fields so you can trace a record back to its position in the raster. The coordinates refer to the center of each cell. Rows in an ASCII Grid are stored from top to bottom; the converter accounts for that ordering when it calculates each y coordinate. The first data row therefore maps to the northernmost row of the grid.
The format allows an origin written as xllcorner and yllcorner, or as xllcenter and yllcenter. When the header gives a corner, the center of the first cell is half a cell size east and north of that origin. When the header gives a center, that coordinate is used directly. The cell size is added for each step across or down the grid. By default, the output uses the same coordinate system and units as the input file; set an output CRS to transform coordinates.
An ASCII Grid header does not include enough information to identify its map projection. Add a matching .prj sidecar, enter the source EPSG code, or paste a WKT or PROJ definition before choosing a different output coordinate system. You can reproject to WGS 84 longitude and latitude or Web Mercator with one click, or enter another EPSG code. For EPSG definitions not built into the converter, only the code is retrieved from epsg.io; raster content remains local.
If your grid declares a NODATA_value, those cells are included in the CSV by default, preserving the complete grid. Clear the NoData option to omit them when you only need cells that contain data. If the header does not declare a NoData value, every grid value is exported. The converter also checks that the header dimensions match the values in the file and reports an error when the input is incomplete or malformed.
Select multiple .asc files at once or choose a ZIP archive containing grids. For each grid, the converter creates a separate CSV and packages batch results into one ZIP download. Include matching .prj files to provide source CRS information. Use the preview selector to inspect each raster’s cell pattern and coordinate extent. The preview is rendered locally without map tiles, so file contents and coordinates are not sent to a basemap provider.
The converter supports up to 200 MB of combined input and 1,000,000 cells per batch. Large grids depend on the memory available to your browser and device. Your selected grid files are processed in the browser; only an EPSG code may be sent to epsg.io to retrieve an otherwise unavailable projection definition.
It creates one CSV record per grid cell with the cell-center x and y coordinates, the cell value, and one-based row and column numbers. Coordinates stay in the grid’s native coordinate system and units.
It can when you provide the source coordinate reference system. Add a matching .prj file or enter a source EPSG code, then choose WGS 84 (EPSG:4326) as the output CRS. The ASCII Grid header alone does not identify its projection.
The converter reports the center of each cell. It reads xllcorner and yllcorner origins by adding half a cell size, or uses xllcenter and yllcenter origins directly. Rows in an ASCII grid run from the top down, so y coordinates decrease by one cell size per row. If you select another output CRS, these coordinates are transformed after calculation.
NoData cells are included by default using the value declared by NODATA_value. You can clear the Include NoData cells option to leave those records out of the CSV.
No. The file is read and converted in your browser. Its contents are not sent to BFOTKit by this converter.
The converter accepts up to 200 MB of combined input and 1,000,000 cells across a batch. Processing large grids also depends on available memory in your browser and device.
Yes. Select multiple .asc files or choose a ZIP containing multiple grids. The converter creates one CSV per grid and packages batch results into a ZIP download. Matching .prj files can be included alongside the grids.
Yes. Provide the source CRS as an EPSG code or matching .prj file, then choose an output EPSG code or enter a WKT or PROJ definition. EPSG definitions not built into the browser library are looked up by code from epsg.io; grid contents are not sent.
No. The preview draws the raster cells and coordinate extent in your browser without contacting a map tile service. It shows the grid layout, not street names or satellite imagery.
If you have an ESRI ASCII Grid (.asc), convert it to CSV with this tool, download the CSV, then open it in Excel or use Excel’s Data > From Text/CSV import option. The converter exports cell coordinates, values, rows, and columns. Plain ASCII text needs to be structured into columns before it can be imported as a useful spreadsheet.
Choose your ESRI ASCII Grid (.asc) file in the ASC to CSV converter. It reads the grid header and values, previews the raster, and creates a CSV row for each cell with its x and y coordinates, value, row, and column. Download one CSV or batch results as a ZIP.
CSV is a table format, so the text must have a consistent structure, such as fields separated by commas or tabs and records separated by new lines. This converter is designed for ESRI ASCII Grid (.asc) raster files; it does not convert arbitrary unstructured text into a table.
No. ASCII is a character encoding that represents text using numeric codes, while CSV is a plain-text format for storing rows and columns of values. A CSV file can contain ASCII characters, and an ESRI ASCII Grid uses text to store raster data, but the terms describe different things.
ASCII code conversion means translating numeric character codes into text characters, or encoding characters as numbers. That is different from converting an ESRI ASCII Grid (.asc) into CSV. This page converts raster grid cells into coordinate and value records; it does not translate character codes.
Open the ASC to CSV tool, select or drop a valid ESRI ASCII Grid (.asc) file, check the cell preview, and select Download CSV. Each output record contains the cell-center coordinates, raster value, and row and column indexes. The conversion runs in your browser.
Select the .asc file in the online converter. The tool checks the ESRI ASCII Grid header, converts each cell into a CSV record, and lets you preview the result before downloading. Add a matching .prj file or enter a source CRS if you also need to reproject coordinates.