ESRI ASCII Grid (.asc)
Open BetaESRI ASCII Grid is a text raster format with a six-line header (NCOLS, NROWS, XLLCORNER, YLLCORNER, CELLSIZE, NODATA_VALUE) and a grid of space-separated numbers. It opens in any text editor and is read by ArcGIS, QGIS, GRASS, GDAL, R, rasterio. To be honest: our export first renders OSM vector layers to an intermediate GeoTIFF, then converts it to .asc via the GDAL AAIGrid driver. So the output is a rasterized map of the area as a text grid, not an elevation/terrain model. For actual relief use HGT or an external DEM. The file is delivered as a ZIP archive: the .asc itself plus a .prj projection (CRS) file so GIS software knows the coordinate system — like a Shapefile.
주요 기능
ASCII Grid 형식 소개
ESRI ASCII Grid is the simplest of the raster formats: six header lines (the number of columns and rows, the coordinates of the lower left corner, the cell size, the NODATA value) and then a grid of numbers separated by spaces. The file reads in any text editor and is parsed by five lines of code in any language, which is why it is still used in academic pipelines and for long-term storage.
The format is chosen when what matters is not efficiency but portability and transparency: a supplement to an article, a dataset in a repository, an input grid for GRASS, R or rasterio, an exchange with a colleague who has no GIS. Everything in the file is visible to the eye — nothing is hidden in a binary structure.
The output is a ZIP archive with two files: map.asc with the grid of values and map.prj with the description of the coordinate system. It is done that way because the .asc itself does not store the projection, and without it a GIS will not put the grid in its place. The cells hold the rasterized map of the selected area — the OSM vector layers are first drawn into an intermediate GeoTIFF, from which the first band is taken; empty cells get the value -9999.
ASCII Grid 파일을 여는 프로그램
다음 프로그램과 애플리케이션으로 OSM2CDR에서 내보낸 ESRI ASCII Grid (.asc)(.asc) 파일을 열고 편집하고 작업할 수 있습니다:
Format specifications
- Open standard
- 2D only
- Lossless (no quality loss)
- No attributes
- Output: 1 file
- Plain-text AAIGrid: a six-line header plus a grid of cell values rasterized from the OSM vector layers via an intermediate GeoTIFF, NODATA -9999.
ASCII Grid 지도 사용자
ASCII Grid 내보내기 방법
내보낸 뒤 여는 방법
- Unpack the archive — keep map.asc and map.prj in the same folder and with the same name, otherwise the GIS will not find the coordinate system.
- QGIS — Layer → Add Raster Layer → pick the .asc; the grid lands in its place, because the extent and the cell size are written in the header.
- GDAL — gdalinfo map.asc shows the header and the extent, and gdal_translate converts the grid into GeoTIFF if you need a compact binary version.
- R and Python — terra::rast() or rasterio.open() read the format directly; if you like, the grid can be loaded with plain numpy, skipping the six header lines.
- A text editor — Notepad++ or any other will open the file to check the header; for large areas pick an editor that handles big files.
ASCII Grid 형식의 인기 지도
ESRI ASCII Grid (.asc) 지도 내보내기 받기
OpenStreetMap에서 전문가용 ASCII Grid 지도를 다운로드하세요. 즉시 생성, 모든 영역 지원.