Esri ASCII Grid Reader/Writer

FME Format Type Identifier	ESRIASCIIGRID
Reader/Writer	Both
Typical File Extensions	.grd, .asc

FME can read and write data in the Esri ASCII Grid format.

Esri ASCII Grid files are raster files containing elevation data, and each elevation sample in the file is a point in a single FME raster feature.

Esri ASCII Grid is a very simple format. It has a very short header that precedes the raster data. This header provides the location and size of the raster to follow.

Note As a text-based format, this format will usually not perform as well as binary raster formats (for example, GeoTIFF) for reading and writing. If performance is important, consider using another format.

Esri ASCII Grid Product and System Requirements

Format	FME Platform			Operating System
Reader/Writer	FME Form	FME Flow	FME Flow Hosted	Windows 64-bit	Linux	Mac
Reader	Yes	Yes	Yes	Yes	Yes	Yes
Writer	Yes	Yes	Yes	Yes	Yes	Yes

Reader Overview

FME considers a single Esri ASCII Grid file to be a dataset.

Writer Overview

The Esri ASCII Grid writer creates and writes data into a single folder specified by the Dataset parameter.

FME Raster Features

FME raster features represent raster data and use several concepts that are unlike those used in the handling of vector data.

For comprehensive information about how FME processes raster data, see Rasters.

Esri ASCII Grid only supports rasters with a single numeric band.

The raster is written as a series of rows, which contain one ASCII integer or floating point value per column in the raster. The first element of the raster corresponds to the upper left-hand corner of the raster.

For each raster, there is only a single feature returned, since this feature will contain the entire raster.