Esri ASCII Grid Reader/Writer

Licensing options for this format begin with FME Desktop Professional Edition.

The Esri® ASCII Grid Reader/Writer allows FME to read and write data in the Esri ASCII Grid format.

Overview

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.

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.

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.

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. The topics below describe how FME processes raster data.

About FME Rasters Tiling and Mosaicking
Raster Properties Band Combining and Separating
Band Properties Band and Palette Selection
Palette Properties Raster Processing
Compression Raster versus Vector Features
Pyramiding Raster File Naming
Interleaving World Files
Interpretation and Data Type TAB Files
Palette Resolution  

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