U.S. Department of Commerce

Format Types

When using the Data Export Wizard, there are several export formats available: Native Format (copy), Raw NetCDF, Shapefile, Well-Known Text, GeoTIFF, ESRI ASCII Grid, ESRI Binary Grid, and Gridded NetCDF.

Format List

Vector (Polygon/Point) formats (Shapefile, and Well-Known Text) preserve the native structure of the data by encoding the data as polygons (radar only), or points. The polygons represent the exact range bin with vertices in latitude/longitude NAD83 coordinates while the points represent the centroid of the grid cell in latitude/longitude NAD83 coordinates.

Raster (Gridded) formats (GeoTIFF, ESRI ASCII Grid, ESRI Binary Grid, and Gridded NetCDF) are gridded representations of the data in the latitude/longitude NAD83 coordinate system. A simple nearest-neighbor resampling technique is used to populate the output grid when the input data are not on a NAD83 latitude/longitude grid. This includes input data in projections (such as Albers, Lambert or Polar Stereographic), irregularly spaced grids (curvilinear grids) and all 'Radial' (weather radar) data.

GeoTIFF '8 bit' vs. GeoTIFF '32 bit':
The GeoTIFF '8 bit' format are scaled data values between 0 and 255 and do not contain the actual data values. The data are scaled by the min and max values in each file. These files can be useful when a simple grayscale image is desired, however, due to the scale factor changing with each file, animations or any multiple file analysis is impossible.
The GeoTIFF '32 bit' contain the actual data values. Many programs can handle this type of GeoTIFF, although ArcGIS does not seem read the min and max values in the GeoTIFF header correctly. Upon loading in ArcGIS, the image will look entirely black, with bogus min and max symbology values. An easy fix is to use a 'classified' symbology that will force ArcGIS to create a histogram and scan the entire file.

The 'Native NetCDF' format does not resample the data to the lat/lon coordinate system. The data is represented in the NetCDF format and should exactly match the input data projection, structure and values.

The 'Native Format' format will do a simple copy of the data to the output directory selected. This option can be used to easily download remote data to local disk.