What is the maximum size a raster Grid can be?
The maximum size any single file ArcGIS 8.x, ArcInfo Workstation and ArcView 3.x can address is 2.147 GB. This is a limit of 32 bit application software, and is independent of the capabilities of the operating system - even if using a 64 bit OS, for example. The absolute number is 2**31 - 1 bytes (2147483647).
No single file in the grid folder, such as w001001.adf or w001001x.adf, can exceed this size; however the total size of the folder can.
Floating point grids generally require more space than Integer grids.
Grids with a spatially variegated distribution of values; for example, minimal contiguous areas of equal cell values, require more disk space than uniform grids. The grid format uses a run length encoding scheme, whose effectiveness is reduced when there is a high degree of variation in adjacent cell values.
Sample grid sizes:
- 100,000 x 100,000 cells of a constant integer value is about 110 MB
- 100,000 x 100,000 cells of alternating integer cell values of 0 and 1 is about 1.4 GB.
- 23,000 x 23,000 cells of random floating point numbers from 0 to 1 is about 2.12 GB.
If this limit is encountered, there are several possible solutions:
- process the data in sections.
- reduce the resolution of the data.
- convert the data to integer, if it is acceptable to do so.
This issue is resolved in ArcGIS 9.x. With this release there is essentially no limit on the size of an ESRI grid that can be used within ArcGIS Desktop. This has been accomplished supporting the "tiling" the ESRI grids internally, so that each component remains below the 2.1GB limit. ArcGIS 8.x, ArcInfo Workstation and ArcView 3.x do not support this new grid format.