Xdb StorageManager

Note !!! : The Xdb StorageManager is not supported at the moment, 
as .txt files in Unix format are not correctly interpreted.

non-delimited fixed-length files

Non-delimited fixed-length ASCII files can be read with the XDB storagemanager.

This StorageManager reads data from two different files, with the same file name but with different extensions:

• An .xdb file: a meta file describing the contents of the primary data .txt file.
• The .txt file: a file with the actual values (primary data).

Example:

unit<uint32> Table: StorageName = "%SourceDataDir%/ASCII/XDB.xdb"
{
   attribute<int32>   IntegerAtt;
   attribute<float32> FloatAtt;
}

Only a reference need to be configured to the .xdb file. The accompanying .txt file needs to be located in the same folder.

Writing data to non-delimited fixed length ASCII files with the XDB storage manager is not supported.

Use the gdal_vect StorageManager to read data from and write data to delimited ASCII files.

Example: XDB.xdb:

5 0
IntegerAtt 5 1
FloatAtt 7 9

The first row always contains two values separated by a space:

• The first value determines the number of rows with primary data in the .txt file and is used to determine the NrOfRows of the domain-unit used for these data values. In the example, this number is 5.
• The second value indicates the number of header lines in the .txt file. In the example, no header lines occur so this number is 0.

In the following lines all occurring attributes need to be described, each with the format: name, offset and type, separated by spaces:

• The name is the same name as used for the attribute in the GeoDMS configuration. In the example the general names IntegerAtt and FloatAtt are used.
• The offset indicates the number of positions that are used for the attribute. The start position in each line is always the first position. In the example 5 positions are used for the IntegerAtt and after that 7 positions for the FloatAtt.
• The type is used to determine the value-type of the resulting attribute. The following codes can be configured:
  • 0: uint32
  • 1: int32
  • 8: float64
  • 9: float32

In the example the codes 1 (int32) are used for the IntegerAtt and 9 (Float32) for the FloatAtt.

the .txt file

The .txt file accompanying the .xdb file looks as follows: XDB.txt:

   0        0
   1        1
 256  9999999
-100       -2.5
9999       99.9