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Introduction

The GeoDMS calculates with memoy arrays. To read data from and write data to (external) sources, StorageManagers are used. Since version 6.045 The GeoDMS includes the GDAL library as a StorageManager collection to read multiple (spatial) data formats. To write data to and for some specific read functions, a set of GeoDMS StorageManagers can be used.

If a StorageManager is configured, data is read from the storage when requested in a view or calculation. Data is written to the storage when a data item is update (results of the expression are calculated). Requesting data in a view triggers the GeoDMS to update items, as well as the submenu items Update Treeitem and Update Subtree in the GeoDMSGUI.

A StorageManager is configured by setting properties to a data item or it's parent item.

It is advised to configure source data items in one source data container, these data items can be referred to from any other location in the configuration.

Data can also be explicitly exported with the GeoDMSGUI to Ascii Grid, Bitmap/Tiff of Ascii Table or Shape File format with the File > Export Primary Data menu options.

Since version 5.49 The GeoDMS uses a CalcCache to store intermediate results for performance issues and to calculate with large datasets. More information on this CalcCache can be found in the CalcCache Guide.

Vector, Grid and non spatial data

For spatial data a distinction is made in:

  1. Vector data: point, arc or polygon geometriy data for one-dimensional domain units
  2. Grid data: attributes for two-dimensional domain units

In GDAL this same dinstinction is used, The gdal.vect StorageManager is used to read vector data, gdal.grid for grid data.

Non spatial data can be also partly be read with the gdal.vect StorageManager, but also by some other StorageManagers.


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