Dinamica EGO delegates reading and writing most map formats to the GDAL library. This allows Dinamica EGO to handle several previously unsupported file formats.
Thanks to GDAL, Dinamica EGO can read maps in the file formats listed below1).
Thanks to GDAL, Dinamica EGO can write maps in the file formats listed below2).
Dinamica EGO uses the file extension to decide the map format used to write the file. However, some formats do not either impose or suggest an extension to represent the supported formats. To workaround this limitation, Dinamica EGO invents a corresponding extension using the file format description. On the list of formats below, file formats marked with a star (*) have extensions invented by Dinamica.
The support to Arc/Info ASCII Grid (.asc) in GDAL is read only. So, Dinamica EGO provides the writing capability itself. This format can read images using cell types “Signed 32 Bit Integer” and “IEEE 754 32 Bit Real”. All cell types can be written, but they are automatically converted back to one of those formats next time Dinamica EGO reads the image again.
The current ERMapper (.ers) support in GDAL ignores class names. To workaround this limitation, support to reading and writing this file format is provided by Dinamica EGO itself.
The GDAL implementation (and some times the underlying file format) imposes limitations to the representation of projections, layer names, category names and their corresponding colors. Some of these limitations and their corresponding workarounds are listed in the table below:
| Limitation | Workaround |
|---|---|
| Some file formats do not support storing projections. | Use a VRT file or an auxiliary PAM XML file to keep this information. |
| Several file formats do not support storing category names. | Use a VRT file or an auxiliary PAM XML file to keep this information. The ERMapper file format has the best support to category names and colors. |
| Several file formats do not support storing category colors. | Use a VRT file or an auxiliary PAM XML file to keep this information. The ERMapper file format has the best support to category names and colors. |
| Several file formats do not support the storage of layer names. | Use a VRT file or an auxiliary PAM XML file to keep this information. The ERMapper file format also has support to layer names. |
| The categories must start from 0 and their definition must be contiguous. | Unfortunately, the only way to workaround this limitation is defining dummy categories (Dinamica EGO does this when representing non-contiguous categories in a GDAL supported format) or using the ERMapper file format. |
| Some formats do not preserve category colors when a specified number of bits per sample is used. | Unfortunately, the only way to workaround this limitation is using a different format or choosing a number of bits per sample that does not have this limitation for a given format. For example, Geotiff format only stores category colors when the cell type is 8 bits unsigned. |
| Categories represented by negative values are not supported. | Unfortunately, there is no way to workaround this limitation, except by avoiding the use of negative categories. |
The ERMapper file format is handled by Dinamica EGO itself and not delegated to the GDAL library. For that reason, the PAM XML file can not be used with this format.
Dinamica EGO only retrieves and uses category names and colors from the first layer/band when reading a GDAL supported format. All the other layers/bands are supposed to use the same category names and colors.
It is important to observe some additional details concerning how map reading behaves in the current Dinamica EGO version:
When the map projection is not found, the map projection is left undefined. Previous Dinamica EGO versions (Dinamica EGO 1.8) assume a LOCAL projection in these cases.
The behavior concerning the omission of cell resolution is also different in the current version. So, when the cell dimension is not defined, a one-meter resolution (or one degree, depending on the map projection used) is assumed. Previously, Dinamica would assume a 100 meter or a one degree resolution, depending on the map projection used.
It is only possible to load maps represented by 8, 16, 32 or 64 bits per cell. Other cell types are not supported.
And an additional note concerning map writing: some formats do not support natively all the informations about map projections, map registration, cell resolution, layer names, category names etc. To workaround this, the GDAL library automatically writes an additional PAM XML file containing all the informations that can not be stored in the map file itself. This PAM XML is automatically processed when the map is loaded again in Dinamica EGO.
Dinamica supports a virtual file format called VRT defined by GDAL.
This format can be used to transform an image defining a different registration info, different class names and a different color table. It can also be use to create mosaics from several different images.