SDM (Spatial Database Extension) is a spatial database engine in AvisMap GIS. SDM +5 is the SDM new upgrade, which uses new data structure and index techniques for improving vast data management ability. Its combination property is higher than the other international homogeneous software. The technique of AvisMap SDM/SDM +5 successfully replaces the other international software in many large-scale GIS applications and is becoming widely used.

AvisMap SDM/SDM +5 has the function of storing mass image into large-scale relational databases and select destructive/non-destructive compression for different needs. In image database, SDM/SDM +5 will build image pyramid to avoid plenty of mass loss in wavelet image compression. It reaches the target of mass image data organizational management and rapid browse effect independent of data volume.

The spatial database engine in AvisMap GIS 5 includes: SDM 5 for SQL Server, SDM 5 for Oracle, SDM + 5 for Sybase, etc.

Multiple Database

Multiple databases can be used in AvisMap GIS such as Oracle, SQL Server.

Vector and Raster Data

AvisMap GIS has a perfect database construction, which can store vector and raster data in the same datasource at the same time without separation.

Topology Storage

The datasource in AvisMap GIS database can store network topological relationship, which stores a network dataset into a database.

Long Transaction

AvisMap SDM 5 has long transaction processing function which can processing in a long time without any influence.

Transaction is an important function in GIS software, which includes long transaction and general transaction. General transaction is supported by DBMS, directly used in AvisMap GIS SDM +5.

However, there are some slight difference in DBMS application with GIS program such as vast processing data volume in the first edit; and long edit - for several days, months or even longer; allows others to browse correlation data during editing, which requires long transaction.

AvisMap GIS has long transaction with characteristics shown below:

After starting a long transaction, other users can only browse data before editing in lock room rather than editing situation after

locked or process editing locked data;

Long transaction can persist for several days, months or even longer without any particular processing and can be continuous any time;

Modification in long transaction is quite safe. The edited data will not be lost or damaged even though in sudden power turnoff, crash or other unforeseen, catastrophic event;

At any time, if you are not satisfied with the changes, you can undo them and recover before locked;

When you submit the modified version while completing the edit,other users will receive it immediately;

Other users only can modify in locked room after you submit or undo your modification.

Adopt Compounded Multilevel Index Technique

Optional File Buffer Memory

For different levels data, it adopts different buffer mode for improving efficient. File buffer memory stores data which has been accessed for the first time as a temporary file into local disk. The speed of the data fetch will be rapid afterwards. File buffer memory occupies more disk space.

Vector Data Destructive/Nondestructive Compression

Compression can slash data capacity and fast access speed. AvisMap SDM 5 adds destructive compress mode based on original vector nondestructive compression. This special compression model will only lose one billionth of data precision when the data size is compressed to half of the original size.

Image Compression

AvisMap SDM 5 improves image compression algorithm and increases the compression ratio by a large margin.

Sequential Data

AvisMap SDM 5 stores the whole data history for convenient tracing of data in the past, and can even playback the changes of the historical data.

Optimization Edit Operation

The optimization data editing makes the work more convenient which improves the efficiency for editing.