![]() Points and simple two-vertex lines compress more than lines or polygons with many vertices. ![]() The most important factor for feature classes is the average number of vertices per feature. ![]() The makeup of coordinates and the number of attribute fields and their contents determine the amount of compression possible. The amount of compression possible in feature classes and tables can range from a negligible amount to a ratio exceeding 4:1. Benefits of compressionĬompressed file geodatabase data takes up less disk space than decompressed data while still offering comparable display and query performance. Both tools are in the File Geodatabase toolset, in the Data Management toolbox. You can compress a geodatabase, feature dataset, stand-alone feature class, or table using the Compress File Geodatabase Data geoprocessing tool and decompress using the Uncompress File Geodatabase Data geoprocessing tool. However, if required, a compressed dataset can always be decompressed to return it to its original, read/write format. Where compressed datasets differ from decompressed data is in editing: a compressed dataset is read-only and therefore cannot be edited or modified in any way except for changing its name and modifying attribute indexes and metadata.Ĭompression is ideally suited to datasets that do not require further editing. Lossy compression is a good choice if you require maximum compression and your data is not particularly accurate, or you're not worried about maintaining the full precision of your data, for example, if you're compressing data at a scale of 1:1,000,000 or greater. Lossy compression allows for up to 20 percent better compression of file geodatabase data, but floating-point values will be changed. With lossless compression, when you compress data, no information is lost, regardless of the coordinate system or types of attribute data the feature class or table contains and all floating-point values will be preserved. There are two types of compression that can be applied to file geodatabase data: lossless and nonlossless (or lossy). You might find it provides slight performance improvements in some operations but slows slightly in others. Once compressed, display and query performance is comparable to decompressed data. To reduce storage requirements, you can compress tables and vector file geodatabase feature classes (collectively referred to as datasets in the rest of this topic) to a read-only format. Restrictions when working with compressed data.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |