Preliminary preparation of the classifier |
Presetting of the classifier will allow to reduce time of customizing the project and manual refinement of the loaded data.
Presetting of the classifier consists in: - Assignment to the existing semantics (or addition of new semantics) of the character keys corresponding to the names of fields of loaded tables DBF; - customizing series of objects by semantics, which correspond to the fields of loaded tables.
If the classifier contains semantics which character key coincides with the field name of the loaded table - conformity is installed automatically. In one shp-file the objects of one type, as a rule, are contained. However happens and so that the file contains objects of one class, and the final type (code) of the loaded object depends on value of any attributive characteristic. For example, the file highway-line of OpenStreetMap data contains objects of road network. And the concrete characteristic of the object type of a road network is contained in the field HIGHWAY and can accept values: сonstruction, footway, living_street, path, pedestrian, etc.
In this connection there are two variants of loading: 1 - to load all by one type, and, further sequentially to mark objects in accordance with value of semantics and to perform their recoding; 2 - to create in the classifier the semantics with symbolical key HIGHWAY, to form for it the classifier of values in accordance with the list of prospective values and to create object - a series on the basis of this semantics.
In this case at customizing the project for the given dataset it is possible to specify any object from the series, and during loading after assignment to object of the corresponding value of semantics it automatically will be re-encoded.
It is recommended to not fill manually the list of values for the classifier, and to form it as follows: 1. To open corresponding file DBF by means of Microsoft Excel. 2. Simultaneously to start the classifier editor. 3. To open Notepad or other text editor. 4. To form new semantics (or to choose the most suitable existing one). 5. To copy from MS Excel the name of the corresponding field and to insert it into the "Key" field of the semantics description. 6. To execute sorting the table by the appropriate column (Data - Sorting - ….). 7. To mark the appropriate column. 8. To execute a filtration of the column contents: Data-Filters-Advanced Filter-Only unique records. 9. To copy the resulting list of values (without header), to insert it into Notepad, to number lines and to save in a text file. 10. To execute import of the list (at import to specify as the delimiter a space or at editing the list in the Notepad after numbers of lines to put «;»). |