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VecPnt: Transformation between VEC and PNT (with and without topology)
Access this help text as a web page: VecPnt
Presentation and options
This application converts point files in VEC (ASCII) format to point files in PNT (binary and structured) format, and vice versa. It can also simplify a PNT file by grouping points that are within a certain distance.
The VEC format is partially compatible with Idrisi's VEC files, but allows integer attributes to be of type long (ie, in the range [-2147483648, 2147483647] instead of in the range [- 32768, 32767]), expresses coordinates in double precision and supports attributes of type string. All Idrisi VEC ASCII formats are compatible with VECPNT.
The PNT format is a structured format that allows explicit topological relationships between points (in this case, control of spatial uniqueness), but it can also be used without explicit topological relationships to store files in a more efficient format (manage much more fast) and with much more sophisticated properties (several attributes per entity, multiple records [multiple record] per entity, full metadata, default symbolization, etc.). Indeed, a PNT file is a binary file associated with a T.dbf file with its attributes and a T.rel file with complete metadata (field descriptors, relationships with other tables, etc.), default symbolization and other information of interest.
In options 1 and 3, given n points that are very close according to the defined tolerance, they are merged into one and as many records as different attributes are generated [thus generating what we call a multiple record]. When converting a VEC file to PNT format, the order of the points in the PNT file is not the original VEC but they are ordered first by the x coordinate and then by the y coordinate. This ordering is not inherent in the format but a particularity of the application that orders them to speed up the topological structuring if requested.
Dialog box of the application
Syntax
Syntax:
- VecPnt 1 VECFile OutPNTFile Tolerance [/DescriptorCamp] [/NomCamp] [/AJUST_ENV]
- VecPnt 2 InPNTFile VECFile Precision [/CAMP] [/TAULA] [/SI_EN_BLANC] [/AJUST_ENV] [/ATRIBUT_CONSTANT] [/ALCADA]
- VecPnt 3 InPNTFile OutPNTFile Tolerance [/MULTIREG] [/AJUST_ENV]
Options:
- 1:
Converting VEC files to PNT files.
- 2:
Converting PNT files to VEC files.
- 3:
Converting PNT files to VEC files (simplification).
Parameters:
- VECFile
(VEC file -
Input parameter): Name of the VEC type point file.
- OutPNTFile
(Output PNT file -
Output parameter): Name of the fitxer structure of punts.
- Tolerance
(Tolerance -
Input parameter): Tolerance that is defined to merge points, that is to say that given 'n' points at a distance smaller than this tolerance merge into a single point.
- InPNTFile
(Input PNT file -
Input parameter): Name of the input structured point file.
- Precision
(Precision -
Input parameter): Number of decimal places written in the coordinates of the output VEC file.
Modifiers:
/DescriptorCamp=
(Field descriptor)
Text string (in quotation marks if it has spaces) that describes the Attribut field (maximum 40 characters); by default remains empty. (Input parameter) /NomCamp=
(Field name)
Text string (maximum 10 characters) that will be used as the field name in the database to be created; per default is pren ATR_VEC_? on ? can be L, F or C depending on which attributes follow enter names, reals or text strings. (Input parameter) /CAMP=
(Database field)
Together with TAULA, indicate the field of the data base that is exported to VEC format. To learn more about the values of these parameters, follow the considerations in the general syntax document. (Input parameter) /TAULA=
(Database table)
Together with CAMP, indicate the field of the data base that is exported to VEC format. To learn more about the values of these parameters, follow the considerations in the general syntax document. (Input parameter) /SI_EN_BLANC /ATRIBUT_CONSTANT= (Attribute constant) Indicates the behavior that the export to VEC will have when it has not been attributed to the data base (blank field). You can use "CONSTANT" for a constant value, "GRAPH_ID" for the graphic identifier or "IGNORATE" for ignoring the vectors without attributes (default value). (Input parameter) /ALCADA=
(Height)
Indicates which of the possible results are written in the VEC. To learn more about the values of these parameters, follow the considerations in the general syntax document. (Input parameter) /MULTIREG
(Multirecords)
All records pertaining to the merged points are subtracted from the final data base (if the parameter is not specified, only the records pertaining to the final points are retained). (Input parameter) /AJUST_ENV (Bounding box fit) Adjust the documented envelope to the metadata to the minimum rectangle. (Input parameter)
L'Idrisi es un programari © de J.Ronald Eastman and Clark University.
Aquesta aplicació fa servir i genera fitxers versió 1.1.
