IMPORT FILES
After entering the command v.import, the user will be asked which type of
file to import and create support files for:
Import to GRASS Vector Format and Creates Needed Support Files 1 - ASCII DLG file to GRASS Vector Format 2 - Binary DLG file to GRASS Vector Format 3 - ASCII DIGIT file to GRASS Vector Format 4 - Binary DIGIT file to GRASS Vector Format 5 - ASCII SCS-GEF file to GRASS Vector Format 6 - ASCII ARC/INFO file to GRASS Vector Format 7 - ASCII DXF file to GRASS Vector Format 8 - ASCII TIGER file to GRASS Vector Format
ASCII DLG File to GRASS Vector
Converts ASCII DLG files (such as those created in GRASS) to a vector file
and creates the dig_plus and dig_att support files.
The user is asked several questions:
NOTE: It should be available in the $LOCATION/dlg directory. If the DLG data has an attribute flat file, it should also be in $LOCATION/dlg.
NOTE: Some machine-processed DLG files do not make the distinction between lines and area edges. For example, in a roads map, where the desired information is line data, a downtown block surrounded by roads may be processed as an area. Because of this, the user is asked to choose whether to give precedence to areas or lines. If precedence is given to lines, the user should be aware that any lines that bound unlabeled areas in the DLG file will be stored as line data. Any unlabeled areas would therefore be lost (this is only a concern when areas are unlabeled, labeled area information will be retained). If precedence is given to areas, lines will be stored as boundaries to areas that are unlabeled.
NOTE: BE CAREFUL!!! This threshold is calculated using the scale of the original DLG or v.digit file. If the threshold is too high, excessive snapping may occur, destroying the file. In general, users seldom need to snap nodes. If snapping of nodes is desired, the user may want to run v.support separately. v.support allows the user to set the snapping threshold.
This is the name of the flat file which will accompany a DLG from a non-GRASS system. This file contains all of the DLG area numbers with a corresponding text label.
ARC/INFO DLG data is handled in a slightly different manner.
Some DLG files may or may NOT have this and processing will be required to handle each case differently.
- OR -
If the DLG does contain category codes, then the ASCII DLG file is converted to a binary DLG file.
Binary DLG File to GRASS Vector
Converts binary DLG files (which should be in the bdlg directory)
to a vector file and creates the dig_plus and dig_att support
files. The user is asked whether precedence should be given to
Areas or Lines and if nodes should be snapped to other nodes
within a calculated threshold.
This process is done in two phases:
ASCII Vector File into GRASS Vector
Converts ASCII v.digit files (which are located in dig_ascii
directory) into binary vector files and creates the dig_plus
support file. Since a vector file keeps the distinction between lines and
area edges, the user is not asked to give precedence to either. However,
the user will be asked if the user wants to snap from nodes to other nodes
within a calculated threshold.
This process is done in two phases:
Binary Vector File to GRASS Vector
Creates the dig_plus support file.
This process is done in one phase: The dig_plus support file is created by analyzing the vector file for topological information.
Acsii SCS-GEF File to GRASS Vector
Creates the dig_plus, dig_att, and dig_cats support files.
Creates a registration coordinates file.
Allows a user to create a GRASS vector file from a SCS-GEF format ASCII file.
Name of their organization. (from SCS-GEF)
Digitized Date. (from SCS-GEF)
Map Name. (from SCS-GEF)
Map Location. (from SCS-GEF)
Other Information. (from SCS-GEF)
State FIPS code.
County FIPS code.
Present GEF Coord. System (table, stplane, ll, utm).
Coord. System Desired (utm, stplane, ll, albers).
Note: scripts contains SCS macro make_1_gef. This macro makes one file out of the three (3) files found in SCS-GEF ( see SCS-GEF technical specifications for more information). The macro must be run on each data set BEFORE v.import.
ASCII ARC/INFO Ungenerate Format Files to GRASS Vector
Creates the dig_plus, dig_att, and dig_cats support files.
The program will prompt you to enter the names of ARC/INFO files to
be imported to GRASS. ARC/INFO vector files to be imported into GRASS
must be exported from ARC/INFO using the ARC/INFO Ungenerate command.
ARC/INFO vector files which are to are to be imported to GRASS,
must be either line or polygon coverages. They must also be placed
in a $LOCATION/arc directory. The section of the ARC/INFO manual
that cover the Ungenerate command describes how to export line
and polygon coverages.
A polygon coverage is represented by three files:
The program will start out by asking you which type of coverage is to be imported, as follows:
IMPORTING A POLYGON COVERAGE
The prompts that will be presented for coverage type "polygon."
COVERAGE TYPE
Enter "polygon" or "line"
Hit RETURN to cancel request
>
Answer "polygon"
NEATLINE
Do you want a neatline ?
Enter "yes" or "no"
>
If you answer yes then vectors representing
a box around the data will be inserted into
the resulting GRASS vector file, otherwise
no neatline will be created.
Next the program will prompt for the name of the lines-file
containing the arc coodinates of the polygons.
The lines-file is created with the Ungenerate LINES option
and is the same format as the map_name.pol file
created by the program. The following is the prompt:
LINES FILENAME
Enter name of the file created with the LINES
option of the ARC/INFO Ungenerate command.
Hit RETURN to cancel request
>
The next prompt for coverage type "polygon" asks for the name
of the label-points file. The label-points files is created with the
Ungenerate POINTS option and is the same format as the
mapname.lab file created by the export.vect ARC program.
The following is the prompt:
LABEL-POINTS FILENAME
Enter name of file created with the POINTS
option of the ARC/INFO Ungenerate command.
Hit RETURN if there is no such file
>
The last prompt for coverage type "polygon" asks for the name of the
label-text file. This file associates each label-point ID number
with a text string and is the same format as the mapname.txt file
created by the export.vect ARC program. The following is the prompt:
LABEL-TEXT FILENAME
Enter the name of a file that associates
label-point ID numbers with text label strings
Hit RETURN if there is no such file
>
The program will then scan the label-text file to determine how
many columns are in the file and to determine which column
should be used as the label-point ID number column.
The program will then tell you how many lines and columns are in the label-text file. Next you will be prompted to enter the number of the column to be used for GRASS category values. The category number column MUST contain only integers.
Enter the number of the column that is to be used
for GRASS category values:
and the number the column to be used for GRASS attribute text.
The attribute text column can contain a floating point number,
an integer, or a word.
Enter the number of the column that should be used
for GRASS attribute text:
Once you enter the category and attribute column numbers, the program
will begin conversion of the ARC/INFO Ungenerate files
into GRASS vector format.
IMPORTING A LINE COVERAGE
First, you are prompted for the name of the lines-file containing the arc coordinates of the lines. The lines-file is created with the Ungenerate LINES option and is the same format as the mapname.lin file created by the export.vect ARC program.
LINES FILENAME
Enter name of the file created with the lines
option of the ARC/INFO Ungenerate command.
Hit RETURN to cancel request
>
The last prompt for coverage type "line" asks for the name of the
label-text file. This file associates each line-ID number
with a text string and is the same format as the mapname.txt file
created by the export.vect ARC program.
LABEL-TEXT FILENAMES
Enter name of file associating line ID numbers
numbers with label text.
Hit RETURN if there is no such file
>
The program will scan the label-text file to determine how many columns
are in the file and will then tell you how many columns are in the
label-text. Next you will be prompted to enter the number of the column
to be used for line-ID numbers.
Enter the number of the column that is to be used
for line-ID numbers:
Next you will be prompted to enter the number of the column to be used
for GRASS category values. The category number column MUST contain
only integers.
Enter the number of the column that is to be used
for GRASS category values:
and the number of the column to be used for GRASS attribute text.
The attribute text column can contain a floating point number,
an integer, or a word.
Enter the number of the column that should be used as
for GRASS attribute text:
Once you enter the column numbers the program will begin conversion
of the ARC/INFO Ungenerate files into GRASS vector format.
DATA FILE FORMATS
Following are examples of the data files discussed in the section above.
3
711916.000000 4651803.000000
711351.875000 4651786.000000
END
3
709562.500000 4651731.000000
709617.250000 4651624.000000
709617.250000 4651567.000000
709585.000000 4651503.000000
709601.125000 4651470.000000
709696.875000 4651503.000000
709720.500000 4651574.000000
709823.750000 4651575.000000
709893.125000 4651741.000000
END
3
710296.875000 4651491.000000
710295.125000 4651470.000000
710223.000000 4651454.000000
710154.500000 4651463.000000
END
END
1 711539.875000 4651743.000000
2 711429.000000 4650632.000000
3 711027.625000 4651736.000000
4 711022.625000 4651519.000000
5 710482.750000 4651494.000000
6 710474.500000 4651667.000000
7 709269.750000 4651018.000000
8 709726.500000 4651604.000000
9 708926.375000 4651195.000000
10 708567.500000 4651644.000000
11 708272.750000 4651407.000000
END
1 -2.30228E+07 19,399.848 1 0 0 0
2 81,079.875 1,678.826 2 1 15 3
3 955,952.500 10,229.637 3 2 19 8
4 41,530.875 926.887 4 3 17 3
5 87,900.188 1,900.909 5 4 13 3
6 166,125.125 3,512.950 6 5 15 3
7 29,460.563 824.968 7 6 17 3
8 1022769.875 9,105.707 8 7 20 9
9 51,385.500 1,075.638 9 8 17 3
10 376,834.875 4,470.027 10 9 9 2
11 65,802.688 1,575.088 11 10 16 3
ASCII DXF Format Files to GRASS Vector
Creates the dig_plus, dig_att, and dig_cats support files.
ASCII TIGER Format Files to GRASS Vector
This program imports Census line features from TIGER records
type1 and type2 into GRASS vector format. Both pre-Census and post-Census
data formats can be used. Specific Census Feature Class Codes (CFCC)
can be extracted completely or in various combinations. These codes
are described in the TIGER/line Census Files 1990 documemtation
available from the Bureau of the Census. An additional feature code
consisting of the three letters "BOU" may also be specified to extract
a county boundary. Condensed Record 1 files may be imported with
the -c flag. These files should be identified with a trailing
"x" character on the filename.
The TIGER files must in sorted order before being used.
This can be done by using the following command:
sort TGR12113.F21 -o t12113.1 sort TGR12113.F22 -o t12113.2For consistency the sorted file should be written as above. It should consist of a 't' followed by the State and County FIPS code, then a '.' and then a value to identify the record number.