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Using Spatial Data with SAS/GIS Software |
A SAS View contains the following elements:
SAS data sets can be indexed by one or more variables, known as key variables. SAS indexes are classified as simple or composite, according to the number of key variables whose values make up the index.
SAS/GIS Data Sets |
The chains data set also lists the from-node and to-node row numbers in the nodes data set, as well as the number of detail points and the corresponding details data set row number. The left and right side attribute values, for example, ZIP codes and FIPS codes, are also stored in the chains data set.
Managing Data Set Sizes |
Following are five actions that you can take to manage
the size of your spatial data sets. You need to perform most of these actions before
importing your data into
SAS/GIS.
For example, if you have a numeric variable that contains a code that can be a maximum of two digits, perhaps it would be better to store it in a two-digit character variable rather than in an eight-byte numeric variable. Change the variables' defined types or lengths in a DATA step after you complete the import.
Of the five actions, reducing the number of attributes is the easiest to perform. Use the Import window that you can access by selecting [Modify Composites] from the GIS Spatial Data Importing window to remove and drop unneeded composite variables from your data set as it is imported.
Data Set Variables |
The following sections describe the
variables that are specific
to each SAS/GIS data set.
Composite | Variable 1 | Variable 2 | Variable 3 | Variable 4 | Type (table note 1) | Description |
---|---|---|---|---|---|---|
ARCID | ARCIDL | ARCIDR | A or C | ARCID from the ARC/INFO coverage. Maps made from line and point coverages will not have left and right variables. | ||
ARCNUM | C | ARCNUM from the coverage. | ||||
'COVERAGE' | 'COVERAGE'_L | 'COVERAGE'_R |
A or C | This variable is derived from the input filename. It's
the last word preceding the file extension. For example,
/local/gisdata/montana.e00
would have a 'COVERAGE' (table note 2) name of
montana . The left variable would be
montanal , the right variable would be
montanar , and the composite type would be Area. Line and point coverages
do not have left- and right-side variables, and the composite type would be
Classification. |
||
AREA | AREAL | AREAR | A | AREA from the coverage. | ||
PERIMETE | PERIML | PERIMR | A | PERIMETER from the coverage. | ||
'ATTRIB' | 'ATTRIB'L | 'ATTRIB'R | All variables in the polygon, line, or point attribute tables are saved as composite variables. In the case of the polygon coverages, an L or an R is added to the end of the first five characters of the actual variable name. | |||
_COVER_ | _COVEL | _COVER | A or C | This variable contains the name stored in the 'COVERAGE' variable. | ||
_SRC_ | _SRCL | _SRCR | C | Contains the string 'ARC'. | ||
X | X | X | X coordinate. | |||
Y | Y | Y | Y coordinate. |
A = Area |
C = Classification |
X = X coordinate |
Y = Y coordinate |
Names in single quotation marks, such as 'COVERAGE' and 'ATTTRIB,' are GIS
composite names.
Composite | Variable 1 | Variable 2 | Variable 3 | Variable 4 | Type (table note 1) | Description |
---|---|---|---|---|---|---|
LMAJOR(n ) |
LMAJOR(n ) |
C | Major line attribute code. | |||
LMINOR(n ) |
LMINOR(n ) |
C | Minor line attribute code. | |||
NMAJOR(n ) |
NMAJOR(n ) |
C | Major node attribute code. | |||
NMINOR(n ) |
NMINOR(n ) |
C | Minor node attribute code. | |||
MAJOR(n ) |
AMAJORR(n ) |
AMOJORL(n ) |
A | Major area attribute code. | ||
MINOR (n ) |
AMINORL(n ) |
AMINORR(n ) |
A | Minor area attribute code. | ||
X | X | X | X coordinate. | |||
Y | Y | Y | Y coordinate. |
A = Area |
C = Classification |
X = X coordinate |
Y = Y coordinate |
Composite | Variable 1 | Variable 2 | Variable 3 | Variable 4 | Type (table note 1) | Description |
---|---|---|---|---|---|---|
'ATTRIB' | 'ATTRIB'L | 'ATTRIB'R | A or C | All polygon, line, or point attributes are saved as composite variables. In the case of polygon maps, an 'L' or 'R' is added to the end of the first seven characters of the actual variable name. |
A = Area |
C = Classification |
Composite | Variable 1 | Variable 2 | Variable 3 | Variable 4 | Type (table note 1) | Description |
---|---|---|---|---|---|---|
ID | ID | C | The ID variable from the data set. | |||
'ATTRIB' | 'ATTRIB' | 'ATTRIB' | C | Any other variable in the data set is saved as a classification composite. | ||
X | X | X | X coordinate. | |||
Y | Y | Y | Y coordinate. |
C = Classification |
X = X coordinate |
Y = Y coordinate |
Composite | Variable 1 | Variable 2 | Variable 3 | Variable 4 | Type (table note 1) | Description |
---|---|---|---|---|---|---|
ID | ID | C | The ID variable from the data set. | |||
'ATTRIB' | 'ATTRIB' | 'ATTRIB' | C | Any other variable in the data set is saved as a classification composite. | ||
X | X | X | X coordinate. | |||
Y | Y | Y | Y coordinate. |
C = Classification |
X = X coordinate |
Y = Y coordinate |
Composite | Variable 1 | Variable 2 | Variable 3 | Variable 4 | Type (table note 1) | Description |
---|---|---|---|---|---|---|
'ATTRIB' | 'ATTRIB'L | 'ATTRIB'R | A or C | All polygon, line, or point attributes are saved as composite variables. In the case of polygon maps, an 'L' or 'R' is added to the end of the first seven characters of the actual variable name. | ||
LINELYR | C | This variable is derived from the input filename. It's
the last word preceding the file extension. For example,
/local/gisdata/montana.mif
would have a LINELYR name of
montana . |
||||
PTLYR | C | This variable is derived from the input filename. It's
the last word preceding the file extension. For example,
/local/gisdata/montana.mif
would have a PTLYR name of
montana . |
||||
POLYLYR | A | This variable is derived from the input filename. It's
the last word preceding the file extension. For example,
/local/gisdata/montana.mif
would have a POLYLYR name of
montana . |
||||
'MAP' | 'MAP' | A or C | This variable is derived from the input filename. It's
the last word preceding the file extension. For example,
/local/gisdata/usa.mif , would
have a 'MAP' name of
usa . The left variable would be
usal , and the right variable would be
usar and, in this case, the composite type would be
Area . Line and point maps do not have left- and
right-side variables, and the composite would be
Classification . |
A = Area |
C = Classification |
Composite | Variable 1 | Variable 2 | Variable 3 | Variable 4 | Type (table note 1) | Description |
---|---|---|---|---|---|---|
'IDVAR'n | 'IDVAR'L | 'IDVAR'R | A | An area composite variable is created for each ID variable (IDVAR) selected by the user in the ID vars list box. In the case of polygon maps, an 'L' or 'R' is added to the end of the first seven characters of the actual variable name. |
A = Area |
Composite | Variable 1 | Variable 2 | Variable 3 | Variable 4 | Type (table note 1) | Description |
---|---|---|---|---|---|---|
ADDR | FRADDL | FRADDR | TOADDL | TOADDR | ADDR | Address range. |
BLOCK | BLOCKL | BLOCKR | A | Block number. | ||
CFCC | CFCC | C | Feature classification code. | |||
COUNTY | COUNTYL | COUNTYR | A | County FIPS code. | ||
DIRPRE | DIRPRE | ADDRP | Feature direction prefix. | |||
DIRSUF | DIRSUF | ADDRS | Feature direction suffix. | |||
FEANAME | FEANAME | C | Feature name. | |||
MCD | MCDL | MCDR | A | Minor civil division. | ||
PLACE | PLACEL | PLACER | A | Incorporated place code. | ||
RECTYPE | RECTYPE | C | Record type. | |||
STATE | STATEL | STATER | A | State FIPS code. | ||
TRACT | TRACTL | TRACTR | A | Census tract. | ||
ZIP | ZIPL | ZIPR | A | ZIP code. | ||
BG | BGL | BGR | A | Block group. | ||
LONGITUDE | X | X | Longitude. | |||
LATITUDE | Y | Y | Latitude. |
A = Area |
C = Classification |
ADDR = Address |
ADDRP = Address Prefix |
ADDRS = Address Suffix |
X = Longitude |
Y = Latitude |
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Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.