Esri_intersect
Computes the geometric intersection of two themes. Only those features in the area common to both are preserved. Feature attributes from both themes are joined in the output theme.
Dialog Command: esri_intersect Input theme (?/<default>):
Intersect theme (?):
Output theme (?):
Fuzzy tolerance <compute>:
Usage Input theme (?/<default>):
The theme that will be overlaid with the Intersect theme. The specified theme must be a point, line or polygon theme. Entering a question mark (?) will execute the listthm command to list all themes in the current drawing.
Intersect theme (?):
The overlay theme containing polygon features. This must be a polygon theme.
Entering a question mark (?) will execute the listthm command to list all themes in the current drawing.
Output theme (?):
The theme to be created. If Output theme has not been defined,
esri_intersect will prompt for its creation. Output theme has the same feature class as Input theme. Entering a question mark (?) will execute the listthm command to list all themes in the current drawing.
Fuzzy tolerance <compute>:
The fuzzy tolerance is the minimum distance between coordinates in the Output theme. By default, the minimum fuzzy tolerance value from the Input theme or the Intersect theme is used. Compute is determined as follows:
1) The tolerance values are read from the themes’ TOL files if they exist.
(Refer to the esri_tolerance command for more information on the TOL file.) 2) If the TOL files do not exist and the width of the theme’s BND is between 1 and 100, the fuzzy tolerance is set to 0.002.
3) Otherwise, the tolerance is 1/10,000 of the width or height of the theme’s BND, whichever is greater.
If you explicitly specify a value instead of selecting the default compute option, ArcCAD saves that value into the Output theme’s TOL file.
Notes
G e n e r a l The feature attribute table for Output theme contains items from the feature attribute tables of both the Input theme and the Intersect theme. Attributes of the Input theme and Intersect theme that are to be retained in Output theme
must have unique item names. If a duplicate item name is encountered when the attributes of the Input theme and Intersect theme are being joined, the priority for the item definitions and values will be first those from Input theme and then those from Intersect theme. Therefore, if Input theme and Intersect theme
items have the same name, only the Input theme items are preserved in the output theme.
Topology is constructed for Output theme. All internal items of the feature attribute table will be resized to ArcCAD default widths.
ITEM WIDTH TYPE N.DEC AREA 13 N 6 PERIMETER 13 N 6 FNODE_ 11 N 0 TNODE_ 11 N 0 LPOLY_ 11 N 0 RPOLY_ 11 N 0 LENGTH 13 N 6 INTERNAL_ID 11 N 0 USER_ID 11 N 0
If the Input theme is a polygon theme, label points are generated in each
Output theme polygon feature. The polygon User-ID is set equal to the polygon Internal-ID number minus one.
The tics of Output theme are copied from the Input theme.
Annotation is copied from the Input theme and saved in the Output theme. MEMO items in the Input theme or in the Identity theme will not be written to the Output theme.
Discussion The esri_intersect command creates a new theme by overlaying two sets of features. The Output theme contains only those portions of features that are in the area occupied by both the Input theme and the Intersect theme.
features can be polygons, lines, or points.
Esri_intersect
intersect with the polygons of the Intersect theme. Topology is built for the
Output theme.
Feature attribute tables are also updated. The feature attribute table for the
Output theme contains items from both the Input and Intersect theme attribute tables. Items are merged using the old internal number of each feature. First the Input theme items are joined into the Output theme’s feature attribute table;
then the Intersect theme items are joined. The following table lists the items that are saved in the attribute tables for the Output theme.
For polygon or point input themes For line input themes
- AREA - FNODE_
- PERIMETER - TNODE_
- Output themefeature Internal-ID number - LPOLY_
- Output themefeature User-ID - RPOLY_
- Input themefeature Internal-ID number - Output themefeature Internal-ID number - Input themefeature User-ID - Output themefeature User-ID
- all subsequent Input theme - Input themefeature Internal-ID number
PAT items - Input themefeature User-ID
. - all subsequent Input theme
. AAT items
. .
- Intersect theme feature Internal-ID number .
- Intersect theme feature User-ID - Intersect themefeature Internal-ID number - all subsequent Intersect theme - Intersect themefeature User-ID
PAT items - all subsequent Intersect theme
. PAT items
. .
. .
. .
Items saved in the feature attribute tables for the output theme
If the Input theme is a polygon theme, only those portions of the polygons contained in areas occupied by both the Input and Intersect themes are saved in the Output theme. Input theme arc features are split at their intersection with polygons of the Intersect theme. The resulting arc features are used to build polygons.
Input theme Intersect theme Output theme
1
If the Input theme is a polygon theme
Esri_intersect
If the Input theme is a line theme, Input theme arc features (or portions of them) are preserved only if they fall within a polygon or along a polygon boundary of the Intersect theme. The LPOLY and RPOLY values for each resulting arc feature are updated to contain the numbers of the Intersect theme polygon features that are to its left and right sides. Running clean or build on the Output theme will reset and overwrite the LPOLY and RPOLY item values in the Output theme’s AAT to the topology of Output theme. If the LPOLY and RPOLY information from the polygons of the Intersect theme is required for future analyses, add two new items to the Output theme AAT and copy the values of LPOLY and RPOLY to them before using clean or build.
OUTPUT
If the Input theme is a line theme
If the Input theme is a point theme, only those points that fall within a polygon of the Intersect theme are saved in the Output theme. The Output theme PAT lists the Intersect theme polygon within which each point falls.
OUTPUT
Input theme Intersect theme Output theme
1 If the input theme is a point theme
Related Commands
identity - Computes the geometric intersection of two themes. Only those features overlaying the feature extent of the first specified theme are preserved. Feature attributes from both themes are joined in the output theme.
esri_union - Computes the geometric intersection of two polygon themes. All features and attributes of both themes are preserved.