Rules for Merging Feature Attributes
If you delete a feature code for a point and replace it with a new feature code in the Feature Code Editor, the attributes for the original code are displayed along with the attributes for the new code.
If the original feature code and the new feature code share a common attribute, the attribute is listed only once in the attributes list for the new code, and it is populated with the value that was entered for the original code. However, this value is editable, along with any attributes that are unique to the new code.
If the original feature code includes an attribute that is not shared with the new feature code, it is included in the attributes list for the new code, but it is not editable and it is not used for feature code processing. It is listed as "unknown" in the "Problematic Attribute" section of the Feature Code Processing Report. Optionally, you can delete this attribute from the list.
As an example, say the feature code "em" ("electric meter") was originally assigned to a point. This code includes two attributes: "height" and "type." You then replace "em" with the feature code "pp" ("power pole"). This new code also includes two attributes: "height" and "diameter."
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Feature code: |
Attributes: |
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"em" |
"height" "type" |
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"pp" |
"height" "diameter" |
In this case, three attributes would be included in the attributes list for "pp":
- The "height" attribute is common to both feature codes, so it is displayed once in the attributes list. It includes the value originally entered for the feature code "em." However, you can change this value.
- The "diameter" attribute is unique to the new "pp" feature code, so it is displayed in the attributes list with no value. You can enter a value.
- The "type" attribute is unique to the original "em" feature code, so it is displayed in the attributes list with the value originally entered. However, this attribute is not editable and is not used for feature code processing.
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Feature code: |
Attributes: |
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"pp" |
"height" (original value, editable) "diameter" (new value) "type" (original value, non-editable) |
In the case of multiple feature codes being assigned to a point, the order of the codes before and after editing determine where the attributes in the original feature codes and new feature codes are merged. For example:
- If "em pp" ("electric meter" and "power pole") is changed to "et pp" ("electric transformer pad" and "power pole"), the attributes for "em" and "et" are merged as described above. The attributes for "pp" are unaffected.
- If "em pp" ("electric meter" and "power pole") is changed to "etb" ("electric transformer box"), the attributes for "em" and "etb" are merged as described above. The attributes for "pp" are not kept.
- If "em pp et" ("electric meter," "power pole," and "electric transformer pad") is changed to "etb elc" ("electric transformer box" and "electric conduit"), the attributes for "em" and "etb" are merged as described above. The attributes for "pp" and "elc" are merged as well. The attributes for "et" are not kept.
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Feature codes: |
Attributes: |
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"em pp" is changed to "et pp" |
"em" and "et" attributes are merged "pp" attributes are unaffected |
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"em pp" is changed to "etb" |
"em" and "etb" attributes are merged "pp" attributes are not kept |
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"em pp et" is changed to "etb elc" |
"em" and "etb" attributes are merged "pp" and "elc" attributes are merged "et" attributes are not kept |
