Analysis of similarities and differences of various merged features (Union, merge, append, resolve) in ArcGIS

Reprinted from CSDN Blogger 「Sylvenas」 The original article of
Link to the original text ：[https://blog.csdn.net/Mello_/article/details/41276909]
Based on the original text, this paper adds some contents , Thank you for sharing

ArcGIS Merging two feature classes into one feature has Union、Dissolve、Append、Merge etc. , stay Arctoolbox There are corresponding tools in , But the function is different ：

Union： Merge input feature classes into new feature classes .

• graphics ：union Can only merge polygon The element class of type . When two feature classes are merged, the intersecting parts are processed , Make it a multi part element , And there are options to allow gaps （gaps） Or no gap is allowed . If you choose not to allow gaps , The gap after the two feature classes are merged will generate features .
• Property sheet ：union There are three options for merging property sheets ：all、no_fid and only_fid.all Put the attribute table fields of the two feature classes in the attribute table of the output feature class in order in , Include fid. A field with the same name （ except fid Outside ） Add a number after the field name to show the difference （fid Add the feature class name ）.no_fid Divide the attribute table of two feature classes by fid The fields outside are in order The sequence is all placed in the attribute table of the output feature class .only_fid Only... In the attribute table of two feature classes fid Put it in the attribute table of the output feature class , stay fid Add the feature class name to show the difference . union No field mapping .
  

Merge： Merge input feature classes 、 Table to new feature class 、 In the table .
You can combine general attribute tables , Merge attribute or hook attribute ！
for example ： county polygon, Only name attribute , Now you need to add his zip code 、 Area code 、 Population 、 area 、 Code and so on , Now I have collected this information , And put it into the general attribute database, such as access Inside . Attribute tables and graphic attributes have a common name attribute field , Sure joins Together , And then use Merge Tools , Select the desired attribute field , Generate Independent new elements ！

• graphics ：merge You can merge points 、 Line 、 Polygon and other feature classes and tables , But it must be of the same type .merge Do not process elements , Simply put the elements into a feature class , Therefore, the output feature classes may have overlaps or gaps .

Before the merger

After the merger

• Property sheet ：merge When processing the property sheet, fields with the same name are combined into one , For fields with different names, press the original name 、 Add all of them to the output feature class attribute table in sequence , primary fid Will discard .merge Field mapping is possible .

Append： Merge input feature classes 、 surface 、 Raster image and raster catalog to an existing feature class 、 surface 、 Grid image and grid directory .
If the field properties of the source data are the same , You can use append Merge multiple shapefile The document is a .
Such as rivers of different levels shapefile file , Can be merged into one shapefile in , Display topics can also be described separately .

When schema type The options are test when , The attribute table structure of input and output feature classes must be consistent , Field name 、 type 、 The order of arrangement must be exactly the same , When schema type The options are no_test Time can be different .

• graphics ：append You can merge points 、 Line 、 Polygon and other feature classes and tables 、 Raster image and raster catalog , But it must be of the same type .append Do not process elements , Simply put the elements into a feature class , Therefore, the output feature classes may have overlaps or gaps .

append result

• Property sheet ： The same as the attribute table of the output feature class . Fields in the input feature class attribute table will be discarded if they are not in the output feature class attribute table , But you can do field mapping , Map a field of the input feature class to a field of the output feature class .

Dissolve: Multiple elements can be , Through the specified attribute ( Same property value ), Dissolve into an element ;
Add ： Individuals understand that the same attributes are merged into one feature class .
for example ： You can put the county Dissolve into market . Conditions ： There are common elements in the county City sign ~!
dissolve/ Missing a different attribute that is not specified

dissolve front dissolve after

Similarities and differences ：merge、union、append All are consolidated , Start , The process , result , What's the difference ？

merge and union Generally speaking, it is used for “ elements ” Speaking of , in other words , Operate on certain elements . merge It is an operation on the features in the same feature class , After the operation is completed, the original elements disappear . union Be flexible , You can operate on features of different layers , New features are generated in the target layer append It is generally used to merge multiple feature classes . For example, merge the data of two provinces into one feature class .