Topology (ZZ) in ArcGIS)

1. first look at the implementation of the topology in ArcInfo:
Geodatabase became a new spatial data model after ArcGIS 8. It uses an open structure to store spatial data (including vector, raster, image, and three-dimensional terrain) and its related attribute data in the DBMS of the industrial standard database management system. A Feature Class, such as a river, a border, a parcel, or a pole, corresponds to a table in the DBMS, and a specific Feature) it is a record in the table. A group of spatial element classes with common spatial references can form a larger structure, known as a Feature Data Set ). In addition to spatial element classes, Geodatabase can also establish relational classes, ry networks, define element subtypes, Value domains, and rules. All element classes can be defined and extended using common CASE tools such as Visio and Rational Rose.
Geodatabase introduces topological relationship rules. Topological Relationship rules can act on different element classes in the same element dataset or different elements in the same element class. You can specify the topological relationship constraints that space data must meet, such as the adjacent relationship, connection relationship, overlay relationship, intersection relationship, and overlap between elements. All these links correspond to corresponding rules. For example, in the application of land survey and planning, there cannot be "excludes" between two adjacent plots. We can have a rule: "There cannot be gaps between adjacent polygon ". Another example is that when a river is used as a national border, provincial border, or any border, the river (line) and the boundary must be consistent. The rule can be used: "The line must be covered by the polygon edge ". You can choose a combination of several rules to flexibly specify the topological relationships that must be met by the spatial data. In order to check and maintain the correctness of the topological relationship of the spatial data, a set of (edit) tools are provided in ArcGIS Desktop to edit the spatial data according to the topology relationship rules specified by the user, it also helps users detect possible topology errors in a timely manner.
Geodatabase does not actually save the topological relationship. Public points and public edges among different element classes are dynamically detected during topology editing. For example, if we select a line and edit it, Geodatabase will automatically detect all other elements with common geometric elements for this line element. When we modify this line element, the system automatically maintains all public and public vertices to maintain their topological relationships. The benefit of this implementation method is that it can maintain topological relationships locally and selectively, with high efficiency.
In addition to the topological relationship rules, you must specify the types of elements that participate in the topology constraints, including the cluster tolerance and coordinate accuracy rank ). Here, the volume limit refers to all the points falling within the circular area with the radius as the same and will be captured together. The precision level indicates that each element class involved in the topology constraints can be artificially assigned a precision level. The higher the precision level, the more stable the element class will be when it needs to be moved within the Capacity Limit Range, that is: low-level users must move closer to high-level users. When the data precision of different element types is inconsistent, users with higher precision should be set to a higher level.
2. Let's look at the topology implementation process and interface functions in ArcEngine:
First, as a relatively advanced function, the topology needs to register the corresponding function code in the program. The interface required to implement this step is: IAoInitialize, which has the Initialize method and must be used before any other component. It can Initialize a product code. This is the method declaration format of C #: public esriLicenseStatus Initialize (esriLicenseProductCode ProductCode );
EsriLicenseProductCode has six constants. Here we will use esriLicenseProductCodeEngineGeoDB.
The following describes the structure process of topology implementation: First, you need to obtain the workspace and define the IWorkspaceFactory interface. Its function is to open the corresponding database file and then assign the IFeatureWorkspace interface, then obtain the corresponding dataset interface IFeatureDataset, assign IFeatureDataset to ITopologyContainer to obtain the topology set of the dataset, and then create a specific topology class using the CreateTopology method of ITopologyContainer, in this way, the topology of the corresponding dataset is created. Then, you can set the properties of this topology through some interfaces and functions: layer, capacity limit, precision level, and topological relationship rules. Finally, you can use the ValidateTopology method to execute this topology. We can see that its implementation process is the same as above.
3. geodatabase-related topology rules
　　
Polygon topology
1. must not overlay: single element class, polygon elements cannot overlap with each other
2. must not have gaps: Single-element class. There cannot be blank areas (non-data areas) in the consecutive polygon areas)
3. contains point: polygon + point. The boundary of each element of the polygon element class must contain at least one point in the vertex layer.
4. boundary must be covered by: polygon + line. The boundary Layer boundary overlaps with the line layer (the line layer can have more non-overlapping elements)
5. must be covered by feature class of: polygon + polygon, the first polygon layer must be completely covered by the second (the relationship between the Province and the country)
6. must be covered by: polygon + polygon. The first polygon layer must completely overwrite the second one (the relationship between China and the province)
7. must not overlay with: polygon + polygon. The polygon of two Polygon Layers cannot have a pair of overlapping elements.
8. must cover each other: polygon + polygon. The elements of the two polygon must overlap completely.
9. area boundary must be covered by boundary of: polygon + polygon. Each element of the first polygon must be completely overwritten by one or more polygon of the second polygon.
10. must be properly inside polygons: Point + polygon. All elements of the Point layer must be within the polygon.
11. must be covered by boundary of: Point + polygon. The point must be on the boundary of the polygon.
　　
Line topology
1. must not have dangle: line, cannot have hanging nodes
2. must not have pseudo-node: line, cannot have pseudo nodes
3. must not overlay: line, cannot overlap with line (between different elements)
4. must not self overlay: line. One element cannot overwrite itself.
5. must not intersect: line, cannot be wired to cross (between different elements)
6. must not self intersect: line, cannot be self-Crossover
7. must not intersect or touch interrior: Line, which cannot overlap or overlap
8. must be single part: line. A line element can only consist of one path.
9. must not covered with: line + line, two layers of lines cannot overlap
10. must be covered by feature class of: line + line, two layers of lines completely overlap
11. endpoint must be covered by: line + point. The end point in the line layer must overlap with some (or all) points in the point layer.
12. must be covered by boundary of: line + polygon, line overlapped by Polygon boundary
13. must be covered by endpoint of: Point + line. The point is completely overlapped by the end point.
14. point must be covered by line: point + line. All vertices are online.

 

 

 

Modify common topology errors The content is very comprehensive, reproduced: Geographic China http://www.geochina.net/thread-640-1-1.html 1. The planes cannot overlap each other (must not overlap) There are several ways to modify: 1. You can directly modify the element nodes to remove overlapping parts. 2. Right-click the error and select merge to merge the overlapping parts into one of them. 3. Right-click the error and select create feature to generate a new element for the overlapping part. Then, use merge under the editor to merge the generated surface into an adjacent surface. 4. Use clip under the editor to directly crop the overlapping part. 2. There cannot be gaps in the surface (must not have gaps) 1. You can directly modify the element nodes to remove overlapping parts. 2. Right-click the error and select create feature to generate a new element for the gap section. Then, use merge under the editor to merge the generated faces into adjacent ones. 3. Select auto-complete polygon in the task and use the sketch tool to automatically complete the polygon. Two polygon are automatically generated in the gap area, and then merged into adjacent surfaces using merge. Note: When you check the surface gap, the exclusive circle on the top of the surface is considered as the gap. This can be noted as an exception. 3. lines cannot be intersecting (check that line elements cannot overlap rules include online elements that cannot be overlapped) 1. If it is completely overlapped, you can select one of them for deletion, or use the related functions in the spatial etl tool to delete duplicate lines. 2. You can right-click an error and select subtract to remove duplicate parts. 3. Directly remove line overlaps with plane crossover lines and interrupt the intersection lines. The specific usage is to select a line. Click the plane crossover tool on the topology toolbar. 4. lines cannot be suspended 1. Modify the cables according to the actual situation to eliminate hanging wires. 2. You can right-click all hanging errors in the topology Error List to automatically extend and crop them. When extending or cropping, you need to enter an error distance. A hanging line smaller than this distance will be automatically extended or cropped. Five other errors 1. Multiple Elements A. You can scatter elements on the toolbar of the advanced editing tool. B. Use the multipart to singlepart in the toolbox directly. 2. Repair of surface elements and linear elements Problems retries red with this tool: · Null geometry-The feature will be deleted from the feature class. · Short segment-The geometry's short segment will be deleted. · Incorrect ring ordering-The geometry will be updated to have correct ring ordering. · Incorrect segment orientation-The geometry will be updated to have correct segment orientation. · Self intersections-The geometry's segments that intersect will be split at their intersection. · Unclosed rings-The unclosed rings will be closed. · Empty parts-The parts that are null or empty will be deleted. Vi. Specific cases Take the land use status database as an Example The rules to be checked are as follows: After drawing an arc in mdb and converting it to shp and then to MDB, the line and surface deformation at the arc may overlap and gaps. The conventional modification method will be very troublesome, so we need to use other methods for processing. Csdn Blog version 3.1a

 

Steps of ARCGIS topology check and techniques for correcting topology errors

From http://www.3snews.net/bbs/viewthread.php? Tid = 3006 and http://blog.sina.com.cn/s/blog_4d0d397d0100aasm.html

 

Before applying data manually or automatically, check and correct various topology errors as required!
Geographic Data is massive and massive. errors can occur if it is artificial or automatic vectoring. For data with a large amount of data, checking and correcting errors is a tedious and complex task with a heavy workload.

  Based on the past several years of exploration experience, we have summarized several methods for discussion. You are welcome to join in the discussion and correct me!
1. On the workstation, edit the check data. This method requires that the source data be coverage and be operated on a dark interface,

 Although you can also set the editing menu, you still need to use a lot of commands in general, which is troublesome.

Step 1: Convert the file Coverage format, go to catalog, and set its capacity limits (in file Properties Tolerance item, set according to precision requirements)
Second, do not: Go to arc to modify it!
                    Start the arc environment of workstation and enter AE (Note: arcedit), ec + (Cov file path)
For specific command formats, enter help to view help
The command to display the hanging lines is: de Arc Node Dangle ; Press ENTER
Nodec Dangle 2   Enter
Disp999, enter
Draw, press ENTER
In this way, all the hanging lines are displayed in red for the connected line errors. Next, you only need to use the corresponding command to process and modify the lines!
We recommend that you perform build on the layer before the modification, so that many minor errors will be automatically processed back. Make sure to select the parameter!

 

2. Load data such as a personal geographic database and use the topology function to automatically check data errors

(This method can be implemented In arcmap with friendly interface and is suitable for modifying not many topology errors)

Start ArcCatlalog;
Select a local directory, right-click the directory, and choose create from the shortcut menu to create a personal. GeoDatabase ";
Right-click the created GeoDatabase, and choose "New"> "dataset". Set the coordinate system of the dataset, if you are not sure, select the coordinate system of the data you want to analyze;
Right-click the dataset you just created and choose ">" Import element class inport ". -- Feature Class Single ", import the data you want to perform topology analysis;
Select the dataset you just created, right-click the dataset, and choose create from the shortcut menu. In the displayed dialog box, create a topology and add a topology processing rule;
Topology analysis.
Finally, open the file generated by the topology rule In arcmap and modify the error record information in the topolopy toolbar.
Import the dataset to ARCMAP and click edit to edit the dataset.
Open the eidt drop-down menu and select more Editing Tools -- topology the topology editing toolbar is displayed.
Select the data for the topology and click "Open error ". Inspector button.
In error Click search in the inspector dialog box. Now to locate all topology errors.
Mark a linear error As Exception.
Check polygon errors one by one. First select the wrong small class and right-click to select zoom To, then click merge, select the appropriate graph class for merge processing, so that the small class information will not be lost.

 

 Another statement:

Use catalog Create a personal geographic database and a new featuredataset
Import the shp file to featuredataset.
Right-click featuredataset and choose new topoloy data layer,
Click Next and select the imported shp layer. Next, add the topology check rules. This step is very important. You need to display broken lines, unattached lines, and early lines, select the corresponding topology rules! Click next after the selection.
Catalog generates a topology check layer file and uses arcmap to open the file.
You can see the error you need to display, so you can use the editing tool to modify it much more conveniently.