Topological Validation

Validating Topologies

Topological validation is an integral part of GIS. Being able to verify if your geometries meet predefined rules is especially useful in data creation or modification, to ensure that your data is valid. For example, if you have a sampling area and want to ensure that sample points are always within the same area, there's a way to validate for that. Other possible validations includes rules like 'points are always on lines' or 'lines may never intersect'.

Another common scenario where validation might come in handy is when handling counties within a state. You could apply a validation rule to test that there are no gaps between polygons, to ensure that there is total coverage of the area. Another useful validation in that case would be a rule ensuring that all county polygons are within the given state polygon. ThinkGeo offers a number of APIs that cover the main types of validation, and can be combined to build up nearly any rule you can imagine.

 
Image showing points being validated based on whether they are on a line

Point Validation

Validating your points helps ensure the integrity of your data when editing. By passing in your points and comparison features, our APIs allow you to quickly determine if any rules were broken, as well as providing feedback as to where any violations occurred.

Sample Code

WPF | Winforms | MAUI | WebAPI* | Blazor*

 
Image showing points being validated based on whether they are touching a line

Touching Lines

Image showing points being validated based on whether they are touching a line's endpoints

Touching Line Endpoints

Touching Poly Boundaries

 
Within Polygons

Within Polygons

 
Image showing lines being validated based on whether they are self-intersecting

Line Validation

Ensuring that lines conform to your scenarios is invaluable. Our APIs can be used to ensure that new streets being digitized never overlap with other lines, or that they do not cross themselves. When combined with other validations, these can help you avoid little mistakes that might slip through when editing shapes.

Sample Code

WPF | Winforms | MAUI | WebAPI* | Blazor*

 

Single Part (Not Multiple Strings)

No Intersects

No Overlap With Lines

 

Overlapping Polygon Boundaries

No Self-touch

No self-intersection

 
Touch Points

Touch Points

Forms a Polygon

No Pseudo-nodes

 

No Overlap

No Self-Overlap

Lines Must Overlap

Lines Must Overlap

Image showing polygons being validated based on whether they are within another polygon

Polygon Validation

Our polygon validation APIs allow you to quickly check sets of polygons against a variety of rules - for example, 'polygons must not overlap' or 'a set of polygons must be within a larger polygon'. These can be useful for many real world use cases, like validating that states or providences are within the boundaries of a country, or that county polygons are not overlapping.

Sample Code

WPF | Winforms | MAUI | WebAPI* | Blazor*

 

Polygons Must Be Within Polygons

Union Of Polygons Must Not Have Gaps

Polygon Boundaries Must Overlap

 

Polygon Boundaries Must Overlap Lines

Polygons Must Contain Points

Polygons Must Not Overlap Polygons

Polygons Must Not Overlap Polygons

 

Polygons Must Not Overlap

Polygon Must Overlap Polygons

Polygons Must Overlap Each Other

 * Feature available, but no specific sample.