# GIS Approach for Expressing Structural Landforms: Forms, Elements, and Relationships
## 2 GIS Approach for Expressing Structural Landforms
### Definition of Structural Landforms Based on Spatial Objects and Topological Rules
\begin{table}
\begin{tabular}{p{85.4 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Morphological Types** & **Relationship between Elements** & **Topological Rules** \\ \hline Mesa & The **terrane** occurrence is horizontal, the **lithology** is hard, and the **stratigraphic boundary** is parallel to the **contour line**. & Rule1: **Terrane** (horizontal) Must be covered by **Rock** (hard) \\  & The **terrane** occurrence is horizontal, the **lithology** is hard, and the **stratigraphic boundary** is parallel to the **contour line**. & Rule2: **Contour_Line** Must be covered by feature class of **Stratigraphic_Boundary** \\ \hline Anticlinal Mountain & The stratum in the **core of the fold** is older in age, and the **fold axis** coincides with the **ridge line**. & Rule1: **Core_of_Fold** Must be covered by **Stratum** (Older Stratum) \\  & The **terrane** occurrence is horizontal, the **lithology** is hard, and the **stratigraphic boundary** is parallel to the **contour line**. & Rule2: **Folding_Axis** Must be covered by feature class of **RidgeLine** \\ \hline Synclinal Mountain & The stratum in the **core of the fold** is younger in age, and the **fold axis** coincides with the **ridge line**. & Rule1: **Core_of_Fold** Must be covered by **Stratum** (Older Stratum) \\ \hline Anticlinal Valley & The stratum in the **core of the fold** is older in age, and the **fold axis** coincides with the **valley line**. & Rule1: **Core_of_Fold** Must be covered by feature class of **Stratum** (Younger Stratum) \\ \hline Synclinal Valley & The stratum in the **core of the fold** is younger in age, and the **fold axis** coincides with the **valley line**. & Rule1: **Core_of_Fold** Must be covered by feature class of **Stratum** (Younger Stratum) \\ \hline Cuesta & The **terrane** occurrence is inclined, the **lithology** is hard, and the **ridge line** coincides with the **stratigraphic boundary**. & Rule1: **Terrane** (Occurrence dip \(<\) 25\({}^{\circ}\)) Must be covered by **Rock** (hard) \\  & The **terrane** occurrence is inclined, and **the **contour line** coincide with the **stratigraphic boundary**. & Rule2: **Ridge_Line** Must be covered by feature class of **Stratigraphic_Boundary** \\ \hline Hogback Mountain & The **terrane** occurrence is inclined, and **the **contour line** coincide with the **stratigraphic boundary**. & Rule1: **Terrane** (Occurrence dip \(<\) 25\({}^{\circ}\)) Must be covered by **Rock** (hard) \\ \hline Fault Block Mountain & The **terrane** occurrence is inclined, and the **contour line** coincide with the **stratigraphic boundary**. & Rule1: **Fault_Wall** (upper) Area boundary must be covered by boundary of **Fault_Wall** (lower) \\  & The **fault** line overlaps with the **valley line**, and the **upper and lower plates of **the **fault wall** are relative displacements. & Rule2: **Fault_Line** Must be covered by feature class of **RidgeLine** \\ \hline Fault Valley & The **fault line** overlaps with the **valley line**, and the **upper and lower plates of the **fault wall** are relative displacements. & Rule1: **Fault_Wall** (upper) Area boundary must be covered by boundary of **Fault_Wall** (lower) \\  & The **fault wall** is the **valley line**, and the **upper and lower plates of **the **fault wall** are relative displacements. & Rule2: **Fault_Line** Must be covered by feature class of **ValleyLine** \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Corresponding descriptions of the relationships between the elements and topological rules of structural landforms.