Check whether the 2D cell size is appropriate to reproduce the topography needed to satisfactorily meet the objectives of the study (see Section 3.1).
Topography
The topography review should focus on:
correct interrogation of DTM;
correct datum;
modifications to the base data (eg. breaklines) have been checked.
Regarding the latter, this is effectively carried out by producing a _zpt GIS check file (see Table 7 .29) using Write Check Files. The _zpt layer contains all modifications including any flow constriction adjustments. A DTM can be created from the Zpts using Vertical Mapper, or other 3D surface software, to aid in the review. Note: Reviewing the elevations in the .2dm file is not appropriate as only the ZH Zpt is represented in the .2dm file (the ZH elevation is not used in the hydrodynamic calculations).