In relation to using RORB for smaller urban developments, the areas and lengths have many decimal places given the units are km^2 and km respectively. When creating catchment file in GE, the data recorded in the catg file truncates values to 4 decimals (I think 4 is correct). While I understand these can be manually adjusted in the text editor, you have to be careful not to save the catg file again else you overwrite the manual changes.
Could there be alternative unit options assigned ?, or allow the GE to save values to more decimal places ?
Thanks for your post. Yes, this is an issue with the GE for small sub-areas/reaches.
As you have identified, the work-around is to edit the reach length and sub-area area data directly into the catchment file using a text editor. When you do this, you will need to adjust the data being used in the actual RORB control codes which start below the GE data.
Having done this, it is best not to edit the file again in the GE or you will overwrite your changes.
We’ll add this onto the bug/enhancements list and try to get it fixed in the next release. It would be helpful if you and other users could provide some feedback on the size of the smallest sub-areas you have worked with to ensure that we can capture these.