FAQ/ Can you predict flooding for the entire land area of the earth?¶
I would like to give global rainfall data to DioVISTA to predict flooding over the entire land area of the earth, but is it possible? The rainfall data we want to give is a 1200 x 3600 array data of 0.1°N grid, 60°N ~ 60°S, 0°~360E longitude, stored in netCDF.
In this environment, the data can be read, but when I run the simulation, I get an error message that there is not enough memory.
response¶
It is not possible to perform flood analysis by providing rainfall data for the entire global land area. This is due to the following specifications:
- DioVISTA simulation models do not use coordinates that can handle the entire sphere at once. It uses coordinates that expand a part of the earth, which is an ellipsoid, onto a plane. DioVISTA uses either a UTM coordinate system or a standard area mesh. These coordinates assume that the Earth is flat. This assumption often holds near the origin of the coordinates, but not at points away from the origin. At points away from the origin, the coordinate distance will be very different from the actual distance.
- During the model initialization process, it attempts to expand the mesh across an area with rainfall data. Therefore, if rainfall data is in a wide area, even if a very small calculation area is set, the initialization of the model will cause insufficient memory.
Possible workarounds include the following: Instead of creating a project that covers the entire planet, divide the globe into regions and create a project for each region. Rainfall data is also segmented by project. For example, the UTM coordinate system divides the entire globe into 120 zones, so it should be divided into at least similar regions.