5. Problem Solving

This section will help you solve some problems or errors that may occur when using 3Di. Some issues are due to the software, these will be summarized in the section Known Issues, including a temporary solution. Errors, due to input data or other user settings can occur in various components or steps of the modeling process:

  1. Generating a 3Di model from the spatialite data or ‘INP generation’ which occurs in http://3Di.lizard.net/models, or

  2. During simulation via the live site or via an API call.

The section ‘Frequently endured issues’ below mention different types of errors and how to find them.

5.1. Known Issues

  • When applying 2D boundary conditions, it is not allowed to have more than one grid resolution on the edge. However, there is no clear error message for this.

  • In the live site it is not possible to visualize structures together with the schematisation.

  • Note, that in v2_control tables (v2_control_table, v2_control_memory, v2_control_pid, v2_control_timed) the unit for adjusting the pump discharge capacity is actually m3/s, even tough the unit used normally is L/s.

  • For simulations including interflow or embedded elements, not all results can be viewed. Moreover, the water balance ignores part of the flow, therefore it will seem to be inconsistent.

  • When using the sideview-tool in the QGIS-plugin, the length of the side view profile of pipes in the graph can be different than the actual length of the pipe. This is due to a projection conversion error in QGIS and does not affect 3Di calculations.

  • There are some issues related to projections. We are encountered this for our UK-based models (.sqlite). These models will show a shift in the geometries in QGIS. The reprojection from EPGS:27700 (British National Grid) to WGS84 is based on an outdated reprojection in the spatialite. There is a solution for this:

  1. In QGIS open the (table without geometry) table “spatial_ref_sys”

  2. go to row srid 27700

  3. update column proj4text (overwrite existing value) with +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +datum=OSGB36 +units=m +no_defs

This might also be the case for other projections.

  • Laterals currently do not work for other projection systems than epsg:28992.

  • The manhole_storage_area in the v2_global_settings table of the data base must be set as an INTEGER.

5.2. Frequently endured issues

Per category, we include the frequently endured issues. In case you think a specific issue should be included, please let us know.

5.2.1. INP generation

After uploading or pushing a new revision 3Di.lizard.net/models will generate a model automatically. If an error occurs during this process the status bar will turn red and show FAIL. By clicking FAIL the log messaging is shown. You may now look for errors either through the web page or by downloading the file in the upper right corner of the screen. Look for any line that starts with ERROR and see if you recognize the examples below.

5.2.1.1. ERROR can not detect use case from settings.

Followed by:

Settings from v2_globalsettings are: use_2d_flow True
use_1d_flow False dem_file rasters/dem.tif
conf.manhole_storage_area 100.0

The use case was not specified correctly. Check the manhole storage area given your use case (1D, 0D, 2D or an combination). Manhole storage area must be NULL when using only 2D. For other settings see the global settings section in the database overview, download here.

5.2.1.2. AttributeError: ‘NoneType’ object has no attribute ‘__tablename__’

Some tables that should be empty are not. For instance when v2_connected_pnt table (used for breaches) is filled, while your model has no 1D elements. Try emptying the tables you do not use. You can see which tables in the spatialite database are filled by dragging the spatialite into your QGIS project. A pop-up screen appears showing all geometry tables including the number of records per table. Check each table without a geometry.

5.2.1.3. TypeError: Improper geometry input type: <type ‘NoneType’>

Some feature(s) in a table with geometry has an improper geometry. This usually means the geometry field is empty. This may happen when you delete all vertices, while editing while the record in the table still exists. You must either fix the (missing) geometry or remove the given record.

5.2.1.4. ERROR: No cross section on channel with pk 558

For a channel in your model is no cross-section defined. The error displays the pk (primary key) or channel id for which channel the cross-section location is missing. Add a cross-section location and definition to the given channel.

If you expect this may be the case for multiple channels or cross-sections you can check your model using joins in QGIS. Join the definition table to the location table and see which location has no definition by opening the table. Do the same for channels; join the locations to the channel and check the table for any missing locations.

5.2.1.5. Fortran runtime error: Bad integer for item 2 in list input

Most likely you have failed to provide the channel, culvert or pipe calculation type, options are isolated, connected, embedded or double connected. Fill the calculation type for each of these tables.

5.2.1.6. ERROR : Bad integer for item 2 in list input (= network file)

Similar to the error above. In addition, for every connection node the type is derived from the connecting channels, culvert, pipes or manhole. When the node is not connected to any of these, the type cannot be derived. Add a manhole to nodes that are not connected to any channel, culvert, pipe to set the type for these nodes.

5.2.1.7. ERROR : Connected 1D calculation node at nodata value of raster.

Followed by:

Channel ID and pixel coordinates are:           2034          1681           559
ERROR  : Calculation node          18398

A connected calculation node is outside the DEM. It may be an end or start node as well as a calculation node halfway a channel segment. Check if any channels or nodes are outside the DEM and set them to isolated.

5.2.1.8. ERROR : There is at least one erroneous location of a 2D open boundary.

Followed by:

It is not located at an active edge. This (these) boundary(ies) is (are) ignored

The 2D boundary condition line is outside the DEM raster. Place 2D boundary lines in the center of the last row of pixels of the DEM.

5.2.1.9. AttributeError: ‘NoneType’ object has no attribute ‘full_name’

This error may be caused by the following:

  • One or more rasters are missing. For instance, there is no DEM given or the given them does not exists in the repository. Make sure you added it in Tortoise

  • The minimum grid space and DEM resolution are not aligned properly, the amount of pixels in the smallest computational grid cell must be an even number. Change the grid_size in the global settings or update your rasters to meet this requirement.

  • A channel may have a cross section location exactly on the start or endpoint or the profile location is not snapped to any vertex. Check your locations using geometry functions like intersect.

  • Rasters are not aligned or have different geometries. Check your rasters using Gdalinfo and Rasters.

  • Grid refinement or levees are outside the DEM.

5.2.1.10. Error in node sequence of network file

Some required fields are left blank, like the crest level of a weir. Fields may be empty in v2_orifice, v2_channel, v2_weir, v2_culvert or v2_pumpstation. Check your recent edits and compare them with the database overview.

5.2.1.11. ERROR: Error in 1d administration:

Followed by:

Number of input boundaries is not the same to the number of boundaries found by the computational core

A boundary condition is linked to a node with more than one connection. A boundary may not be spaced on a junction of multiple channels, pipes or structures. Check the elements that are linked to the connection nodes that have boundary conditions.

5.2.2. Simulation

If an error occurs during simulation a pop-up is displayed in the right bottom corner. The pop-up shows the error message and you will receive an email with some more details.

The INP generation system tries to avoid any errors during simulation. When an error during simulation does occur, most often there is a problem with one of the underlying services or servers. The user can best contact the Servicedesk for more help. The list of errors below may also help you.

5.2.2.1. ERROR - F - Matrix diagonal element, near zero

At one calculation point there is no storage area or the wet cross section area is near zero or even negative. This may be caused by various reasons listed below:

  • Structure levels are below cross section reference levels, f.i. a culvert below the bed level. This is not possible as when water level drops below the bed level, flow through the culvert has no area to flow to. Update reference or structure levels so that they match. Reference levels can be below structure levels.

  • A lateral inflow from laterals or an inflow surface is connected to a node without storage area, f.i. an pump end node or boundary node. Removes laterals or inflow from these nodes.

  • Water level boundary is below structure level.

  • All definition values for width and height must be positive.

  • Pump start level is below pump stop level.

The error is followed by a reference to the node without any storage or link without wet cross section area. This will look something like:

near zero, aii(nod)<1.0d-10,nod,aii(nod),su(nod)  14614   14439  0.0000E+00  0.0000E+00

The first number (14614 in this example) refers to the calculation node on which the error occurs. This number can be found using the QGIS plugin when a result of this model is available. The number can be located using the node_results. The id’s in this table match the one given here. The second number is a link id and can be found using the line_result layer.

5.2.2.2. ERROR : The combination of cross-section types is invalid for input channel number:

Not all cross-section definition types can be combined for a single channel. Only type 1 (rectangle) and type 2 (circle) or type 5 and 6 (both tabulated) can be combined. If you have multiple cross-section types on one channel change these or split the channel.

5.2.2.3. ERROR - F - Impossible line connection at calculation node: 729

This error may occur when using embedded in combination with structures. Make sure no structure is placed entirely inside a 2D computational cell. You can only check this when you have a copy of the 2D computational grid. You can obtain this by making a purely 2D model of your DEM and grid refinement of try making one using the ‘create grid’ function in the QGIS processing toolbox.

5.2.2.4. Runtime Error: NetCDF: String match to name in use

Check the aggregation NetCDF name settings, names must be unique.

5.2.2.5. No Limit to infiltration

The setting max_infiltration_capacity_file found in the global settings table is depricated. The setting was not removed from the global settings table, but is added to the infiltration_simple_table. Values from there are taken into account. This is solved in the autumn release 2018, however older versions of the spatialite still have this setting there.

5.2.3. Results Analysis

5.2.3.1. ThreeDiToolbox Installation

During installation and/or upgrading of the ThreeDiToolbox (QGIS Plugin), one may encounter problems. Various options are described at ThreeDiToolbox

5.2.3.2. ThreeDiGrid

The python package that can assist in analysing and making your own tools based on the 3Di results can be found at this location. The full threedigrid documentation can be found via the following link: Threedigrid documentation.

5.2.4. Servicedesk

If you are unable to find or solve an error you may contact the Nelen & Schuurmans servicedesk. The servicedesk will:

  1. always assist you in solving any problems you have using the various 3Di web pages, and

  2. help you solve problems in model schematisation if you are subscribed to 3Di support.

Contact the servicedesk by sending an email to servicedesk@nelen-schuurmans.nl. Please provide as much information as you can about the error and the model and revision number for which the error occurs.