FAQ

Section 5 of the original wiki, brought up to date. For anything not answered here, see Troubleshooting and error message handling.

What is a condition?

A planning state: one folder under 01_Conditions/ holding the terrain, sediment and hydraulic rasters for a single situation. Conventionally a four-digit year followed by a label - 2100_sample, 2008_existing, 2008_with_project. Every analysis runs against a condition, and comparing two conditions is how a project is evaluated. See Get started, terminology and signposts.

Do I need ArcGIS, an Esri licence or Spatial Analyst?

No. That is the point of this release. The geoprocessing runs on GDAL through rasterio, with numpy and scipy for the algebra. Nothing in the analysis chain needs a licence, and it runs on Linux, macOS and Windows.

Do I need QGIS?

Only for the Maps tab. Every analysis module works without it, and the tab degrades gracefully with a message rather than failing. See Maps.

How do I change map styles?

Layer styles are QGIS .qml files in the package’s templates/symbology/. Edit them in QGIS and save over the file, or point the Maps tab at your own. riverarchitect-lyrx2qml converts an existing ArcGIS Pro .lyrx.

Why is my lifespan map empty, or much smaller than I expected?

Almost always a missing input rather than a bug. A criterion whose raster the condition does not have is skipped, not failed - so a feature keyed to depth-to-water-table maps nothing useful without d2w.tif. Run Get started, terminology and signposts first. Second most common: the feature is restricted to morphological units that your mu.tif does not contain.

Why are cells with a long lifespan NoData instead of a large number?

Because their lifespan is longer than the largest modelled flood and cannot be quantified from the data. Writing a number there would be inventing one. Model a larger discharge if you need to resolve them.

Several features report exactly the same mapped area. Is that a bug?

No. Features can differ in their hydraulic thresholds and still share a spatial mask - at the largest floods every cell inside a shared depth-to-water-table band fails eventually, so the mapped extent is identical even though the lifespans within it are not.

The Max Lifespan shares add up to more than 100%.

Ties are kept rather than broken: a cell where two features both reach the maximum lifespan appears in both layers. That is deliberate - it tells you the choice is yours.

Why can I not compute SHArea?

SHArea needs a flow duration curve for that species and lifestage, in 00_Flows/<condition>/flow_duration_<code>.xlsx. Build one from a daily flow record with Get Started ▸ analyze flows (riverarchitect.flows).

Which discharges does an analysis use?

Lifespan mapping uses only the discharges listed in input_definitions.inp, because only those carry a flood return period. The ecohydraulic modules scan the condition folder and use every h<Q>.tif on disk. On the sample reach that is 17 against 60.

Do I have to convert my rasters when I switch the unit system?

No - and the switch does not convert them either. The Units menu states what your data already is. A mismatch does not raise an error anywhere; it silently applies the wrong thresholds.

Can I use the modules without the interface?

Yes. Every tab is a thin front end over an ordinary Python module. See Quickstart and the API reference.

Is everything from the ArcGIS version here now?

Every analysis module is, including River Builder (Morphology (Terraforming)) and Project Maker (Project Maker), which were the last two. What remains unported is the pool-riffle morphology designer (Tools), which never depended on arcpy, and the velocity criterion of Stranding Risk (Ecohydraulics). Both are called out where they belong.

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