What is the granularity of the external databases for weather and soil data and how precise do my latitude/longitude need to be?
For the weather data from ERA 5, the granularity of the source data is to .25 of a degree. The actual ground distance this represents can vary per location; in the US mid-west this distance would be approx. 30 miles. When indicating latitude and longitude, this could be abbreviated to .25 with no loss of accuracy.
SoilGrids data is much more granular at 250m resolution, so there is a possibility of impact on accuracy. However, the great majority of results we see from Soil Grids for data requests return High Activity Clay, so it’s difficult to say in how many cases a less precise lat lon would give a different result.