--- title: "OF collect survey entry relevant only for unknown and unlisted species" url: "https://openforis.support/questions/2232/of-collect-survey-entry-relevant-only-for-unknown-and-unlisted-species" tags: ["collect"] status: "accepted" score: 0 answer_count: 1 asked: "2019-04-01T06:06:11" last_activity: "2019-04-01T10:09:57" source: "Open Foris Support - Q&A Forum" license: "Copyright Open Foris, 2026. Some rights reserved under creative commons license." --- # OF collect survey entry relevant only for unknown and unlisted species Asked by GaelS on 2019-04-01 I would like to know if it is feasible and what would be the expression to have a new entry in a survey that would only be relevant when the tree species is unknown or unlisted. I have added manually entries in the tree species list for Unknown or Unlisted species as follows: no / code / family / scientific_name / synonyms / khm 10000 / UNK / Unknown / Unknown species / / Unknown species 10001 / UNL / Unlisted / Unlisted species / / Unlisted species (following previous questions here on unknown and unlisted species predefined in the preview in OF collect but not working in OF mobile) I have created a new entry in tree after the tree_species in the OF collect survey and I would like to make it relevant only when expression is verified' with an expression looking like: tree_species = 'Unknown species' However I don't know what expression to write as the tree species is not a single values list but a table with several columns. Any help would be much appreciated! ## Accepted answer (score 0, by Stefano (OF) on 2019-04-01) Link: https://openforis.support/questions/2232/of-collect-survey-entry-relevant-only-for-unknown-and-unlisted-species/2234 Dear Gael, Please try to use the code of the species in the expression that you have to write. For example: tree_species = 'UNK' The expression checks that the user selected the value "UNK" in the tree_species attribute of the same "tree" where the new attribute is defined. Many thanks, Open Foris Team