Results: Unchanged: no computed value and no GeoTIFF or CSV can differ from version 2.2. The tile-engine fingerprint is the same as 2.2, and no file of the area, tile, suite or tree calculations was edited. One kind of exported file gains text: when no exact date is known, the provenance of a single run from a catalog source that has a collection window now holds the members collectionWindow and dateDeclaration. They are in prism-provenance.json, in the analysis bundle's provenance.json and in the copies of that record inside the analysis-suite ZIP. Provenance also records version 2.3 with its build and release date.
For a public USGS source chosen from the catalog, PRISM now shows its collection window: the first and last collection day that the USGS project table records for the source's whole work unit (the project area the source belongs to). The catalog row gives the dates in place of the year. The source metadata, the plan card, the large-area tile dialog and the multiple-date workspace give the sentence, for example “Collected between 2019-12-16 and 2020-01-07 (USGS record)”, or “Collected on 2019-05-14 (USGS record)” when the record gives a single day.
A result from such a source that has no exact date now gives that sentence in Outputs, the Inspector, pixel inspection and the Individual trees dialog, and the map legend gives the dates marked “(USGS record)”. Before, such a result showed “Not specified” or no date.
The window comes from the USGS project table (WESM), retrieved on 2026-11-11 (UTC). It covers the whole work unit: it is not the flight date of your study area, and PRISM does not derive dates from the returns. The multiple-date workspace still needs dates that you have verified.
2,113 of the 2,282 catalog sources have a window. The others are listed as before and give “Not specified” in results, and a source opened by its own address has no window.
When no exact date is known, the exported provenance of a single run from a catalog source that has a window now records the window, the work unit, the rule that joined the source to it and the checksum of the table, with a sentence that says what the window is. The files of a tiled job, of the multiple-date workspace and of the Individual trees dialog do not record it.
Version 2.2
· Research preview
Results: Unchanged: no computed value differs from version 2.1, and exported files differ only in the version, build and release date that provenance records. Only About and the Methods page changed; no processing code was edited, and the tile-engine fingerprint is the same as 2.1.
About and the Methods page now say that the site's host, Cloudflare, keeps anonymous statistics of visits, and list what those statistics hold. No point data, study areas or results leave your browser.
Version 2.1
· Research preview
Results: Unchanged: no computed value differs from version 2.0 for the same study area, data and settings. The area-metric code has the same tile-engine fingerprint as 2.0, no tree, change-map, suite, date-queue or tiled-job calculation changed, and the automated tests pass. Exported files differ only in text: provenance records version 2.1 with its build and release date, and a project still carrying the example's name is renamed New study area when a new area is set, which changes the project name in exports and the ZIP file name.
PRISM now opens the prepared Sumatra hurricane example each time the page is opened. If this browser holds a study area of your own from an earlier visit, a notice above the viewer offers to restore it with its settings, and Project → Restore last study area does the same. Point data and results are not kept in the browser.
The 2D map shows the study area's size with two buttons, Draw new area and Clear area. Draw new area keeps the current area and its results until you press Finish. Clear area asks first when a result computed in this session would be cleared. Both are also in step 1's menu, and in the Data menu and command search as Draw new study area and Clear study area; the Layers panel has a Clear study area button. While a plan is being read or an analysis is running, the map, the Data menu and the Layers panel refuse them and give the reason.
New project and Clear area now leave no study area. The example's square is no longer carried over, the map shows no outline, and the run, plan and export controls say that a study area is needed until you draw or import one.
The Use N m cells instead button is removed from step 2. Cell size is changed only under Advanced options; where a larger cell size would let the area fit one run, the step 2 note names that cell size. Changing the cell size says whether the area then fits one run or needs tiles.
In the numbered strip the next step's number is filled, step 1 names a study area of your own with its size, and the lines under steps 2 to 5 follow the route: one run, tiles, or an area that cannot be processed. Step 3 also names a local file.
A study area can be drawn from the keyboard. With the map focused, the arrow keys move the map, Enter adds a corner at the centre mark and Backspace removes the last corner. From the third corner the draw bar shows the area, and says when it needs tiles or is over the limits.
Keyboard focus follows the work: to the step 2 note after Finish or an import, to the units tick when a plan arrives, and to the result when a run completes. Menus can be moved through with the arrow keys, two skip links lead to the numbered steps and the Workspace panel, and command search matches more words and runs the first match on Enter.
On a phone the Workspace and Inspector panels open in front of the map, menus stay within the screen, messages appear at the top of the screen, the Methods page fits the screen width, and the manual's contents open from one button.
The source list follows the step 2 note and any plan or stop card, and Use this source is each row's main button. The plan card keeps the units tick and Run analysis in view and states the limits on candidate and accepted returns.
Map legends and pixel inspection state each product's unit, and clicking a computed product on the map shows that cell's value. Outputs lists the settings used, the number of cells with returns and the grid's coordinate reference; the Inspector lists the settings and the coordinate references of the source and of the analysis grid.
The large-area tile dialog states the cell size, the fixed output grid and the files a tiled job writes, and says that statistics are per tile, with no whole-area summary or whole-area percentiles.
When the analysis suite finishes, a message gives the number of canopy peaks found, or says that there is no tree result, and the result summary lists every change grid by product name. In the Individual trees dialog the preview can be magnified two or three times.
Contrast is higher for viewer tabs, the status bar, focus rings on filled buttons, crown-footprint ID colours and the low end of the point view's elevation colours. These are display colours only.
In About the date is now labelled This version released. From this version on, each new release has its own version number, release date and release note, and each note says whether results can differ from the version before it.
Version 2.0
· Research preview
Updated
Analyze public USGS 3DEP data within a drawn or imported study area, with terrain, canopy, height, cover and return-density outputs.
Explore the prepared Sumatra acquisitions, dated differences, canopy peaks and crown regions. Export results with source and processing records.
Fixed public-source downloads that failed with an Illegal invocation error in browser workers.
Drawing a new polygon now opens the source choices and clears results from the previous area. Download errors remain visible with a retry action.
Clarified the five-step workflow, source dates, tree settings, change-map legends and saving versus exporting.
Added release notes and a workflow manual with screenshots of the actual app.
The workspace and the overview, methods, release-notes and manual pages now use a dark colour scheme for every visitor, whatever the browser's own setting. The manual, overview and methods pages still print as dark text on white.
Condensed the top of the workspace on wide windows: menus and tools share one row, the five numbered steps are one line with their status beside them, and the viewer tabs share a row with the example controls. Every control is still there; the map and point viewer gain about a hundred pixels of height.
After you draw or import a study area, and again when you change the cell size, PRISM now states in step 2 whether the area fits one run or needs tiles, and Use this source opens the large-area tile dialog with that source selected when tiles are needed; tiled results are files in a folder you choose and do not open in the map.
Release & attribution
Cite PRISM
Record the software version alongside the original acquisition, method definitions and analysis settings.
Broadbent, E. N., Drake, J. B., Medley, P., & Almeyda Zambrano, A. M. (2026). PRISM: A browser-based, cross-platform environment for LiDAR and remote-sensing analysis (Version 2.3) [Computer software]. https://prismlidar.app
Developed with support from the Apalachicola Regional Restoration Initiative (ARRI) and the Partnership for Remote Inventory and Stand Management (PRISM) of the U.S. Department of Agriculture, Forest Service and SPECLab internal research funds. Portions of the software development and documentation were completed with assistance from AI tools under the direction of the PRISM development team. The team is responsible for reviewing and verifying these contributions. Validation status and remaining limits are described in the Methods. Development continues with support through ARRI and SPECLab internal research funds.
