Kestrel

A sharp eye on your geospatial data.

We've all had this moment: you drag a layer into QGIS and… nothing. No error, no shape on the map — just empty space. Kestrel tells you why.

Drop a file on it and it reads back the CRS / UTM zone, the data's real-world location, and a plain-English list of anything that would stop it from drawing. A quick, friendly sanity check for the everyday "wait, where did my layer go?" — and it never changes your data, it just takes a careful look.

What it tells you

• Format & driver (Shapefile, GeoPackage, GeoJSON, GeoTIFF, …)
• CRS — name, EPSG code, UTM zone, projected vs. geographic, units, datum, and the region the CRS is valid for
• Location (WGS84) — the extent reprojected to lon/lat, so you can confirm the data lands where you expect on Earth
• Map preview — a globe showing where on Earth the data sits, next to a zoomed view of the extent. Offline by default (coastlines, lakes, borders and town names, so it works with no network at all); flick on Satellite for Esri World Imagery and zoom right in on the field. No API key, and it falls back to the offline map if there's no connection.
• Details — geometry type, feature count and fields (vector); size, bands, data type, pixel size and NoData (raster); native extent
• Diagnostics — common reasons a layer won't show up in QGIS:
  • No CRS defined / missing .prj
  • Coordinates that don't match the declared CRS (e.g. lat/lon tagged as a projected CRS — the classic "lands in the ocean")
  • Empty layers, zero-area extents, "Null Island" (0, 0) coordinates
  • Data outside the CRS's valid area, the wrong UTM hemisphere/zone, or an extent that wraps the antimeridian
  • Invalid / self-intersecting geometry, and layers in mismatched coordinate systems
  • Multiple layers in a GeoPackage (you may be loading the wrong one)

…and now it can fix them

Spotting the problem is half the job. Kestrel can repair the common ones for you:

Fix	What it does
Set the CRS	Tags a file with the coordinate system it's really in. Coordinates are not moved.
Reproject	Transforms the coordinates into another CRS.
Fix geometry	Repairs self-intersections and invalid rings.
Convert	Writes the data out as GeoPackage, Shapefile or GeoJSON.
Table → points	Turns a CSV/Excel coordinate table into a real point layer.

Your original file is never modified. Every repair writes a new file into an output folder you choose, and Kestrel shows you exactly what it's going to do before it writes anything — then re-reads the result and tells you what it actually produced.

When a file has no CRS, Kestrel suggests likely candidates. Coordinates alone can't identify a UTM zone — the same easting/northing is valid in all 60 — so it draws on context: other files in the same folder that do declare a CRS, and the ones you've picked before. For the usual case (one file in a delivery lost its .prj) that's often the exactly-right answer. You can also type an EPSG code or search the EPSG database by name.

ArcGIS services and layer files

Paste an ArcGIS REST URL (Open URL…) — a FeatureServer or MapServer, optionally with a layer index — and Kestrel reads it like any other layer: CRS, real-world location, geometry type, fields and a map preview of the actual features. Nothing is uploaded; it only issues GET requests to the URL you give it.

It also checks something you can't see from the service page: whether the published extent matches the data. Clients use that extent for Zoom to Layer, so a stale one sends everyone to the wrong place.

.pitemx portal-item files are followed straight through to the service they point at.

ArcGIS Pro layer files

Drop a .lyrx (or .mapx) on Kestrel and it follows the layer to its data. Layer files don't contain data — they point at it — so the useful questions are different:

• Is the data still there? A broken link is the red exclamation mark in ArcGIS Pro, and the most common reason a layer draws nothing.
• Is it pointing at a scratch geodatabase? Pro writes new features into a temporary Default.gdb unless you tell it otherwise, and that folder gets cleaned up — so the layer works today and is broken next week. Kestrel calls this out specifically.
• Is a definition query hiding features? The data is there, the layer is filtering it.

When the source resolves, Kestrel inspects it normally, so you also get the real CRS, extent and map preview of the data behind the layer.

ArcMap's older binary .lyr isn't supported — it's an undocumented proprietary format that needs Esri's own libraries to read.

Audit a whole folder

Drop a folder on Kestrel (or use Audit folder…) and it checks every dataset inside — one row per dataset, worst problems first, sortable, with Export CSV / HTML. That answers the question that actually costs time: which of these 400 files is going to be a problem? Useful before a delivery goes out, or right after one arrives.

From the command line:

py cli.py --batch path\to\folder --html audit.html --csv audit.csv
py cli.py --json path\to\file.gpkg        REM machine-readable, for pipelines

Exit code is 1 if anything has an error, so it drops straight into a CI check.

Supported inputs

Zipped or plain shapefiles, GeoPackage (multi-layer), File Geodatabase (.gdb — just drop the folder), GeoJSON, KML/KMZ/GML/GPX, DXF (CAD), FlatGeobuf, TopoJSON, OSM, MapInfo, PMTiles/MVT, CSV / Excel including the old .xls (it finds the lon/lat or x/y and infers the CRS), LAS / LAZ point clouds (header-only, so it's instant on huge clouds), and rasters via rasterio (GeoTIFF, IMG, VRT, JPEG2000, …). Unknown extensions are tried as vector first, then raster, so most things just work.

User guide

A full User Guide (Word, 27 pages) covers everything from installing to every feature, with screenshots and a complete reference for all ~48 checks. It's a .docx so you can edit it for your own team before handing it round.

Regenerate it after a UI change with:

py docs/make_screenshots.py    REM refresh the screenshots
node docs/build_userguide.js   REM rebuild the document

Getting it

Download (recommended)

Get it from the Kestrel website, or straight from the Releases page (no Python required):

• KestrelSetup.exe — installer (recommended): per-user, no admin needed; adds a Start-Menu shortcut and an uninstaller.
• Kestrel-windows.zip — portable: unzip anywhere and run Kestrel\Kestrel.exe.

It's a one-folder build, so it starts fast (about a second) after the first launch. The app is unsigned, so Windows SmartScreen may warn on first launch — choose More info → Run anyway.

The installer also adds a right-click → "Inspect with Kestrel" entry for geospatial files (on Windows 11 it's under Show more options). Portable/zip users can enable it once with Kestrel.exe --register (and remove it with --unregister).

Run from source

• GUI: double-click run.bat, or run py gui.py. (Right-click run.bat → Send to → Desktop to make a desktop shortcut.)
• Command line: py cli.py path\to\data.gpkg prints the same report in the terminal.

Needs Python 3.10+ and the packages in requirements.txt:

py -m pip install -r requirements.txt

Build the .exe yourself

py -m pip install pyinstaller pyinstaller-hooks-contrib
build.bat            REM  ->  dist\Kestrel\Kestrel.exe   (one-folder app)
build_installer.bat  REM  ->  dist\KestrelSetup.exe      (needs Inno Setup 6)

The build recipe is Kestrel.spec (bundles the GDAL/PROJ data) and the installer script is Kestrel.iss.

License

MIT © 2026 Dozer3530