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Your image
Start with an image
A photo, a scan or a satellite frame. It stays on your computer.
Most image formats, plus
TIFF, JP2 and PDFi
JPEG, PNG, WebP, GIF and BMP are decoded by the
browser. TIFF, GeoTIFF, JPEG 2000 and PDF are not —
those use geotiff.js, an openjpeg build and pdf.js, each fetched only
when a file needs it. A big TIFF is read downsampled, so its size
costs little. A GeoTIFF that already knows where it is says so.
Your images never leave this machine.i
They are read into a canvas and matched on your own
GPU, which is also why there is no server bill behind this page.
Fetching a reference sends the area you chose — not the
image — so the right tiles come back. Choosing your own reference
sends nothing at all.
, reduced to 1024 px for matching.
, reduced to 1024 px for matching.
Or try an example
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Where is it?
Where is it?
Search for a place, or drag on the map to draw a box round what the image shows.
Drag on the map to draw a box.
No place needed?
A printed sheet with its own frame or
your own reference image skip this step.
Type coordinates instead
Draw the box
round what the image showsi
Not the region it sits in. A reference much coarser
than the image stops matching: measured on one scan, a reference
3.4× coarser gave 2 matches where 1.3× gave 180. If it
finds nothing it halves the area once and tries again.
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Reference
What should it compare with?
A current picture of the same place. The tool finds the same features in both.
About Sentinel-2i
Free to use commercially, which the sharper
basemaps are not: Esri restricts commercial use and EOX's cloudless
mosaic is non-commercial. Expect weaker matches than against
sub-metre imagery — a 10 m reference cannot resolve what a
2 m photograph shows.
A rendered map against OSM gave 134
inliers here and recovered the rotation to 0.04°; a
photograph against OSM gave 2 and got it 59° wrong. Both
sides being line work is the reason.
A 19th-century engraved plate is a different matter. Tested against a National Library of Australia sheet: 2 inliers, and land/sea masking did not rescue it. Modern renderings match; antique engraving does not, yet.
A 19th-century engraved plate is a different matter. Tested against a National Library of Australia sheet: 2 inliers, and land/sea masking did not rescue it. Modern renderings match; antique engraving does not, yet.
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