In short: the crop media transformation tool lets you crop media to a specific size or area of interest (AOI).

Note: for now, crop is only available for geo-referenced images. Support for other image types and video coming soon!

How does the crop tool work?

When you crop a geo-referenced image, you will specify a geo-referenced area of interest (AOI). The new image will be cropped to that specific AOI. Your original image is not changed, so you don't lose those extra pixels.

How to crop an image

Open the Dataset that contains the image(s) you want to crop. Select the image(s) and click Transform, then select Crop.

Note: if you want to crop all images in a Dataset uniformly, you can simply select the entire Dataset from your Datasets table and click "Transform" to apply the crop tool. This isn't useful if your images are from different geographic areas, but can be useful if you have many images of the exact same area.

First, specify a Dataset where you want your new cropped image(s) to end up. You can select the Dataset where the original image already lives, or you can select a new one. It's up to you!

Next, paste in an AOI in GeoJSON format. Most GIS tools support exporting a bounding box or polygon as GeoJSON, but we also recommend using geojson.io if you need to create your own manually.

You only need to paste in the contents of the geometry section. Just make sure you get both the opening and closing brackets { } !

Example:

{
"type": "Polygon",
"coordinates": [
[
[
-122.45018005371094,
37.7761422535397
],
[
-122.38014221191408,
37.7761422535397
],
[
-122.38014221191408,
37.81358124698002
],
[
-122.45018005371094,
37.81358124698002
],
[
-122.45018005371094,
37.7761422535397
]
]
]
}

Click Crop. Your new, cropped image should appear in your target Dataset shortly!

Why and when should I crop an image?

Technically, you can crop any geo-referenced image you have in a Dataset, but that doesn't mean that you'll want to.

Like all of our media transformation tools, cropping is generally meant to help make your images easier to annotate. Since you or other users in your account will need to review the image and label the feature(s) you're looking for, you'll want to format that image to make those features as easy to find as possible.

Cropping a really large image into a smaller, more manageable one can greatly reduce the amount of time you spend annotating. This is because you won't have to pan and zoom over and over again to make sure you've inspected the entire large image. Believe me, this really does make a big difference!

Therefore, the crop tool is only really useful when you have a really big image and what you're looking for is located only in one small part of that image. For instance, if you have a satellite image that covers all of Los Angeles, but you're only interested in looking for boats in the harbor area, you can safely crop out the inland/mountain regions.

That said, cropping is related to our tile tool. Tiling is more useful when you do still want to review and label all parts of a large image, whereas cropping is better for when you want to "rule out" entire areas of an image you know you don't need to review.

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