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Kshitij Raj Sharma
Kshitij Raj Sharma

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Working with open imagery of the world ? : OpenAerialMap

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Introduction

URL : https://openaerialmap.org

Description : OpenAerialMap is an open service to provide access to a commons of openly licensed imagery and map layer services. Download or contribute imagery to the growing commons of openly licensed imagery. This short tutorial will document the steps needed to process and publish your images in OpenAerialMap

How to upload images ? :

1) Go to openaerialmap
2) Sign in using your google account
3) To upload your image : Hit Upload
4) Provide metadata for your image ( Type of sensor used , License , Creator and etc )
5) Submit , Grab Tea and Wait for the completion
6) Once upload is done you can leave the browser , OAM will do its own postprocessing step and email you when it is done
7) Once image is available in OAM you can share it with your network , Grab it as TMS/ WMTS in your QGIS , Perform mapping using this imagery . Opportunities are unlimited

Troubleshooting

Currently , OpenAerialMap doesn't support more than 4 bands . if your image has more than 4 bands then you need to remove extra bands in order to upload in OAM

Removing extra bands ( Adopt 4 bands limit of OpenAerialMap)

To remove bands / only extract related bands in your image :

For us , We had 6 band image hence we needed to do some preprocessing using QGIS

  • Reaarange Bands ( GDAL utility )

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In QGIS search and find Reaarange bands under GDAL . This function allows you to choose and extract specific bands from
the image and create new tiff with it . We created two orthophotos

  1. Orthophoto with R, G, B and NIR band
  2. Orthophoto with only RGB band

Exporting tiff as rendered image ( fix no display problem / Not rendering issue )

By default with exporting only RGB band as Raw we encountered following issue in OAM ( Image not being rendered ) and not only in OAM its not rendering in ID editor , JOSM and QGIS .
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  • Hence to solve this problem , we exported our RGB tiff as rendered image in QGIS image

Black background for nodata problem

Since we used our area of interest to create this orthophoto as there will be pixels with no data in it and by result its being displayed as black in OpenAerialMap and all other places
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  • Hence to solve this problem we clipped our rendrered exported tiff with our Area of Interest in QGIS , ( We had to clip specifically the rendered image output instead of RAW to avoid this problem ) image

Finally , Now you can upload your rendered clip RGB image to OpenAerialMap.

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Resources and Credits

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