[OSGeo Africa] South African NGI 25cm Imagery available online

[Grant Slater]

Hi OSGeo Africa,

Since 2017, the South African National Geo-spatial Information (NGI)
has been capturing and making available aerial imagery at an
impressive 25cm resolution. NGI is nearing the completion of capturing
the entire country at this resolution. More details can be found here:
https://ngi.dalrrd.gov.za/index.php/what-we-do/aerial-photography-and-imagery/35-colour-digital-aerial-imagery-at-0-5m-gsd-2008-2016-and-0-25m-gsd-2017-current

Through multiple trips to the NGI office in Cape Town, I, along with
others, have collected copies of this imagery. To help with this task,
I had to purchase a 22TB external drive.

I have now processed the imagery and made it available online:

https://aerial.openstreetmap.org.za/

For further discussion about the imagery, visit: OpenStreetMap Community:
https://community.openstreetmap.org/t/new-25cm-aerial-photos-available-from-chief-directorate-national-geo-spatial-information-cd-ngi/8452/28

QGIS Users:
Here are notes on how to use the imagery in QGIS:
https://kartoza.com/blog/qgis/how-to-easily-add-south-african-and-namibian-toposheets-as-xyz-tiles-to-qgis
Use this URL: https://aerial.openstreetmap.org.za/layer/ngi-aerial/{z}/{x}/{y}.jpg
(TMS top-left origin)

Fun Facts:
* Number of source image files: 44,305 (more when 25cm coverage is completed)
* Cost of 22TB external disk: R8900 (on promotion)
* Source imagery projection: Transverse Mercator Lo17 to Lo33
* Source size: 13,264GB
* Time for conversion to Cloud Optimised GeoTIFF (COG): 55+ days
* COGs with WEBP compression (as used by site): 2,442GB
* Total pixels: Over 21 billion (21,000,000+ megapixels)
* Software stack: gdal, titiler, nginx, podman

Support / Donations:
Hosting is kindly supported by the OpenStreetMap.org project and
INX-ZA. Donations to support other expenses would be greatly
appreciated.
Donate via PayPal: https://paypal.me/firefishy
FNB banking account details: Available on request

A huge thank you to National Geo-spatial Information (NGI) and the
Department of Agriculture, Land Reform and Rural Development (DALRRD)
for providing this fantastic aerial imagery. Special thanks to Adrian,
Glenn, and Zander for their help with the logistics.

Kind regards,

Grant