# Common questions

> Photos and overlap, GPS and RTK, how long a run takes, why one failed, paying from outside Chile, invoices and your data.

Page: https://cloudodm.stellaris.cl/learn/questions

## How should I fly?

Overlap matters more than anything else: aim for at least 70% forward and 60% side overlap, more over trees, water or bare ground, where photographs look alike. Fly at a constant height above the ground, keep the camera's settings fixed, and avoid hard midday shadows when you can. For 3D models of buildings, add a pass with the camera tilted.

## GPS, RTK and ground control

Photographs with GPS place the result on the map by themselves. With RTK or PPK positions the accuracy the drone measured is used, and the run warns you when the model and the positions disagree. For survey-grade results, add ground control points.

To measure the accuracy of your own survey, hold some surveyed points back as checkpoints: in the ground-control file (gcp_list.txt), give them a name that starts with CHK. They are left out of the adjustment, and the run reports the error at each one, on the results page and as a PDF you can hand over. A file with checkpoints only works too, which is the usual check of an RTK flight flown without control. Where runs are sold as Basic and Premium, the report is part of Premium.

## How long does a run take?

It depends on the number of photographs and the detail you ask for, and the composer shows its estimate for each stage before you start. Premium runs on the fastest machines available and goes first; Basic waits behind it on more economical machines. The run's page shows each stage as it goes.

## A run failed. What now?

A failed run costs nothing, and any hold on your card is released. The run's page says what went wrong in plain words — most often too little overlap, photographs without position, or a flight that does not join into one block — and what to change. If it is not clear, write to us from the contact page with the run's name.

## Paying from outside Chile

Card payments through Transbank need a Chilean card. From anywhere else, pay with PayPal — an international card or a PayPal account, in US dollars — either for a run before you start it, or to add balance in Billing.

## Boletas and facturas

We issue your boleta, or your factura if your organisation has a RUT on file, with the SII after you pay. If you need a factura, send us your organisation's RUT and business details from the contact page before paying. Prices include IVA where it applies.

## Your data

Your photographs and results are yours: we process them only to do the work you ordered, never use them to train anything, and delete results when the hosting time you chose runs out. Where data is processed, and how to see or delete what we hold about you, is in the terms.

Anything not answered here: the contact page reaches a person, usually within one working day.

## More about CloudODM

- [CloudODM: photogrammetry and LiDAR in the cloud](https://cloudodm.stellaris.cl/)
- [Cloud photogrammetry](https://cloudodm.stellaris.cl/fotogrametria-en-la-nube)
- [LiDAR classification](https://cloudodm.stellaris.cl/clasificacion-lidar)
- [Point cloud viewer](https://cloudodm.stellaris.cl/visor-nube-de-puntos)
- [Pricing](https://cloudodm.stellaris.cl/pricing)
- [Features](https://cloudodm.stellaris.cl/features)
- [Measured accuracy](https://cloudodm.stellaris.cl/accuracy)
- [Demonstration: a finished survey](https://cloudodm.stellaris.cl/demo)
- [How it works](https://cloudodm.stellaris.cl/how)
- [Tutorials](https://cloudodm.stellaris.cl/learn)
- [ODMDisplay, the desktop application](https://cloudodm.stellaris.cl/viewer)
- [Contact](https://cloudodm.stellaris.cl/contact)
- [Terms and privacy](https://cloudodm.stellaris.cl/terms)