We invest a huge amount of time and care into your data and do our best to process it successfully, however, sometimes the data is uploaded in such a way that makes it difficult to get adequate results from. To ensure that we can turnaround data in the most timely fashion and to avoid any disappointment for both yourself and your clients, it’s worth keeping the following things in mind. Just a few minutes of reading could save you a lot of time and potential irritation!

Sadly, we cannot process data if:

The images are not geotagged. There are some software solutions that can be used to rectify this at your end, but the best thing to do is ensure that the camera is setup correctly for geotagging.

The geotags have severe errors. Some examples include all images geotagged in the same location, all the images are geotagged with the ground height or the geotags have inverted lat/long values.

There is insufficient overlap between images. All images should have at least 70% frontal and 60% side overlap to enable us to process.

There are less than 20 photos for a survey dataset.

There are less than 10 photos for an inspection dataset

GCPs are provided with a local site calibration. The coordinate system of GCP data should have either an EPSG code or a valid definition in a PRJ file.

Unfortunately, processing of data will likely be delayed if:

GCPs are provided but the coordinate system and height datum that they were recorded in is not specified.

Only a portion of the images have geotags.

The images are blurred.

Processing will be much easier if the images uploaded are clear like the one on the right!

The survey images are of an extremely high-density vegetation area.

Please note that data is likely to display incorrectly if:

The image EXIF data offers negative altitude. This will result in the outputs displaying with negative heights. (It is possible for legitimate negative geotags to occur, but this is unlikely unless flying below sea-level.)

The Dead Sea is the lowest point in the world, some 423m (1,407ft) below sea level

A camera has been poorly calibrated. You can read some great optimization tips on setting up a camera here.

Helping us use ground control info for processing

The number-one way to get great, accurate ground control information that makes processing affordable is to use AeroPoints.

Where you are supplying your own ground control point information, please send it to data@propelleraero.com in the following way to optimize the speed at which it can be processed.

  1. CSV is the preferred format.
  2. We need the following information for each point; ID (number), latitude, longitude, altitude, and a description. This information will differ slightly depending on the coordinates system used for collection. Example:

For a geocentric coordinate system:

Please note that decimal coordinates for lat/long are preferred to degrees.

For a projected coordinate system:

3. Please specify the coordinate system that the points are collected in. Currently, we only support global geocentric coordinates like WGS84 or most of the standard state projections, particularly these with EPSG standard. Unfortunately, we don’t support arbitrary defined coordinate system from site calibrated results. Example you could give us:

The GCPs are in WGS84 coordinate on the EGM96 geoid (EPSG 4326);

The GCPs are in MGA Zone 54 and AHD height (EPSG 28356);

I only know that it’s in Colorado State Plane North, and the height datum is NAVD88, All the measurements are in US feet not in International feet;

The coordinate are in NAD83, while the heights are in feet on NAD83 ellipsoid height.

4. Provide some photos of the ground control points, particularly if they are unusual in appearance:

Taking the time to provide us with these four things will be a massive help in us getting your data turned around as quickly as possible.

We understand that data can at times be tricky, and so that’s why we’re here to help as much as possible and take the guesswork and confusion out of the whole process.

Please don’t hesitate to contact us at support@propelleraero.com.au should you have any additional questions or put a question below in the chat.

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