Once you have your survey successfully upload to PrecisionMapper you'll need to "Accept or Decline" this survey. Before you accept your survey you should check for general quality in the large preview of the orthomosaic. Once you "Accept" this orthomosaic it will count against any monthly limit you have on your subscription. You must Accept the orthomosaic in order to begin applying any algorithms against the data.
Review of your data can take place in the precisionmapper.com viewer. However you may benefit from reviewing the data outside of precisionmapper.com. You will get some additional zooming capabilities outside of the website in a program like QGIS or Google Earth. Full instructions on viewing outputs in these programs can be found here.
What to Review For?
Throughout this review you are checking for many of the same things that you would look for in our In Field Data Verification article. If you have followed this article along with our Guidelines to a Quality Orthomosaic article you should hopefully not run into any of these issues. However if you do find any of the issues mentioned below it may mean that you are forced to re fly the mission with different flight parameters or conditions.
It is important to understand that re uploading or reprocessing the same data from the user side will yield the same results for each attempt. If you do have issues in your final orthomosaic that you think we can resolve, the PrecisionMapper support team is able to run another version of processing on your imagery upon request (Support@precisionmapper.com).
Ensure that your entire survey area was captured
Gaps or holes-
Check for missing imagery in the middle of your survey area. This does not mean that images were left out from your download, this is a common issue in processing where images were left out because they could not be stitched in by the processor. It is most often caused by homogeneous areas in your survey or improper altitude/overlap used for a survey.
Shadows or change of lighting-
If you see any change of lighting during your survey it will cause shadows and artifacts in the final orthomosaic. This will cause major issues for any algorithms that you run against the data.
Mis-alignment of images-
Look for any mis alignment of the stitched product between flight transects. This can also cause un natural artifacts that will pass into any algorithms you run on the data.
Out of focus images or source data that was taken at a high flight speed may come out blurry. It is typically easier to see this blurriness in the actual source images from a survey but you will see slight effects or issues stitching in your final orthomosaic if you try to use this data.
The lighting in your area of interest at the time of the survey is known to cause this Vignetting effect in some cases. It is one thing to see this effect in the source images, but when you do try to process imagery that has vignetting it will typically have this distinct honey comb look in the worst of cases. We talk about Vignetting a little more fully in our Guidelines to a Quality Orthomosaic article, but this effect is most commonly seen in surveys taken during the solar noon of a region (roughly 11 am-1 pm).