Check out our GCP walkthrough video to see a summary of this article
Our Workflow Requires your GCP Data in a Specific Format
|1. Your .csv file must contain 4 columns|
|2. Your 1st column header must be "GCP Label"|
|3. Your 2nd, 3rd, & 4th column headers must be:
* Latitude,Longitude,Elevation (m)
|4. No cells can be left blank|
|5. The "GCP Label" column must be in numerical order starting at 1.|
|6. You can not have duplicate GCP Labels|
|7. Your GCPs must be located within the bounds of your EPSG code|
|8. The CSV file should be saved using a newer version of Excel or an Excel alternative. Older versions of Excel often cause header row errors.|
If you are having problems with your .csv formatting we strongly recommend you using the correct .csv format templates by following these steps:
1. Copy this URL and paste it into your Address Bar: http://spatialreference.org/ref/epsg/EPSG_CODE/prettywkt/
2. In the URL replace "EPSG_CODE" with your EPSG code value and press enter
3a. If the page begins with "PROJCS" and contains the parameter "UNIT ["foot"]" or "UNIT ["US survey foot"]", download the GCP File template for
Northing / Easting Template (ft) (see example):
3b. If the page begins with "PROJCS" and contains the parameter "UNIT ["metre"]", download the GCP File template for
Northing / Easting Template (m) (see example):
3c. If the page begins with "GEOCS", download the GCP File template for
Latitude / Longitude Template (m) (see example below). Please note that, in this case, the Latitude and Longitud, must be provided in decimal degrees not degrees-minutes-seconds and the elevation must be in meters.
4. Open the downloaded template file in Excel or Numbers
5. Copy and paste your GCP data into the template and make sure your data is in the same order as the column headers
6. Delete any extra rows or columns
7. Go "File", "Save As", select "Comma Separated Values (.csv)" under "File Format:", and click save
8. During the uploading process, select this new .csv in the "Upload GCP file" step (see below):
Are you still stuck?
You may not be using the correct ESPG code. Check with your surveyor to see what EPSG code was used when measuring your GCP locations. DroneDeploy will always assume the elevation values are in feet unless the coordinate system referred to by the EPSG code is also in feet (and not meters or degrees). Please ensure the units of measure in your CSV file match the selected EPSG code.
Adding checkpoints helps you to validate the relative and absolute accuracy of your GCP maps.
To add checkpoints simply make sure that the name of the GCP target in the CSV file contains the word
checkpoint as shown below:
Once the processing is complete, you can analyze the accuracy of your map, including GCPs and checkpoints, by using the Accuracy Report app that is available in our App Market.