Check out our GCP walkthrough video to see a summary of this article
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:
- Northing,Easting,Elevation (ft)
- Northing,Easting,Elevation (m)
- 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.
GCP CSV Templates:
Northing / Easting Template (ft)
Northing / Easting Template (m)
Latitude / Longitude Template (m)
Custom Coordinates Template (m)*
Custom Coordinates Template (ft)*
Custom Latitude / Longitude Template (m)*
Why is this required?
In order to read your .csv file our software expects it to contain 4 columns for the GCP Label, Latitude/Longitude or Northing/Easting coordinates, and the Elevation (units) for every GCP target. Your column headers will change depending on the type of coordinate system, indicated by your EPSG code, used to measure the GCP locations.
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):
Example page containing PROJCS and UNIT ["US survey foot"]
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):
Example page containing PROJCS and UNIT ["metre"]
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.
Example page containing GEOCS
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):
Step 2. Upload GCP file
Using custom coordinate system?
Our DroneDeploy GCP workflow does support processing and exporting maps with customer coordinates system. Please review our Custom Coordinate Systems support documentation to learn more about it.
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.
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:
To designate a point as a checkpoint, include the word “checkpoint” in the GCP Label column
Add at least 4 quality GCPs!
You can add as many checkpoints as you want, just ensure that you are still using at least 4 non-checkpoints GCP targets.
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.
Example of the Accuracy Report for GCPs and Checkpoints