Coordinate systems, GCP files and State Plane downloads

SkyPLX-9 makes your map in WGS 84 / UTM metres, or in WGS 84 degrees (EPSG:4326) if you picked that under “Coordinate system” in step 7. State Plane isn’t a processing choice: you get it afterwards, as a download made from the finished map. Your original files are not changed.

Downloading your map in State Plane

1. Office › Work › Field › DSP · /office/work/field/dsp, then the folder, then the project.
2. On the mission’s card, open the “⋯” menu and click “Open the map page”. (“Open the map” opens the map viewer, which has no State Plane download.)
3. In the “Download deliverables” box, click “Download in State Plane”. With the newer themes it is also under “More” at the top of the page (and the “Deliverables” tab takes you to the box); with the Classic theme it is also in the left-hand column.
4. Pick your zone under “State Plane zone (NAD83(2011))” (type to filter, e.g. Colorado or 6428), then the “Units” and “Heights”.
5. Answer “What are this map’s positions based on?”. It sets the accuracy your download states; it does not move the map.
6. Tick the “Files” you want and click “Make my download”.

You can close the window: the files keep being made and appear under “Recent State Plane downloads”. Each download is kept for 7 days.

Why the button is greyed out

Until the map has finished processing, “Download in State Plane” shows greyed out with “Available once the map is finished processing”. Come back when step 7 says “Map ready”. If your plan doesn’t include State Plane downloads, the window says so and offers “See plans”.

What your GCP file needs

One row per GCP: a name, then easting/northing (or latitude/longitude), then elevation. Put the column names in the first row: names like Name or Point, Northing and Easting (or N/E, X/Y), Latitude and Longitude, and Elevation, Height or Z are recognised. Commas, semicolons or tabs all work.

Name,Northing,Easting,Elevation
GCP1,1701234.56,3141234.56,5280.12
GCP2,1701534.10,3141890.22,5279.40

Don’t put the EPSG code in a CSV. Upload the photos first; then the Guided GCP setup (“Add ground control” on the mission’s card) tries the coordinate systems that cover your site and recommends the one that puts your points on your photos. To use another, open “Advanced: change anything”, type it in “Use this EPSG code instead” and click “Check”. A gcp_list.txt is different: its first line is the coordinate system, e.g. EPSG:6428.

Common questions

My GCP CSV was rejected. Why? “Could not find coordinate columns” means none of the column names was recognised: rename them as above. A file with latitude/longitude needs a degrees system such as EPSG:4326 (WGS 84) or EPSG:4269 (NAD83), not a State Plane code.

My file has no column names. Is that OK? Usually. It is read as point, northing, easting, elevation (PNEZD), or name, latitude, longitude, elevation for degrees. If yours has easting first, add a header row so the columns aren’t swapped.

Which height reference do I pick? Under “Height reference of your GCP elevations”: NAVD88 for a normal US surveyor export, Ellipsoidal for raw GPS heights. See GCP & PPK Accuracy.

Does the orthomosaic lose quality? Left unticked, “Lossless (larger file)” saves a smaller JPEG copy that looks the same; tick it to keep every pixel. Elevation files are always lossless.