GCPs load, but in the wrong place

I believe this must be a formatting issue. I’ve only ever had partial success with GCPs. Please let me know what I’m missing in my .txt file.

Thanks!

GCP Interface issue|690x392

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Welcome!

Sorry you’re having a bit of trouble with your GCPs.

Are you able to provide the text for them here as well?

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EPSG:4326

42.71569216203569	-72.44409890359766	65.16426547619042	a
42.71596591772522	-72.44418250470855	64.03324834437083	b
42.71562223124421	-72.44383059701983	67.65279009900988	c
42.71548601562463	-72.4435629668339	66.79212624584716	d
42.71597845746121	-72.4435404530382	67.73976805721098	e
42.71561768033766	-72.44335798582148	68.76945980707391	f
42.715503582862304	-72.44309400641902	69.75195741998057	g
42.715212639877876	-72.44323520583497	71.45065346534656	h
42.71521555789183	-72.44297180936722	79.03381672131147	i
42.71546956301539	-72.4426360418615	75.73504892307693	j
42.71514302364149	-72.44259130646049	77.74934078947369	k
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These are coordinates I gathered using an Emlid Reach rs+. The original export was a .csv file (which ODM does not read). So I manually created the above .txt file and tried to use the proper formatting.

My other attempt with GCPs used the same format but with a different issue: the GCPs that loaded were in the correct spot, however only 3/6 were pulled from the list and rendered on the map.

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Thanks for providing that!

We’ll get this one sorted and figure out what’s wrong, then I’ll try to help you with the one that dropped entries :slight_smile:

Does this location look correct? Let me know and I’ll post my corrected version.
image

If so, it was an issue with the state of your GCP data. It wasn’t complete/well-formed to be a gcp_list.txt yet, but was sufficient to be formatted as a CSV file for import/resume. To be a gcp_list.txt it will need the image_x, image_y, and image_name columns/values to be valid, which this does not have yet.

Check the docs here:
https://docs.opendronemap.org/gcp/#gcp-file-format

Yes, those are the correct locations.

How do I get the image_x,y, and name values before generating the GCP targets on the map? Don’t those values get generated only after each GCP has been linked to 5+images? Or am I missing a step?

I thought the workflow went:

Collect GCP field data
Collect drone images
Convert GCP export (csv, shapefile, GeoJSON) into “gcp_list.txt” (without image_x,y,name values)
load gcp_list.txt into GCP Interface box1
load drone images into GCP Interface box2
Manually ‘tie’ GCP targets on map to visible GCPs in drone images (5+images per GCP)
“Export File” from GCP Interface (now includes image_x,y,name values of manually selected GCPs).

Then my assumption (although I have yet to reach this step) is:

upload drone images AND newly exported GCP file into a new project (from dashboard) before setting parameters

I could use some help clarifying this workflow. :sweat_smile:

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GCP Label,Y,X,Z
a, 42.71569216203569, -72.44409890359766, 65.16426547619042
b, 42.71596591772522, -72.44418250470855, 64.03324834437083
c, 42.71562223124421, -72.44383059701983, 67.65279009900988
d, 42.7154860156246, -72.4435629668339, 66.79212624584716
e, 42.71597845746121, -72.4435404530382, 67.73976805721098
f, 42.71561768033766, -72.44335798582148, 68.76945980707391
g, 42.71550358286230, -72.44309400641902, 69.75195741998057
h, 42.715212639877876, -72.44323520583497, 71.45065346534656
i, 42.71521555789183, -72.44297180936722, 79.03381672131147
j, 42.71546956301539, -72.4426360418615, 75.73504892307693
k, 42.71514302364149, -72.44259130646049, 77.74934078947369

So, with the field-collected GCP/GPS data, you only really have enough to form a proper gcp.csv, the format/structure of which is clarified in the docs:
https://docs.opendronemap.org/gcp/#gcp-file-format

From there, you’d load it into POSM GCPI or GCP Editor Pro as a CSV to then tag the images and the image x/y locations which are mandatory for a properly formed gcp_list.txt

So, not terribly different from how you understood the workflow, but just that you have to start with the gcp.csv when you start from the GPS data.

A post was split to a new topic: How to put gcp_list.txt in Project File