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vincent

1,956 post(s)
#23-Jun-22 21:03

Hi,

I'm trying to use TileGeomOverlayCount. This does not work. I attached a screenshot. What is wrong ? My 'Field' is INT8 type and filled with 1.

Also, why does it needs a field in the arguments ? The function is to count the number of objects overlaying a pixel, so what does a field have to do with it ?

Thank you for your explanations !

Attachments:
tilegeom.jpg

danb


1,935 post(s)
#23-Jun-22 21:41

Jumped in too quickly. I will give it a go first.

From a quick look, I think this is one of those ones where you need to put them in a map and try and find an alternative transform which joins them and will reproject the image into the same space as the image and then edit and modify the auto generated query to use this function.

I would be very happy to be wrong on this as I have missed this sort of functionality from the transform pane.


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adamw

10,011 post(s)
#24-Jun-22 08:22

TileGeomOverlayCount returns a table (with an image where each pixel tells how many geoms it belongs to). That's why the call does not work as an expression for a field, as shown on the screen. If you want to count the number of pixels covered by each geom, use TileGeomCount -- or just use the Join dialog.

The field argument passed to TileGeomOverlayCount is used to ignore geoms with NULL values in that field. If you don't need to ignore any geoms, you can pass a blank string.

vincent

1,956 post(s)
#24-Jun-22 15:43

Same result Adam : "cannot parse expression". I tried with the following :

''

' '

""

" "

lionel

972 post(s)
#24-Jun-22 18:47

some questions :

-how we can know using the documentation the structure/Schema of the table return by TileGeomOverlayCount(....) <table> ?

-Does a SQL FUNCTION in manifold can return instead <value> 1x1or <table>nxn a list 1xn ( not table with one column but value with a separator beetweeen each value ? )

Attachments:
TileGeom(overlay)Count.png


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