TQL max value in overlay within an area

Ward van Laatum

Hi support,

I am tying to figure out a tql to get the maximum value of a certain grid (in my case Oppervlak maximale waarde) within an given area.

So, in my case this should be the maximum water depth within my area of interest.

I could not figure it out with the tql, so I looked at the API. There is some information to be found about the overlay and also a maxValue and a minValue. But since I want to know what this value is within my area of intrest, this didnt help me.

Perhaps I should use a combo-overlay....

Some help would be appreciated.

RudolfNL

Hi Ward,

could you expand on why you need the maximum water depth? (Or more generically: the maximum grid value within a specified area?)

At this time we do not have this as a built-in facility. The values seen in the API are of course free to use, but only refer to the Project area as a whole and not to a specific area within it. You may be able to approximate the functionality however, with the following building blocks, although I haven't tested this proces yet:

1. The area you are interested in, ensure it's covered by the polygon of an Area, marked with an attribute such as AREA-OF-INTEREST.
2. Add an average overlay with averaging distance 0, aimed at the AREA-OF-INTEREST attribute. This will serve as a "mask".
3. Add a combo overlay with the average overlay A, and your water overlay B, and a formula to the effect of IF(GT(A,0),B,0). This effectively means "only copy the water overlay values if it's within the area of interest.
4. The combo overlay's minimum value will be 0 (or the water overlay's lowest value in the specified area, if it has negative values somewhere), and the maximum value will be the water overlay's highest value in the specified area (or 0, if the water overlay's highest value is negative in the specified area).
5. The minimum and maximum values of the combo overlay can now be obtained via the API.

Can you see if this works for you?

Regards,

Rudolf