Support for logical operators in expressions

[zacdezgeo]

Hello,

I was wondering if there was any detailed documentation about the supported operators for the expression query parameter. I found this interesting article that points to the use of numexpr.

More specifically I was wondering if logical operators were supported. I have been trying to have the following expression evaluated:

(B1>100&B1<150)*B1

After urlencoding:

(B1%3E100%26B1%3C150)*B1

Have there been any related discussions or are there any more docs on the issue?

Thanks for your help

[zacdezgeo]

Found the solution for logical operators, every condition must be encapsulated by parentheses: ((B1>50)%26(B1<150))*B1

Are there any other cool expression features commonly used? Is there some way to integrate non pixel by pixel expressions? Example: calculating the mean of direct neighbors (3x3 window)

[vincentsarago]

@zacharyDez glad you found out the fix.

Usually I use expression just to get simple indexes like NDVI but doing more complex operations is def under my radar. I dream about being about to do the same a sentinel-hub ;-) but for now we are limited to what numexpr can do for us.

Example: calculating the mean of direct neighbors (3x3 window)

for this you could use the post_process option (https://github.com/cogeotiff/rio-tiler/blob/master/rio_tiler/reader.py#L35-L37, https://github.com/cogeotiff/rio-tiler-pds/blob/master/rio_tiler_pds/landsat/aws/landsat8.py#L73-L80)

[zacdezgeo]

Thanks for pointing me in the right direction!