Las2Dem and QGIS Graphic Modeller

[Alex Munro]

Hi all,

I would like to incorporate Las2Dem to a QGIS graphic modeller script im working on, but im having issues. 

I can insert the Las2Dem algorithm but when i try to use the resulting raster, it wont get recognised by the next algorithm, and it errors saying no input. The output raster is selectable from the next algorithm's input drop down, but it wont work.

Is this a limitation of LasTools?

Any advice?

Thanks

Alex

[Jochen Rapidlasso]

Hi Alex,

can you please provide a full sample and description what you are doing so we can reproduce the problem?

Thanks,

Jochen @rapidlasso

[Alex Munro]

Hi Jochen,

For the sake of this example, I just want to run the model script and let me browse to a .las file, convert it to raster, and then load that raster into the project so I can then run other algorithms such as contours etc. 

I can set it up as it should be, and the las2dem conversion works, but the resulting raster doesn't get loaded into the project even though the raster output of las2dem is selectable by the other algorithms.

This initial part of the script works as it should - with a raster tiff file created where I designate, but it's not loaded into the project as a layer. 

When i add algorithms to that, even though I can select the "output raster file" from algorithm "las2dem", it errors out saying no input to the subsequent algorithm.

As you can see from that, the Contour algorithm says it has INPUT: None. I have tried using a "Load layer into Project"  in between the Las2dem and Contour algorithms but then that one errors with no input. 

I have attached the model script. 

Thanks

Alex

[Jorge Delgado García]

Thanks for the info ...

Could you provide the LAS file?

There are a couple of issues I would like to check:
1) A warning appears about excessive precision with an illogical value. Although the warnings are "only warnings", it is necessary to have a certain caution to analyze where they come from.
2) Have you checked if the LAS2DEM result generates any correct result?

Finally, it seems clear that this is a problem of gdal_contour, and not specific to LAStools, have you tried to make contour lines using LAS2iso?

Jorge

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[Alex Munro]

Hi Jorge,

LAS file is attached. 

The LAS2DEM algorithm does correctly create the raster file in the location I specify, but it does not insert it into the project to be then used by other algorithms. It does not matter what the subsequent algorithm is (GDAL Contour etc) it will error citing no input, as the raster is not loaded into the project for it to be used. 

The LASTools are working, Im just wondering how to get their results loaded into the projects via the modeller. 

Thanks

Alex