Question

create raster from lines or TIN

  • 24 August 2018
  • 5 replies
  • 15 views

Hello

I have a shape with lines and one attribute with elevation (NEAU) and an other attribut with classe (RANG).

Between a line and the nearest line it's necessary to create a TIN or raster starting for each line (IDT) from rank 1 to rank n + 1...

And after I create a raster from the TIN.I used a 3d Forcer and TIN Generator but i dont know how to loop on the class for the same line. Thank you


5 replies

Badge +11
Hi @marionmahot,

 

Would you be able explain a little bit more about what you are trying to achieve in your workspace? If you're also able to share your workspace, that might help us generate some more ideas for you. Thanks!

 

 

-Jovita

 

1 - I would like make a loop on the sections of the hydrographic network (IDT field):

? On each section of the river system, making a loop on the cross sections to interpolate a TIN between each profile and its immediate downstream profile (See example figure below, a track is to transform each vertex of the polyline into point with for elevation the value of the field NEAU and to realize a TIN between the two successive profiles)

2 - And Assembly of all surfaces between successive profiles on the current section;

3 - Rasterization of the previous TIN and crossing with the DTM for calculation of the height of water (raster calculator if NEAU> MNT then NEAU - MNT otherwise 0);

4 - Assembly of the previous rasters on all the sections of the system. When there is overlap between two rasters to be assembled, retain the max of the two in terms of NEAU;

5 - The final product is therefore the raster of the water heights resulting from the cross sections.

But i don't how to make the first point with this loop with the class and after to choose the second profile....

Thank you

esrishape2none.fmw

I would likre to make a loop to see the line t1 with class 1 and after line t1 with class2 and create tin between this 2 lines.

Badge +7

Hi @marionmahot, thanks for your question!

 

I'm not sure if I follow the bigger picture, but I may have an idea of how to solve your simple case - the looping problem on RANG.

 

So far I see that in the TINGenerator you have grouped correctly on the IDT attribute. Ideally you would also like to group by something like (RANG,RANG+1) so that a TIN section is computed on each group of consecutive steps.

 

I've constructed a workspace that creates a new attribute that links each consecutive RANG step. So for example, for IDT 1, RANG 1 and RANG 2 will be computed together, and RANG 2 and RANG 3 will be computed together, etc.

Let me know if this solves the problem. No "looping" involved! Just a group by trick.

I've attached the workspace file.

grouprangrangplus1.fmw

Badge +7

Hi @marionmahot, thanks for your question!

 

I'm not sure if I follow the bigger picture, but I may have an idea of how to solve your simple case - the looping problem on RANG.

 

So far I see that in the TINGenerator you have grouped correctly on the IDT attribute. Ideally you would also like to group by something like (RANG,RANG+1) so that a TIN section is computed on each group of consecutive steps.

 

I've constructed a workspace that creates a new attribute that links each consecutive RANG step. So for example, for IDT 1, RANG 1 and RANG 2 will be computed together, and RANG 2 and RANG 3 will be computed together, etc.

Let me know if this solves the problem. No "looping" involved! Just a group by trick.

I've attached the workspace file.

grouprangrangplus1.fmw

@marionmahot please note that in the attached workspace I scaled by a factor or 10 in the 3DForcer (for visual aid). Likely you will want to remove that scaling factor.

 

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