Areas from slope categories in Slope Analysis tool

[unearthed]

Hi all

 

I've just started with the Slope Analysis tool Gridded view, reasonably happy with graphics, but how do I (is it even possible) get the areas of each slope category? I know the info is there as I can explode the model and use the wand to get the areas (by fill colour). Has anyone done this / is there a automatic workflow?

 

VW2018

[Benson Shaw]

I think what you want is Tools>Reports>Create Report>Preformatted Report>Site Slope Analysis

 

It provides projected and surface areas per color.

 

Although I my test starts with some rather unlikely results (huge projected, zero surface????), so I need to suss out the reasons.

 

-B

 

[unearthed]

Thanks for having a go Benson!. I get the same; a vast Projected Area, zero Surface Area  - my actual area is 27 Hectares.

 

I have 5 slope categories.

 

Also it's showing projected area as 54.0791 Ha - I've stripped drawing right back and purged, but still has 54 Ha, not quite double the actual area.

 

Also projected area appears to be square milimetres !

[Katarina Ollikainen]

I've filed a Jira on this so the developers will take a look at what's happening here.

 

[Benson Shaw]

Thanks, Katarina!

Here is my test file, if that helps.

 

-B

SlopeAnalysis.vwx

[unearthed]

On 11/24/2021 at 7:19 AM, Benson Shaw said:

Thanks, Katarina!

Here is my test file, if that helps.

 

-B

SlopeAnalysis.vwx 248.52 kB · 0 downloads

Thanks Benson, I only have VW2018 but the preview image looks great. How did you do the calculation?

[Benson Shaw]

Hi, Nigel

 

Not sure of which calc you are referring to, but my file ported to v2018 attached here. I updated to add a 6th slope in the graphics. I'm surprised that the v2018  version is not reporting correctly.  If this problem is 4 versions old, many must have complained bitterly.  Or perhaps you and I are both missing a process to make it work.

 

My fictional DTM has a Pad in the proposed context, so seems to me that the worksheet report should report values correct values in all the columns in both exist and proposed sections.  Hoping someone will jump in, at least with a workaround.

 

-B

SlopeAnalysis v2018.vwx

[Benson Shaw]

ok testing some more.  I never really worked into this, so working in the dark.  Searched Help and found nothing helpful.

Here is what I found:

 

Projected Area fields for the various slopes are presumably the TopPlan projections of the sloped areas.

Surface Area fields would presumably be areas of the sloped surfaces.(Can anyone verify?)

 

Projected Area fields activate according to the OIP 2d Display options.

Update the worksheet after each change in OIP:

If 2d Display = Existing - the upper "Existing" worksheet area activates.

If 2d Display = Proposed - the lower "Proposed" worksheet area activates.

If 2d Display = Proposed and Existing - the upper "Existing" worksheet area activates, but NOT the lower Proposed area.

I did not succeed in simultaneously activating both Existing and Proposed sections of the report.

 

This obtains whether the drawing is displayed in TopPlan or any 3d view. Rendered or not.

 

Nothing I did activates the Surface Area column fields.

The OIP 3d Display setting is irrelevant

---3d Display choices do not activate the Surface Area Column

---Toggling 3d Exist/Proposed does not change the Exist/Proposed status of the worksheet Projected Area column.

 

And, it looks like the areas are reported in sq mm rather than drawing units, so some conversion required if other desired units.

Unfortunately, adding a conversion factor (eg/92903.04) in the column formula breaks the calc. It reports text of the forumla.

Forum search reveals complaints about aspects of Slope Analysis way back to v2010.

 

Does anyone have this working?

 

-B

 

 

 

 

[unearthed]

4 hours ago, Benson Shaw said:

Hi, Nigel

 

Not sure of which calc you are referring to, but my file ported to v2018 attached here. I updated to add a 6th slope in the graphics. I'm surprised that the v2018  version is not reporting correctly.  If this problem is 4 versions old, many must have complained bitterly.  Or perhaps you and I are both missing a process to make it work.

 

My fictional DTM has a Pad in the proposed context, so seems to me that the worksheet report should report values correct values in all the columns in both exist and proposed sections.  Hoping someone will jump in, at least with a workaround.

 

-B

SlopeAnalysis v2018.vwx 954.46 kB · 0 downloads

Sorry, by calculation I meant the table. I wonder if there have been complaints or simply giving up and walking away from parts of VW. I thought there'd be lots of chatter about it but almost nothing, and nothing useful.

 

I found almost nothing on the settings either (and Help is not), just this, which was hardly definitive and looks like VW put it the too-hard-basket:

 

 

[unearthed]

3 hours ago, Benson Shaw said:

ok testing some more.  I never really worked into this, so working in the dark.  Searched Help and found nothing helpful.

Here is what I found:

 

Projected Area fields for the various slopes are presumably the TopPlan projections of the sloped areas.

Surface Area fields would presumably be areas of the sloped surfaces.(Can anyone verify?)

 

Projected Area fields activate according to the OIP 2d Display options.

Update the worksheet after each change in OIP:

If 2d Display = Existing - the upper "Existing" worksheet area activates.

If 2d Display = Proposed - the lower "Proposed" worksheet area activates.

If 2d Display = Proposed and Existing - the upper "Existing" worksheet area activates, but NOT the lower Proposed area.

I did not succeed in simultaneously activating both Existing and Proposed sections of the report.

 

This obtains whether the drawing is displayed in TopPlan or any 3d view. Rendered or not.

 

Nothing I did activates the Surface Area column fields.

The OIP 3d Display setting is irrelevant

---3d Display choices do not activate the Surface Area Column

---Toggling 3d Exist/Proposed does not change the Exist/Proposed status of the worksheet Projected Area column.

 

And, it looks like the areas are reported in sq mm rather than drawing units, so some conversion required if other desired units.

Unfortunately, adding a conversion factor (eg/92903.04) in the column formula breaks the calc. It reports text of the forumla.

Forum search reveals complaints about aspects of Slope Analysis way back to v2010.

 

Does anyone have this working?

 

-B

 

 

 

 

Wow Benson you're drilled deeply. I haven't found a meaningful definition of Projected or Surface Area for the Slope Grid tool. 

 

Pat Stanford had a kludge working in 2016 (which I'll try later in week), but it's one-way as seems to break link with model:

I think Petri Saakinen had the last work in 2002:

"

"I am still awaiting for the 9.5.1 LandMark/Architect upgrade so need to ask:

Has the DTM slope analysis part been fixed?"

 

(Months later)
"I take that the deafening silence means 'no.' Ah well..."

 

I mean it is useful (and slopes conform to the data), just does not perform as advertised/ in the help.