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Selecting within a selection

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4
2 weeks ago
MonicaClayton
by
Emerging Contributor
2 weeks ago

I have a file with land use and building footprints. I have gotten to the point in python of selecting all the land use shps from the object attributes. In this picture:

MonicaClayton_0-1726665109527.png

I have written code that has selected everything tagged as residential in the object attributes.

 

def selectByAttribute(attr, value):
    shapes = getObjectsFrom(ce.scene)
    selection = []
    for s in shapes:
        attrvalue = ce.getAttribute(s, attr)
        if attrvalue  ==  value:
            selection.append(s)
        
    ce.setSelection(selection)

if __name__ == '__main__':
    selectByAttribute("landuse","residential")
    pass

 

 

My question then becomes, how do I select the footprints within those already selected polygons, and nothing else? This is where I have gotten stuck.

Please help? And help me like I have no coding knowledge what so ever. I have an art degree, and the above took me almost 2 days to figure out.

Thanks in advance!!!!

Monica

 

Edit: Essentially, I would like to "Select by Location" like I would in ArcPRO. Which, would be a nice feature to have in general.

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4 Replies
desert
by
Occasional Contributor
2 weeks ago

I have referred to the link below.

getObjectsFrom

 

desert_1-1726716844128.png

 

change

shapes = getObjectsFrom(ce.scene)

to

shapes = getObjectsFrom(ce.selection, ce.isShape)

 

I hope this helps.

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MonicaClayton
by
Emerging Contributor
2 weeks ago

I did, and it gave me the same results. I want to select the footprints that are within the already selected land use polygons. Like my edit, a "Select by Location" option and the location being within my already selected polygons. Is this possible? There isn't any specific or differentiating attribute on the footprints that I can use to pick them out, the only thing they all have in common is the fact they are within a polygon tagged as "landuse, residential". 

 

Thank you for the help!!

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JonasObertuefer
by Esri Contributor
Esri Contributor
2 weeks ago

Hi @MonicaClayton,

There is way to do this in CityEngine although it is a rather complex workflow:

Asumming you have the landuse and footprint shapes in a different shape layer

  1. Select all landuse shapes
  2. Apply & Generate the following CGA on them:
    attr landuse = "residential"

Lot --> 
	t(0,-5,0)  
	extrude(10)
	label(landuse)
	color(1,0,0.5)​
  3. Connect the object attribute to the landuse attribute in the Inspector, if they are not automatically connected
  4. Select all footprints and assign&generate the following CGA onto them:
    Lot -->
	contextCheck

contextCheck -->
	case inside(inter, "residential") : 
		color(1,0,1) 
		report("landuse", "residential") 
		extrude(15)
	// add more cases for all usages
	else: extrude(15)​
  5. Add a new python file to the Scripts folder of the project
    from scripting import *

# Get a CityEngine instance
ce = CE()
    
# Called for each shape after generation.
def finishModel(exportContextOID, shapeOID, modelOID):
    ctx = ScriptExportModelSettings(exportContextOID)
    shape = Shape(shapeOID)
    model = Model(modelOID)
    
    reports = model.getReports()
    if 'landuse' in reports:
        ce.setAttribute(shape, "landuse", reports['landuse'][0])​
  6. With the footprints still selected go to File -> Export -> Script Based Export (Python). Select the previously created python script and click on Finish
  7. All footprints inside a landuse shape will have a new landuse object attribute with the value of their respective surrounding landuse shape.
  8. Select them using your python script from above

I hope this is what you want to achieve. Let me know if you have any questions!

Cheers
Jonas

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