Given the below parameters (from Nearest Neighbor Analysis): A) Is there a definite range my Radius value should be within? B) Are there definite values my cell size should be near? C) Is there a definite range my color map values should encompass or exclude?

What might the values be?

Observed mean distance:0.00550684136246
Expected mean distance:0.00927189095586
Nearest neighbor index:0.593928615929

Layer metadata:

X: 656 Y: 501 Bands: 1 
Origin: -75.2615,40.133
Pixel Size: 0.000475715,-0.000475715
No Data Value: -9999 
Data Type: GDT_Float32 - Thirty two bit floating point 
Pyramid overviews:
Layer Spatial Reference System: 
+proj=lcc +lat_1=40.96666666666667 +lat_2=39.93333333333333 +lat_0=39.33333333333334 +lon_0=-77.75 +x_0=600000 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=us-ft +no_defs
Layer Extent (layer original source projection): 
-75.2614514397764793,39.8947150902235208 : -74.9493824749561242,40.1330482478073591

Thank you for all the help.

  • 2
    It appears your coordinates are latitude and longitude. This introduces about a 40% distortion of north-south distances compared to east-west distances; with enough data, that artifact alone can produce "significant" results (as indicated by the large absolute value of the z-score). Before you worry about any other settings, then, you should apply a suitable (low-distortion) projection to the data and start over using the projected coordinates. – whuber Feb 20 '13 at 17:25
  • 1
    I appreciate the advice on coordinates; I'm still wrapping my mind around project CRS, layer CRS, and projection. If I have the project coordinates set to: EPSG:2272 NAD83 / Pennsylvania South (ftUS), and 'On the Fly transformations" turned on, am I still getting distortions due to the layer CRS? – Fred Feb 20 '13 at 19:33
  • 1
    Also, I'm still interested in knowing (as long as my layers are aligned and they are) how to produce descriptive heat map. In this case I'm wondering how nearest neighbor measurements might guide my experiments (or not). – Fred Feb 20 '13 at 19:40

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