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Geostatistical Analyst Layer-To-Contour results way too generalized

Question asked by dca.uw on Jan 1, 2018
Latest reply on Jan 3, 2018 by slynch-esristaff

Hi - I'm trying to produce contour polygons out of a Geostatistical Analyst layer. The contour polygons (GALayerToContour_ga tool) are super-generalized and look terrible. This screenshot shows is the resulting contour polygons in blue lines (transparent fill). The grid in the background was exported from the GA Layer (using the GALayerToGrid_ga tool), with the colors classified at the same cut-off elevations used to generate the contours:

 

My question is: How do I generate contour lines that really follow the data much more closely? Is there some kind of scale or generalization setting in the environments that I'm missing? Here is what I am running:

arcpy.GALayerToContour_ga(
    in_geostat_layer="output_geo_lyr",
    contour_type="FILLED_CONTOUR",
    out_feature_class=output_path,
    contour_quality="PRESENTATION",
    classification_type="MANUAL",
    classes_count="5",
    classes_breaks="5;20;75;150;999999")

Here is how I created the GA layer. It actually came from a raster-to-point export. For that reason, I set the min and max number of inputs to 1, to basically just make it a nearest neighbor interpolation:

arcpy.IDW_ga(
    in_features=in_features,
    z_field="grid_code",
    out_ga_layer="output_geo_lyr",
    out_raster="",
    cell_size="0.01",
    power="2",
    search_neighborhood="NBRTYPE=Standard S_MAJOR=1.1 S_MINOR=1.1 ANGLE=0 NBR_MAX=1 NBR_MIN=1 SECTOR_TYPE=ONE_SECTOR",
    weight_field="")

When I check the GA Layer with the GALayerToGrid_ga, it looks correct.That is the background in the screenshot above.

 

If I run the Spatial Analyst Contour List tool, that creates something much more reasonable. Of course, these are just lines, so they don't meet my needs, since I'm trying to create polygons. Here is a view of those:

 

Any ideas on how I can create polygons with boundaries that look like the lines in this screenshot? thanks!

 

The Python script I'm using is attached. It runs and produces the grid background and polygon foreground in the first screenshot, above. I'm using ArcGIS Desktop 10.5 with its arcpy 2.7.

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