[GIS] Modify raster layer display and symbology properties programmatically with arcpy or ArcObjects

arcgis-10.0arcobjectsarcpyrastersymbology

I have over 1500 NITF files that I need to be able to modify the layer display and symbology of programmatically from within ArcMap. I need to set the properties outlined in red below:

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I've looked through the arcpy docs and it doesn't look like these properties are exposed – honestly, I didn't expect them to be. I have a feeling I can get to them through ArcObjects. Anyone had any experience/luck modifying these properties programmatically?

Best Answer

I believe stretched raster symbology is rendered via RasterStretchColorRampRenderer, so interfaces implemented by this class are a good start. The renderer is assigned to your raster layer through IRasterLayer.Renderer.

Stretch type: IRasterStretch.StretchType
High/low stretch values: IRasterStretchMinMax

Orthorectification is controlled by a different set of interfaces, pertaining to the raster data source itself. IRaster2.GeodataXform can point to a geodata transformation class implementing ISensorXform which contains the orthorectification properties you see in the layer's property page.

Related Solutions

[GIS] Using ArcPy to get layer symbology

For ArcGIS 10.0, if you can make use of a read-only approach, the following code sample reveals the field (and joined table) that forms the basis for the symbology of a layer. It exports a temporary msd(a zip containing xml files) and loads the specific attributes into an object. These classes might be extended to gain access to additional layer attributes.

import zipfile
from arcpy import mapping
import os
from xml.dom.minidom import parse


class LayerExtras(object):
    """ An object to hold attributes loaded from xml inside the msd."""

    name = ""
    symbologyFieldName = ""


class MxdExtras(dict):
    """ Exposes extra MXD details by raiding an exported msd

        Treat this object as a dictionary with layer name as the key and a custom object
        with desired attributes as the value.
        You must have write access to MXD directory (creates temporary msd file).
        Only layers in the first dataframe are accessed.

    """    

    LYR_NAME_NODE = "Name"
    LYR_SYMBOL_NODE = "Symbolizer"
    LYR_FIELD_NODE = "Field"
    MSD_SUFFIX = "_MxdExtrasTemp.msd"
    MXD_SUFFIX = ".mxd"
    EXCLUDED_FILE_NAMES = ["DocumentInfo.xml", "layers/layers.xml"]
    mxdPath = ""

    def __init__(self, mxdPath):

        self.loadMxdPath(mxdPath)


    def loadMxdPath(self, mxdPath):
        """ Load mxd from file path """

        self.mxdPath = mxdPath.lower()
        mxd = mapping.MapDocument(self.mxdPath)

        msdPath = self.mxdPath.replace(self.MXD_SUFFIX, self.MSD_SUFFIX) 

        # Delete temporary msd if it exists
        if os.path.exists(msdPath):
            os.remove(msdPath)

        mapping.ConvertToMSD(mxd,msdPath)

        zz = zipfile.ZipFile(msdPath)

        for fileName in (fileName for fileName in zz.namelist() if not fileName in self.EXCLUDED_FILE_NAMES):
            dom = parse(zz.open(fileName))
            name, lyr = self.loadMsdLayerDom(dom)
            self[name] = lyr
        del zz
        os.remove(msdPath)

    def loadMsdLayerDom(self, dom):
        """ Load dom created from xml file inside the msd. """

        lyr = LayerExtras()  

        # Layer name
        lyr.name = dom.getElementsByTagName(self.LYR_NAME_NODE)[0].childNodes[0].nodeValue

        # Symbology field name
        symbologyElement = dom.getElementsByTagName(self.LYR_SYMBOL_NODE)[0]
        lyr.symbologyFieldName = symbologyElement.getElementsByTagName(self.LYR_FIELD_NODE)[0].childNodes[0].nodeValue

        return lyr.name, lyr


############
# Test

if __name__ == "__main__":

    mxdPath = r"c:\temp\AmphibianSpeciesRichnessAverageOf30mCells.mxd"

    mxde = MxdExtras(mxdPath)

    for lyr in mxde.itervalues():
        print "Layer Name: ", lyr.name 
        print "Layer Symbology Field Name: ", lyr.symbologyFieldName
        print

Example output of test:

Layer Name:  Amphibian Species Richness Average of 30m Cells
Layer Symbology Field Name:  biodiversity.AmphAve

[GIS] Dealing with overlapping grid (and graticule) labels using ArcGIS Desktop

This is not much of an answer but it would not fit in the comment window;

You can do this with ArcObjects. I made a tool into which I enter parameters (extent, x and Y spacing) and it will create the grid in a existing polyline feature class. It's not too coplex to do this with ArcObjects but do create something like this does require a solid understanding of ArcObjects and VS.Net programming concepts. To do this dynamically for changing scales and to control labeling with ArcObjects would be a fairly complex add-in. (controlling dynamic labels programatically is difficult, at least I found it so) I only do a little bit of python mostly for geoprocessing for which it is primarily intended but I am pretty sure this cannot be done with python. Take this last statement with a grain of salt because I have not yet downloaded version 10.1 and I believe Python functionality has been extended in the new version. With ArcObjects however you can, among other things, control every aspect of the ArcMap framework which also allows you capture the extent of the layout extent and transform it real world coordinates and vice versa.

My add-in is a lot simpler then what you are looking for but it would be a good start. As I mentioned it creates the grid in a feature class based on the parameters you enter. It optionally stores coordinates as attributes and I then use maplex for labeling. Maplex has enough options to let me control where the grid labels should appear but then again I only do this in documents with a set extent.

If you'd like I can post the Add-in. If you want to improve it I will also post the source code.

Best Answer

Related Solutions

[GIS] Using ArcPy to get layer symbology

[GIS] Dealing with overlapping grid (and graticule) labels using ArcGIS Desktop

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