It looks like after installing ArcGIS 10.1 SP1, if you have background processing enabled for geoprocessing, you cannot use a VB expression type for the calculate fields tool. Even though VB is still the default expression type.

So if you have a script that calls arcpy.AddField_management() without defining Python as the expression type its not going to run if background processing is enabled...

ArcGIS Toolbox: Loading script tool parameter defaults from a config file.

Lets say we create a script tool to run in ArcGIS Desktop and it has 10 parameters. On average the user only needs to change one of those parameters to run the tool 98% of the time.

We make each parameter available because hard coded  parameters can kill your tool 2% of the time. Or maybe more like 10%.... Whatever.

Its best to have all the parameters exposed in the tool dialog and loaded with the defaults your going to use 98% of the time. If these defaults are the same across many tools you don't want to be going into each tool's parameters to set the defaults. You want one location to set all the defaults. That's your config file bro.

So here is an example of one tool's tool validator that loads the defaults from a config file located in the same directory as the toolbox we are running the tool from.


import sys
import os
import ConfigParser
import arcpy

# Finds the path of the toolbox
scriptPath = sys.path[0]
# The config file should be in the same directory as the toolbox
configFile = scriptPath + "\\amp_config.cfg"

class ToolValidator:
  """Class for validating a tool's parameter values and controlling
  the behavior of the tool's dialog."""

  def __init__(self):
    """Setup arcpy and the list of tool parameters."""
    self.params = arcpy.GetParameterInfo()
    #Group the following parameters in the dialog box
    self.params[2].category = "Defaults"
    self.params[3].category = "Defaults"
    self.params[4].category = "Defaults"
    self.params[5].category = "Defaults"
    self.params[6].category = "Defaults"
    self.params[7].category = "Defaults"

  def initializeParameters(self):
    """Refine the properties of a tool's parameters.  This method is
    called when the tool is opened."""
    return

  def updateParameters(self):
    """Modify the values and properties of parameters before internal
    validation is performed.  This method is called whenever a parmater
    has been changed."""
    # If the config file is not found the parameters remain blank.
    if not os.path.exists(configFile):
     self.params[2].value = ""
     self.params[3].value = ""
     self.params[4].value = ""
     self.params[5].value = ""
     self.params[6].value = ""
     self.params[7].value = ""
     return
   
    #If the config file is found it moves on to populate the parameters.
    # Adds defalut values from the config file when the first paramter is filled for the first time.
    if self.params[0].altered and not self.params[0].hasBeenValidated:
      if not self.params[0].value == None:
        # Loads the config file into memory
        config = ConfigParser.SafeConfigParser()
        config.readfp(open(configFile))
       # Gets the values from the config file.
        scratchDir = config.get('environment','scratchDir')
        coverageName = os.path.basename(str(self.params[0].value))
        logFile = scratchDir + "\\" + coverageName + "_log.txt"    
        self.params[3].value = logFile
        self.params[4].value = coverageName
        self.params[6].value = scratchDir + "\\" + coverageName + "_cov.gdb"
        self.params[2].value = scratchDir
        self.params[5].value = config.get('dataConversion','coverageList')
        self.params[7].value = config.get('dataConversion','annotationLayerList')
# If parameter 1 is false then parameter 7 is greyed out.
    if self.params[1].value == False:
      self.params[7].enabled = False
    else:
      self.params[7].enabled = True
    return

  def updateMessages(self):
    """Modify the messages created by internal validation for each tool
    parameter.  This method is called after internal validation."""
    return

ArcGIS Project Management with Production Mapping

ESRI's Production Mapping has a lot of useful tools and functionality. I think its kind of like that drawer in your house where you put things that are really great for something but not necessarily needed for anything.

For me the documentation is rarely clear or concise enough to understand so I just have to tinker with it until I find something that works.

Recently I dove into the Product Library. I am working on a project where the product will be a workflow to create maps. The workflow includes some script tools but the goal is to use as much out of the box functionality as possible. Anyways, the development process requires setting up MXDs, tool boxes, scripts with config files, layout rules, styles, and just about anything else GIS related. It turns out the Product Library is a great way to sync all these things between team members.

I have not really figured the structure yet but after setting up a "Solution"  and a "Product Class" we are able to check in and out everything to a versioned SDE database. If we choose to check everything out to the same location on our respective machines the MXDs, toolboxes and what not stay working.

I'm just saying its neat that's all.

Converting Decimal Degrees to Degrees Minutes Seconds with Python

Thanks to this post at Another GIS Blog I was saved the time of having to figure out how to do this calculation on my own.

And I just the author posted that TODAY, just 8 hours ago. That is crazy.

Thanks Guy.

Scratch Names

I was always wishing there was an easy way to create a unique scratch name for outputs of geoprocessing scripts. Today I found the simple solution http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/CreateScratchName/000v0000001z000000/

The Create Scratch Name code does just that so if you are making a temporary copy of  features or a temporary buffer or whatever you can slap this line in and have it make names for you. Its great for someone like me that has to run their code 70 times before finishing it.

Unique IDentification

I don't know how I missed this, but the Global ID (GUID) field in ArcGIS gives you a hands free way to add unique ids to features. The Add Global IDs tool will create the field and populate it with the ID. The GlobalID will stick with the features as you edit or join or export or clip or whatever. This will allow you to trace back and maintain relationships.

I will start using this in everything. No more staring at the attribute table to see what I can combine to make a Unique ID.