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GIS-esque Problem
vonschoenborn
Member Posts: 1 
Contributor I
Hello,
I have a dataset that contains longitude and latitude coordinates along with some other attributes. I also have a second database that contains Zip Codes with their centroids (in longitude and latitude). For each example in the first dataset, I need to identify the Zip Code with the nearest centroid (second dataset). In other words, I need to use the good ol' distance formula [SQRT( (Lon2 - Lon1)^2 + (Lat2 - Lat1)^2 )] to calculate distances between each example in the first dataset to each example in the second dataset. I need to return the Zip Code associated with the minimum distance for each example in the first dataset (adding it as a new attribute). Below is what I have so far (not much). I've assigned a macro for each Longitude and each Latitude value in the Zip Code dataset. I was thinking that I could use a Loop Examples operator with an internal Generate Attribute operator to calculate distances for each example in the first dataset. Unfortunately, I can't find a way of making calculations based on every set of coordinates from the second dataset. Any help on this would be greatly appreciated.
Thanks,
Damian
I have a dataset that contains longitude and latitude coordinates along with some other attributes. I also have a second database that contains Zip Codes with their centroids (in longitude and latitude). For each example in the first dataset, I need to identify the Zip Code with the nearest centroid (second dataset). In other words, I need to use the good ol' distance formula [SQRT( (Lon2 - Lon1)^2 + (Lat2 - Lat1)^2 )] to calculate distances between each example in the first dataset to each example in the second dataset. I need to return the Zip Code associated with the minimum distance for each example in the first dataset (adding it as a new attribute). Below is what I have so far (not much). I've assigned a macro for each Longitude and each Latitude value in the Zip Code dataset. I was thinking that I could use a Loop Examples operator with an internal Generate Attribute operator to calculate distances for each example in the first dataset. Unfortunately, I can't find a way of making calculations based on every set of coordinates from the second dataset. Any help on this would be greatly appreciated.
Thanks,
Damian
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.1.003">
<context>
<input/>
<output/>
<macros/>
</context>
<operator activated="true" class="process" compatibility="5.1.003" expanded="true" name="Process">
<process expanded="true" height="569" width="925">
<operator activated="true" class="generate_data" compatibility="5.1.003" expanded="true" height="60" name="Data Set" width="90" x="45" y="30">
<parameter key="number_of_attributes" value="2"/>
<parameter key="attributes_lower_bound" value="-176.7"/>
<parameter key="attributes_upper_bound" value="70.7"/>
</operator>
<operator activated="true" class="rename" compatibility="5.1.003" expanded="true" height="76" name="Rename" width="90" x="179" y="30">
<parameter key="old_name" value="label"/>
<parameter key="new_name" value="DataValue"/>
<list key="rename_additional_attributes">
<parameter key="att1" value="Latitude"/>
<parameter key="att2" value="Longitude"/>
</list>
</operator>
<operator activated="true" class="set_role" compatibility="5.1.003" expanded="true" height="76" name="Set Role" width="90" x="179" y="75">
<parameter key="name" value="DataValue"/>
<list key="set_additional_roles"/>
</operator>
<operator activated="true" class="generate_data" compatibility="5.1.003" expanded="true" height="60" name="Zip Code DB" width="90" x="45" y="210">
<parameter key="number_examples" value="180"/>
<parameter key="number_of_attributes" value="2"/>
<parameter key="attributes_lower_bound" value="-176.7"/>
<parameter key="attributes_upper_bound" value="70.7"/>
</operator>
<operator activated="true" class="generate_attributes" compatibility="5.1.003" expanded="true" height="76" name="Generate Attributes" width="90" x="179" y="210">
<list key="function_descriptions">
<parameter key="ZIP" value="round(rand()*(70000-1)+1)"/>
</list>
</operator>
<operator activated="true" class="rename" compatibility="5.1.003" expanded="true" height="76" name="Rename (2)" width="90" x="179" y="255">
<parameter key="old_name" value="att1"/>
<parameter key="new_name" value="Latitude"/>
<list key="rename_additional_attributes">
<parameter key="att2" value="Longitude"/>
</list>
</operator>
<operator activated="true" class="select_attributes" compatibility="5.1.003" expanded="true" height="76" name="Select Attributes" width="90" x="179" y="300">
<parameter key="attribute_filter_type" value="single"/>
<parameter key="attribute" value="label"/>
<parameter key="invert_selection" value="true"/>
<parameter key="include_special_attributes" value="true"/>
</operator>
<operator activated="true" class="loop_examples" compatibility="5.1.003" expanded="true" height="76" name="Loop Examples" width="90" x="313" y="300">
<process expanded="true" height="551" width="870">
<operator activated="true" class="extract_macro" compatibility="5.1.003" expanded="true" height="60" name="Extract Macro" width="90" x="45" y="30">
<parameter key="macro" value="Lat%{example}"/>
<parameter key="macro_type" value="data_value"/>
<parameter key="attribute_name" value="Latitude"/>
<parameter key="example_index" value="%{example}"/>
</operator>
<operator activated="true" class="extract_macro" compatibility="5.1.003" expanded="true" height="60" name="Extract Macro (2)" width="90" x="179" y="30">
<parameter key="macro" value="Lon%{example}"/>
<parameter key="macro_type" value="data_value"/>
<parameter key="attribute_name" value="Longitude"/>
<parameter key="example_index" value="%{example}"/>
</operator>
<connect from_port="example set" to_op="Extract Macro" to_port="example set"/>
<connect from_op="Extract Macro" from_port="example set" to_op="Extract Macro (2)" to_port="example set"/>
<connect from_op="Extract Macro (2)" from_port="example set" to_port="example set"/>
<portSpacing port="source_example set" spacing="0"/>
<portSpacing port="sink_example set" spacing="0"/>
<portSpacing port="sink_output 1" spacing="0"/>
</process>
</operator>
<connect from_op="Data Set" from_port="output" to_op="Rename" to_port="example set input"/>
<connect from_op="Rename" from_port="example set output" to_op="Set Role" to_port="example set input"/>
<connect from_op="Zip Code DB" from_port="output" to_op="Generate Attributes" to_port="example set input"/>
<connect from_op="Generate Attributes" from_port="example set output" to_op="Rename (2)" to_port="example set input"/>
<connect from_op="Rename (2)" from_port="example set output" to_op="Select Attributes" to_port="example set input"/>
<connect from_op="Select Attributes" from_port="example set output" to_op="Loop Examples" to_port="example set"/>
<portSpacing port="source_input 1" spacing="0"/>
<portSpacing port="sink_result 1" spacing="0"/>
</process>
</operator>
</process>
0
Answers
A brief think leads me to come to the conclusion that is a relatively tricky thing to do. Those fine Rapid-I chaps might want money for this sort of advice but data mining is my hobby and I'm on holiday at the moment so onwards...
I would start with the Cross Distances operator to determine the pairwise distances between the data examples and the reference examples. Next I would use the Aggregation operator to find the minimum distance for each data example.
Then I would need to think a bit harder - I'm guessing that Join might be the next step with "inner" as the option.
From there I'm guessing (wildly now as I'm sure you will understand) that the use of the Replace(Dictionary) operator is the final step.
Use of the word "Gymnastics" is entirely appropariate in the context of creating processes but it is a whole lot better than writing code and it keeps you supple.
Anyway - I'm off to the Taverna for a well earned.
Andrew