Hi Folks,

For the past week I have been using MapForce. It is a fun and neat tool for mapping data. However, I have encountered some challenges with it, which I describe below. Perhaps those people on the list who are experienced with MapForce can identify where I am not understanding correctly?  /Roger

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I have location data to 6 digits precision (i.e., 6 digits past the decimal point). I want to fuzz the location data to 2 digits precision. Plus I want to preserve size. Thus, the last 4 digits will be set to zeroes. For example, I want to map this location data:

<location>

    <altitude>30000</altitude>

    <latitude>42.364978</latitude>

    <longitude>-71.022362</longitude>

</location>

to this:

<location>

    <altitude>30000</altitude>

    <latitude>42.360000</latitude>

    <longitude>-71.020000</longitude>

</location>

Notice that the latitude and longitude values have been fuzzed and size is preserved.

Here’s how I did the mapping: MapForce has a “round-precision” component that rounds a decimal number to the number of digits you specify (I specified 2). And it has a “format-number” component which formats a number according to a pattern (I specified 000.000000 as the pattern). Here is the mapping that I created using MapForce:

Goodness’s

The mapping is done graphically by simply dragging components from a palette onto a canvas and then wiring the components together. No coding. No programming.

This is good.

Once you’re done creating the mapping you can auto-generate code. The code can take any input, perform the mapping on it, and generate the output. MapForce does any-to-any mapping and conversion of:

• XML
• JSON
• Database data
• Text and flat files
• Excel
• EDI
• XBRL
• Google Protocol Buffers
• SOAP web services
• REST web services

“What is the programming language of the auto-generated code?”, you ask. Answer: you get to choose the programming language that you want MapForce to generate. MapForce can auto-generate code for any of these languages:

• XSLT (v1, v2, and v3)
• XQuery
• Java
• C#
• C++

This is good.

Challenges

I ran MapForce’s tool to auto-generate code and specified XSLT 2.0 as the desired programming language. When I did so, I got this message:

Recall that I used the “round-precision” component. Well, XSLT doesn’t have a round-precision function (it does have a round function). So, MapForce refused to generate XSLT code for my mapping.

On the other hand, Java, C#, and C++ do have a round-precision function so MapForce happily generated Java, C#, and C++ code.

But I really wanted XSLT code, so I reworked my mapping to use components that I knew are available in XSLT. In my new mapping I did the fuzzing by first applying the format function with pattern 0.00 and then concatenating 0000 onto the result:

Now MapForce happily generated XSLT code. Oddly, format-number is not part of XQuery, so MapForce refused to generate XQuery code. However, it did generate Java, C#, and C++ code.

Lesson Learned: not all the components on the MapForce palette are usable by all the programming languages. So a user of MapForce has to know which components to avoid.

That is a challenge.

Okay, now I’ve auto-generated XSLT code for my mapping (the second mapping, the one that uses concat). Exciting! Let me run it against an input.

I ran the XSLT that MapForce generated on this input:

<location>

    <altitude>30000</altitude>

    <latitude>42.364978</latitude>

    <longitude>-71.022362</longitude>

</location>

It produced this output:

<location>

    <altitude>30000</altitude>

    <latitude>42.36</latitude>

    <longitude>-71.02</longitude>

</location>

Yikes! What happed to the last 4 digits of latitude and longitude?

I examined the XSLT and found out what happened. Before I tell you, however, I need to show you my XML Schema for location:

<xs:element name="location">
    <xs:complexType>
        <xs:sequence>
            <xs:element name="altitude" type="xs:integer" />
            <xs:element name="latitude" type="xs:decimal" />
            <xs:element name="longitude" type="xs:decimal" />
        </xs:sequence>
    </xs:complexType>
</xs:element>

Notice that the type for latitude and longitude is xs:decimal. That is important.

As I said, I examined the XSLT. I found that it formats the number first. For example, it formats this latitude:

42.364978

to this:

42.36

Then it concatenates 4 zeroes, which generates this value:

42.360000

And then, since the XML Schema says the value is of type xs:decimal, it casts the value to xs:decimal, which yields this:

42.36

Casting to xs:decimal results in discarding the non-significant trailing 4 digits!

How to fix this? Well, one solution is to modify the XML Schema and specify xs:string as the datatype for latitude and longitude:

<xs:element name="location">
    <xs:complexType>
        <xs:sequence>
            <xs:element name="altitude" type="xs:integer" />
            <xs:element name="latitude" type="xs:string" />
            <xs:element name="longitude" type="xs:string" />
        </xs:sequence>
    </xs:complexType>
</xs:element>

Perhaps there is another solution which doesn’t involve altering my XML Schema?

/Roger