Network dataset in GCS North America 1983

Question

I would like to build a street network dataset for routing purpose from data included on media kit ArcGIS 9.3. I try to use streets feature class, which is in GCS North America 1983. I hardly found any metadata and I assume that Speed field defines values in miles per hour, and Shape Length in degrees. I need two directions attributes??? distance and time. In a network wizard I used Shape (value created by a network) as distance evaluator field and Shape /Speed as time evaluator. I checked the results and distance looks all right, but time value does not make sense at all. I thought that this is problem with units and tried Shape/(Speed*26.8224) to change miles per hour to meters per minute, but still is does not return any reasonable result. I know I am missing something, but I can???t see what. Does anybody used successfully this dataset to build a network?

JoannaLaroussi · Answer

You were right about SP2: I installed it and finally was able to calculate Length. Thank you for all your help!

JaySandhu · Answer

Get the SP2 for 10 and then the python formula will work.
Or you can do the following:
Add your streets to ArcMap, then set the data frame property and choose an appropriate projection to display the data. Now open the attribute table, click on the newly added Miles field, right-click and choose "Calculate Geometry". Pick "Length" in the property and Miles for the units and make sure the Use Coordinate system of the data frame is checked on. Click Ok and it will fill in the projected length in miles for that field.
 
Jay Sandhu

JoannaLaroussi · Answer

I tried your Python formula: !Shape.Length@miles! And received an error: :invalid syntax(, line1), ERROR 00539:error running expression 0.105649822848036 I also tried: !Shape_Length@miles! error:Invalid field Shape_Lenght@miles !Shape!Lenght@miles error: ERROR 00539:error running expression: GPVARIANTOBJECT0Lenght@miles !Shape!Lenght@miles! error: ERROR 00539:error running expression: GPVARIANTOBJECT0Lenght@miles !Shape.Length!@miles error: ERROR 00539:error running expression: 1.52909253060023E03@miles I am using data from 9.3, but I have installed ArcGIS 10 on my desktop. Would be possible that this Python formula works only for ArcGIS 9.3?