Creating Weights Matrix

[morg...@appstate.edu]

Hello,

I am trying to create a weights matrix in GeoDa. The data are housing sales and each property has an ID. However, some properties have multiple sales so appear more than once. When I try to create a weights matrix I'm told that there are duplicate values. How can I get around this? Thank you.

[Frank Howell]

Hi,

This is more of a data conceptualization issue than a spatial weights issue. Effectively, you have a time-embedded element in that multiple sales occur over time, right? What theoretical issue are you trying to understand better with the housing sales data? If the sales range over time, the multi-sales properties could be restricted to the "latest" sale which is the same temporal slice as the other, "single-sales," data elements. Just select the "latest sale" record for the same ID. That is one approach. If I do not understand your issue, please elaborate.

Frank Howell

Editor-in-Chief

Spatial Demography

Springer Media

On Sat, Jun 2, 2018 at 10:40 AM, <morg...@appstate.edu> wrote:

Hello,

I am trying to create a weights matrix in GeoDa. The data are housing sales and each property has an ID. However, some properties have multiple sales so appear more than once. When I try to create a weights matrix I'm told that there are duplicate values. How can I get around this? Thank you.

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[Ash Morgan]

Thanks for the response. That should work. Can that be done directly in GeoDa or I could do it in Exel before joining it with the shapefile?

Thanks again for your input. 

On Sat, Jun 2, 2018 at 2:28 PM Frank Howell <frankm...@gmail.com> wrote:

Hi,

This is more of a data conceptualization issue than a spatial weights issue. Effectively, you have a time-embedded element in that multiple sales occur over time, right? What theoretical issue are you trying to understand better with the housing sales data? If the sales range over time, the multi-sales properties could be restricted to the "latest" sale which is the same temporal slice as the other, "single-sales," data elements. Just select the "latest sale" record for the same ID. That is one approach. If I do not understand your issue, please elaborate.

Frank Howell

Editor-in-Chief

Spatial Demography

Springer Media

On Sat, Jun 2, 2018 at 10:40 AM, <morg...@appstate.edu> wrote:

Hello,

I am trying to create a weights matrix in GeoDa. The data are housing sales and each property has an ID. However, some properties have multiple sales so appear more than once. When I try to create a weights matrix I'm told that there are duplicate values. How can I get around this? Thank you.

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Ash Morgan

Professor, Department of Economics

Director, Center for Economic Research and Policy Analysis
Appalachian State University
3094 Peacock Hall
416 Howard Street
Boone, NC 28608
Office: 828-262-2927
Website: http://www.appstate.edu/~morganoa/

[Frank Howell]

I’m writing from my iPad without geoda available. If you have the sale date as a field, sort by ID and sale date so you can determine the duplicate IDs by sale date. Just delete the duplicate ID records except for the latest sale date. Save the file under a new name.

You can do this in Excel but you may be able to do similar sorting in Geoda as well. 

Hope this helps!

Frank

On Sat, Jun 2, 2018 at 12:01 PM Frank Howell <frankm...@gmail.com> wrote:

Hi,

This is more of a data conceptualization issue than a spatial weights issue. Effectively, you have a time-embedded element in that multiple sales occur over time, right? What theoretical issue are you trying to understand better with the housing sales data? If the sales range over time, the multi-sales properties could be restricted to the "latest" sale which is the same temporal slice as the other, "single-sales," data elements. Just select the "latest sale" record for the same ID. That is one approach. If I do not understand your issue, please elaborate.

Frank Howell

Editor-in-Chief

Spatial Demography

Springer Media

On Sat, Jun 2, 2018 at 10:40 AM, <morg...@appstate.edu> wrote:

Hello,

I am trying to create a weights matrix in GeoDa. The data are housing sales and each property has an ID. However, some properties have multiple sales so appear more than once. When I try to create a weights matrix I'm told that there are duplicate values. How can I get around this? Thank you.

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To unsubscribe from this group and stop receiving emails from it, send an email to openspace-lis...@googlegroups.com.
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[Frank M. Howell]

Ash,

You’ll have to rejoin the shapefile with the new attribute data...unless Geoda will allow you to sort/edit the table in this manner. Sorry, I’m on an iPad and can’t verify.

Frank