8 replies to this topic

[cmdrico7812]

"I
want to utilize the HotSpot Analysis tool in ArcMap to look for spatial
correlations of several features of parcels in my township. However,
whenever I run the tool, I get the following error:

Cannot overwrite: D:WorkspaceTWP_FILESGIS_FILESSHAPEFILESSTATSHousing_Cond
Error in script HotSpots.
Error
in executing: cmd.exe /C C:PROGRA~1ArcGISARCTOO~1ScriptsGi.py
""Raster_ConvertHousing Condition"" ""Res_Condition5.AVERAGE""
""D:WorkspaceTWP_FILESGIS_FILESSHAPEFILESSTATSHousing_Cond""
""Inverse Distance"" ""Euclidean Distance"" ""None"" ""0"" ""#"" ""#"" ""GiUnknown""

Failed to execute (HotSpots_5).

Does anyone have experience with this tool and its use? Thanks for your help!

Eric "

[ajbaum77]

"Sounds
like it is trying to overwrite or add data to a shapefile that is read
only, try saving a copy of the shapefile Housing_Cond somewhere else on
your hard drive and using that for the analysis.
-Andrew

I 
want to utilize the HotSpot Analysis tool in ArcMap to look for spatial 
correlations of several features of parcels in my township.
However, whenever I run the tool, I get the following error:

Cannot overwrite: D:WorkspaceTWP_FILESGIS_FILESSHAPEFILESSTATSHousing_Cond
Error in script HotSpots.
Error 
in executing: cmd.exe /C 
C:PROGRA~1ArcGISARCTOO~1ScriptsGi.py  ""Raster_ConvertHousing 
Condition"" ""Res_Condition5.AVERAGE"" 
""D:WorkspaceTWP_FILESGIS_FILESSHAPEFILESSTATSHousing_Cond"" 
""Inverse Distance"" ""Euclidean Distance"" ""None"" ""0"" ""#"" ""#"" ""GiUnknown""

Failed to execute (HotSpots_5).

Does anyone have experience with this tool and its use?  Thanks for your help!

Eric

http://

"

[cmdrico7812]

Would
<Null> values have anything to do with it? I assumed that the
script would ignore <null> values or make them zero but I could
be wrong. Thanks.

[ajbaum77]

Null
values in a numeric field could indeed have something to do with it but
those should have been turned into zeros automatically anyway. Is the
script trying to write data into existing fields in the shapefile? If
it is they fields may not be of the correct type. Even if the fields
need to be numeric and are they may need to be created as a double
field or float field instead of a short or long integer.

[cmdrico7812]

"I
got the analysis to work. I now have a GiInvDst value for each parcel
based on the calculation. I have never really worked with this type of
analysis before so I'm not entirely sure how to interpret the results.
For instance, I did a hot spot analysis for the total number of police
calls to each parcel over the last 6 years. I was hoping to find a
clustering of high and low values. The GiInvDst range for the parcels
is from 3.14 to -1.31. I know that if the Gi is high it means that
there is a clustering of parcels with a value higher than the mean for
all parcels and a low Gi means that there is a clustering of parcels
with a value lower than the mean for all parcels. What I don't know is
how high or low the Gi should be. I've attached a screen shot showing
the gradiated Gi values for each parcel. Based on this information
could anyone give me a rough interpretation of the data. Just enough so
that I see where I could head with this and continue with future
analyses of other variables. Thanks in advance!

Eric

Attached thumbnail(s)
[url="http://"http://www.cartotalk.com/index.php?act=Attach&type=post&id=372"]http://"http://www.cartotalk.com/index.php...ype=post&id=372[/url] "

Attached Files

•  hotspot.jpg   530.44K   76 downloads

[ajbaum77]

First I'm glad you got the analysis to work, what turned out to be the problem?

While I have never used this tool, let me see if I can help you
interpret the results. Now remember I'm just going by the information
you have posted and could be way off. It seems to me by coding the
police calls to each parcel you are defeating the purpose of the hot
spot analysis. If you were to run the analysis on a point file with a
single point for each police call, centered on the corrsponding parcel,
(it would be OK to have multiple points on top of each other) then you
would end up with an output that would show the area with the highest
concentration of calls and then shade the rest of the results based on
their relative distance from the areas of highest concentration. But
like I said I have not used this tool and am not familiar with the
inputs or the script so this may be completely wrong.

[cmdrico7812]

I
understand your explanation of doing the point locations of each police
call then seeing the proximity of parcels to the dots. How can I create
a point shapefile from a polygon file based on a field? In other words,
how can I create a point file that places a point inside each polygon
for each call to that parcel? Currently, the only relationship to a
spatial location I have for each call is based on the location of the
polygon parcel layer. Thanks in advance.

Eric

[burwelbo]

You
can use the Feature to Point tool to create a centroid location from
each polygon. That transfers the attributes to the point file as well.
If you have multiple points per polygon you need to do a spatial join.

Good luck
Bruce

[mike]

"

I 
understand your explanation of doing the point locations of each police 
call then seeing the proximity of parcels to the dots.  How can I 
create a point shapefile from a polygon file based on a field?  In 
other words, how can I create a point file that places a point inside 
each polygon for each call to that parcel?  Currently, the only 
relationship to a spatial location I have for each call is based on the 
location of the polygon parcel layer.  Thanks in advance.

Eric

http://

You can convert features to points and still retain the attribute information through the Feature to Point tool in ArcToolbox. "