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The first set of data you will be working with contains the Houston Police Department (HPD) beat boundaries. Though it has been modified for the purposes of this tutorial, the original data can be was obtained from the City of Houston GIS Database webpage, at http://cohgis.houstontx.gov/cohgis2010/index.html[g1] , within the administrative boundary dataset.which is no longer available, but the same data can be obtained from the GIS/Data Center data collection.

1. In the Catalog pane on the right, expand the Databases folder.
2. Expand the Geoprocessing geodatabase.
3. Right-click the HPDBeats_North feature class and select Add To New Map.
4. Right-click
5. On the right side of the screen, in the Catalog pane, under the Project tab, double-click Folders > GeoprocessingTutorialData.
6. Double-click the GeoprocessingData geodatabase to expand it.
7. Drag the HPDBeats_North feature class into the Map Display.
8. Drag the HPDBeats_South feature class into the Map Displayand select Add To Current Map.

Notice that the police beats in the City of Houston have been divided into two separate feature classes covering the northern and southern portions of the city respectively. You will now examine their attribute tables.

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Notice that the south layer contains 62 beats with the same data fields.

1. Close the attribute tables all table views.

At this point, you wish to combine the north and south police beats into a single layer. You will do so using a geoprocessing tool.

1. On the Analysis tab, click the Tools button.

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Notice that on the right side of the screen, where the Contents pane was, a Geoprocessing pane appears.

1. In the Geoproccessing pane, select Toolboxes, and then click Data Management Tools toolbox > General toolset > Merge tool.
2. In the upper right corner of the ‘Merge’ pane, click the help button.

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Read the Merge pane help and review the sample illustration.  Notice that this tool merges two like datasets covering different geographic extents together in a single dataset.

1. In the ‘Input Datasets’ drop-down menu, click the drop-down arrow and select the HPDBeats_South layer.

After selecting the HPDBeats_South layer, another drop-down window appears.

1. Click the second drop-down arrow and select the HPDBeats_North layer.

Notice that the when you hover over the Output dataset window, Output Dataset defaults to your default geodatabase (C:\Users\gistrain\Desktop\GeoprocessingTutorialData\HoustonSchoolsAndCrime\HoustonSchoolsAndCrime.gdb).

1. For ‘Output Dataset’, rename the feature class from “HPDBeats_South_Merge” or “HPDBeats_North_Merge” to “HPD_Beats.’
2. Leave all other settings as the default.
3.  Ensure that your merge pane appears like the pane below and click Run Run.

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Usually, it takes a few moments for the tool to begin executing. While the tool is running, you will notice text with the name of the running tool in the bottom right corner of the Map Display, as shown below.

When the tool is finished running, you will see a box pop-up in the bottom right portion of your monitor with the name of the tool. A green checkmark indicates that the tool ran successfully.

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1. In the Contents pane, right-click the HPDBeats layer and select Attribute  Attribute Table.

Scroll down the attribute table and notice that the attributes for both the north and south beats feature classes were preserved and combined into a single table with 117 beats.

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1. In the Contents pane, right-click the HPDBeats_North layer and select Remove.
2. In the Contents pane, right-click the HPDBeats_South layer and select Remove.
3. On the toolbar, click the Save button.

As explained in the tutorial introduction, the collaboration with the schools is going to be based on the police districts, not the police beats. At this point, your HPD layer only displays the police beat boundaries, but its attribute table does tell you the district number corresponding to each beat.

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1. For ‘Input Features’, drag in the HPDBeats layer from the Contents pane.
2. For ‘Output Feature Class’, rename the feature class from “HPD_Beats_Dissolve” to “HPDDistricts”.
3. For ‘Dissolve_Field(s)’, select the District field, since this is the field containing the common district values you wish to dissolve on.
4. Ensure that your Dissolve pane looks like the pane below, and click Run.

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1. In the Contents pane, toggle the new HPDDistricts layer off and on to understand the result of the Dissolve tool.
2. In the Contents pane, right-click the HPDDistricts layer and select Attribute Table.

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1. In the Contents pane, right-click the HPDBeats layer and select Remove.
2. Click the Save button.

Clip

Now you will examine the school district boundaries. Though it has been modified for the purposes of this tutorial, the original data can also be obtained online from the City of Houston GIS Database webpage at http://cohgis.houstontx.gov/cohgis2010/index.html[g2]  within the administrative boundary dataset.

1. On the right side of the screen, close the Geoprocessing pane.
2. In the Catalog pane, click Folders  Folders > GeoprocessingTutorialData > GeoprocessingData.gdb.
3. Drag the HISD feature class into the Map Display.

Notice that this feature class displays the boundary of the Houston Independent School District, which can be considered the study area boundary for this project. All of the other data layers you bring into your map document can be clipped to the study area boundary to reduce the size of the files you are working with, which will eliminate visual clutter and allow various processes to run more quickly. First, you will clip the police districts to the study area boundary.

1. In On the ribbon, click the Analysis tab.
2. , click the Tools button >Analysis Tools toolbox > Extract toolset > Clip tool.

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1. In the Contents pane, right-click the HPDDistricts layer and select Remove Remove.

You will now work with a dataset containing the locations of all violent crimes (including murder, rape, aggravated assault, and robbery) occurring in 2010, as reported by HPD. Though the data has been pre-processed for this tutorial, the original data tables can be obtained online from the Houston Police Department Crime Statistics webpage at http://www.houstontx.gov/police/cs/stats2.htm.

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1. Close the attribute table.
2. In the Contents pane, right-click the HPDCrime2010 layer and select Remove.
3. In the Contents pane, uncheck the HPDCrime2010_HISD and HISD layers, so that only the HPDDistricts_HISD layer is visible.
4. Click the Save button.

Buffer

The final dataset you will work with contains the locations of all the elementary schools in HISD. Though it has been modified for the purposes of this tutorial, the original data can be obtained online from the Texas Education Agency School District Locator Data Download webpage at http://schoolsdata2-tea-texas.opendata.arcgis.com/

1. On the right side of the screen, close the Geoprocessing pane.
2. In the Catalog pane, drag the HISDElemSchools feature class into the Map Display.
3. In the Contents pane, right-click the HISDElemSchools layer and select Attribute Table.

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1. Close the attribute table.
2. Click the Save button.
3. In the Contents pane, uncheck the HISDElemSchools layer and check the HPDCrime2010_HISD layer.

Spatial Join (Points to Polygons)

At this point, you can see all of the violent crime locations along with the half-mile school buffers, but much of the map is so densely covered with overlapping points that it becomes difficult to tell exactly how many points there are and to see the underlying school buffers. In addition, while you can see the spatial distribution of the points, you are not provided with any sort of useful summary of the data. Performing a spatial join will allow you to discover exactly how many violent crimes occurred within a half mile of each school in 2010.

The goal of performing a spatial join is to add a numeric field to the end of the school buffer attribute table that tells you how many crime points are contained within each school buffer.

1. In the Contents pane, right-click the HISDElemSchools_HalfMileBuffer layer and select Joins and Relates > Spatial Join
2. For ‘Join Features’, use the drop-down box to select the HPDCrime2010_HISD layer.
3. For ‘Merge Rule,’ click the drop down arrow to select Count.
4. For ‘Output Feature Class,’ rename the feature class from “Join_Output” to “HISDElemSchools_HalfMileBuffer_WithCrimeStats.”
5. Ensure that your Spatial Join pane appears like the pane below and click Run.

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The new layer should appear at the top of your Contents pane. 

1. Right-click the HISDElemSchools_HalfMileBuffer_WithCrimeStats layer and select Attribute  Attribute Table.
2. Notice the newly added Join_Count field.  This field tells you how many crime points are contained within each school buffer.
3. Close the attribute table.

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You can now easily tell which schools have the largest number of violent crimes occurring within a half mile radius.

1. Click the Save button.

Spatial Join (Polygons to Points)

You now have an attribute table that tells you the number of violent crimes that occurred within one year within a half mile of each school, but you would also like to have a table that tells you in which police district each elementary school lies. To create this table, you will perform another spatial join to add the attributes of the police beat to the back of each school that lies inside it.

1. In the Contents pane, uncheck the HISDElemSchools_HalfMileBuffer_WithCrimeStats layer and check the HISDElemSchools layer.

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1. Close the attribute table.

Searching for Tools

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In this tutorial, you navigated to various geoprocessing tools directly through the Toolbox; however, it is likely that when you go to work on your own, you may not remember exactly where all those tools are located.  As long as you can remember the name of the tool or what it does, you can find it using the search function.

1. On the Analysis tab, click the Tools button.
2. At the top of the Geoprocessing pane, in the Search box, type “Buffer” and press Enter.

Click on the first tool that says Buffer (Analysis Tools) to open th

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