#QGIS DEFINE RASTER EXTENT INSTALL#

Click OK, and the new shapefile will be added to the map.The user may use the Topography Layer in a wide variety of ways, including:.

For this example, the input vector layer is the nationwide census tracts, the clip layer is the NC state boundary.

Output shapefile: the folder where you want to save the new shapefile to and the name of the new shapefile.

This will typically be a state, country, etc.

Clip layer: the boundary you want to clip the input layer to.

Input vector layer: the larger shapefile.

There are 3 areas to this tool you will need to be concerned with:.

Click the Vector menu at the top of the QGIS program, mouse-over Geoprocessing Tools, and click Clip.

(With the Spatial Query tool you have not changed the dataset or created a new shapefile, it is only a visual change.) This tool creates a new shapefile whereas the Spatial Query only displays the new information. For this example, I have nationwide census tracts and a North Carolina state boundary, and I want a layer of just the census tracts in North Carolina. At least in some versions of QGIS, they will need to be in the same projection.

To use the Clip tool, you will need 2 shapefiles.

Under 'Encoding you will need to check 'Save only selected features.' Click OK.

You will need to specify an output location under the Save as area.

Right click the larger layer that has the selected features (i.e.

U sing the same data from above, it will be North Carolina.

Set the 'Reference features of' option to the layer you want the input features to be clipped to (i.e., the 'cookie cutter' layer).

Set the 'Where the feature' option to 'Within.' **NOTE: this option changes amongst the different QGIS versions and you should use the one that makes the most sense to you.**.

Set the 'Select source features from' to the larger dataset (using the same data from above, it will be the census tracts).

Click Vector menu, Spatial Query, and click Spatial Query.Also make sure the box next to Spatial Query Plugin is checked.

#QGIS DEFINE RASTER EXTENT INSTALL#

Type Spatial Query in the Search box, select Spatial Query, and click Install Plugin at the bottom of the screen.Go to the Plugins menu at the top of QGIS, and click 'Manage and Install Plugins.' You will need to add the Spatial Query plugin.You can remove the query by going back to the Query Builder and clearing the expression.Click OK to close the Query Builder and click OK to close the Layer Properties.Verify the Expression is 'STATE_FIPS' = '37'.Click the All button under the Values box and double click '37'.Click the = button under the Operators box.Double click the STATE_FIPS in the 'Fields' box.I want to use the 'States FIPS' field since this filed gives a unique number for each state and every census tract has a state FIPS number attached to it (North Carolina's FIPS number is 37).For this example, I have a shapefile that is nationwide census tracts and I want to query census tracts to North Carolina.Provider specific filter expression - where the expression is written out.

(ILIKE is the case insensitive version of LIKE.) For details, see the w3schools SQL Operators page. Values - when you click on a field, you can click on All to view all the values in that particular field.Fields - a list of all the fields/columns in the attribute table.There are 4 areas you will need to be concerned with:.In the lower-right hand corner click on the 'Query Builder' button.Open the Layer Properties of the layer you want to shrink by double-clicking the layer or right-click the layer and select 'Properties.'.

Qgis define raster extent