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82 lines
3.5 KiB
Markdown
82 lines
3.5 KiB
Markdown
```python
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#!python
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from awips.dataaccess import DataAccessLayer
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from shapely.geometry import Polygon,Point
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from datetime import datetime
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#Initiate a new DataRequest
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#Get all of the states from the database
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print "Requesting all states from DAF"
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t1=datetime.utcnow()
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request = DataAccessLayer.newDataRequest()
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request.setDatatype("maps")
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request.addIdentifier("geomField","the_geom")
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request.addIdentifier("table","mapdata.states")
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request.setParameters("state","fips","name")
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states = DataAccessLayer.getGeometryData(request, None)
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t2=datetime.utcnow()
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tdelta = t2-t1
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print 'DAF query to get all states took %i.%i seconds' %(tdelta.seconds,tdelta.microseconds)
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#Create a polygon object...for example this is a polygon around Oklahoma City
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polygon = Polygon([(-97.82,35.63),(-97.21,35.63),(-97.21,35.15),(-97.82,35.15),(-97.82,35.63)])
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#Now lets filter the states down to the one that contains the above polygon
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#We will use the python built in filter method to accomplish this
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#the expression below goes through each state object, gets it's geometry, and calls
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#it's contains method. It in essence creates a new list, state_contain_polygon, with
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#only the states where the contains method evaluates to true.
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t1=datetime.utcnow()
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state_contain_polygon = filter(lambda state: state.getGeometry().contains(polygon),states)
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t2= datetime.utcnow()
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tdelta = t2-t1
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print '\nFilter state objects to one that contains polygon took %i.%i seconds' %(tdelta.seconds,tdelta.microseconds)
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print state_contain_polygon
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print "Polygon is in the state of",state_contain_polygon[0].getString('name')
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#Lets also create a point object...this one is located in the state of Iowa
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point = Point(-93.62,41.60)
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#Now lets see what state our point is in
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t1=datetime.utcnow()
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state_contain_point = filter(lambda state: state.getGeometry().contains(point),states)
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t2= datetime.utcnow()
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tdelta = t2-t1
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print '\nFilter state objects to one that contains point took %i.%i seconds ' %(tdelta.seconds,tdelta.microseconds)
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print state_contain_point
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print "Point is in the state of",state_contain_point[0].getString('name')
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#One last example...this time for an intersection. Lets find all of the states this polygon intersects
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#This polygon is the same as above just extended it further south to 33.15 degrees
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polygon2 = Polygon([(-97.82,35.63),(-97.21,35.63),(-97.21,33.15),(-97.82,33.15),(-97.82,35.63)])
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t1=datetime.utcnow()
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state_intersect_polygon = filter(lambda state: state.getGeometry().intersects(polygon2),states)
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t2= datetime.utcnow()
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tdelta = t2-t1
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print '\nFilter state objects to the ones that intersect polygon took %i.%i seconds ' %(tdelta.seconds,tdelta.microseconds)
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print state_intersect_polygon
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for state in state_intersect_polygon:
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print "Polygon intersects the state of",state.getString('name')
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```
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```python
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Requesting all states from DAF
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DAF query to get all states took 21.915029 seconds
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```
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```python
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Filter state objects to one that contains polygon took 0.382097 seconds
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[<awips.dataaccess.PyGeometryData.PyGeometryData object at 0x2bebdd0>]
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Polygon is in the state of Oklahoma
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```
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```python
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Filter state objects to one that contains point took 0.2028 seconds
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[<awips.dataaccess.PyGeometryData.PyGeometryData object at 0x2beb9d0>]
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Point is in the state of Iowa
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```
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```python
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Filter state objects to the ones that intersect polygon took 0.4032 seconds
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[<awips.dataaccess.PyGeometryData.PyGeometryData object at 0x2beb610>, <awips.dataaccess.PyGeometryData.PyGeometryData object at 0x2bebdd0>]
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Polygon intersects the state of Texas
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Polygon intersects the state of Oklahoma
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```
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