How do you find the geographic size in meters given a lower left coordinate and upper right coordinate. The projection would be WGS84 projection. Ex. 33,-119,35,-117. What would be the area in meters that covers?
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The answer depends on the units -- I assume you are giving latitude/longitude in degrees here?– EricaCommented Aug 4, 2014 at 13:28
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Yes WGS84 is correct.– inspirationCommented Aug 4, 2014 at 13:28
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The answer will also depend on what Projected Coordinate System you choose to project into. Would you be able to edit your question to specify that, please?– PolyGeo ♦Commented Aug 4, 2014 at 13:31
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1 Answer
So, with ArcMap, from ESRI Forums:
Private Function PolygonFromEnvelope(pEnv As IEnvelope) As IPolygon
Dim pPtColl As IPointCollection
Set pPtColl = New Polygon
With pPtColl
.AddPoint pEnv.LowerLeft
.AddPoint pEnv.UpperLeft
.AddPoint pEnv.UpperRight
.AddPoint pEnv.LowerRight
'Close the polygon
.AddPoint pEnv.LowerLeft
End With
Set PolygonFromEnvelope = pPtColl
End Function
then Measure Area (ArcMAP 10.2)
or maybe using GDAL/OGR:
from osgeo import ogr
def my_envelope(geom):
(minX, maxX, minY, maxY) = geom.GetEnvelope()
# Create ring
ring = ogr.Geometry(ogr.wkbLinearRing)
ring.AddPoint(minX, minY)
ring.AddPoint(maxX, minY)
ring.AddPoint(maxX, maxY)
ring.AddPoint(minX, maxY)
ring.AddPoint(minX, minY)
# Create polygon
poly_envelope = ogr.Geometry(ogr.wkbPolygon)
poly_envelope.AddGeometry(ring)
return poly_envelope
then calculate the polygon area (QGIS) or OGR get_area() although I'm not well-versed on GDAL/OGR so I'm not sure how it takes into account the coordinate system. QGIS should calculate with the projection in mind.
