; docformat = 'rst' ; ; NAME: ; cgShapeRange ; ; PURPOSE: ; Determines the X (longitude) and Y (latitude) data range of the entities in a shapefile. ; ;******************************************************************************************; ; ; ; Copyright (c) 2012, by Fanning Software Consulting, Inc. All rights reserved. ; ; ; ; Redistribution and use in source and binary forms, with or without ; ; modification, are permitted provided that the following conditions are met: ; ; ; ; * Redistributions of source code must retain the above copyright ; ; notice, this list of conditions and the following disclaimer. ; ; * Redistributions in binary form must reproduce the above copyright ; ; notice, this list of conditions and the following disclaimer in the ; ; documentation and/or other materials provided with the distribution. ; ; * Neither the name of Fanning Software Consulting, Inc. nor the names of its ; ; contributors may be used to endorse or promote products derived from this ; ; software without specific prior written permission. ; ; ; ; THIS SOFTWARE IS PROVIDED BY FANNING SOFTWARE CONSULTING, INC. ''AS IS'' AND ANY ; ; EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES ; ; OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT ; ; SHALL FANNING SOFTWARE CONSULTING, INC. BE LIABLE FOR ANY DIRECT, INDIRECT, ; ; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED ; ; TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; ; ; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ; ; ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ; ; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS ; ; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ; ;******************************************************************************************; ; ;+-------------------------------------------------------------------------- ; Determines the X (longitude) and Y (latitude) data range of the entities in a shapefile. ; ; :Categories: ; Utilities, Map Projections ; ; :Author: ; FANNING SOFTWARE CONSULTING:: ; David W. Fanning ; 1645 Sheely Drive ; Fort Collins, CO 80526 USA ; Phone: 970-221-0438 ; E-mail: david@idlcoyote.com ; Coyote's Guide to IDL Programming: http://www.idlcoyote.com ; ; :Examples: ; shapeBoundary = cgShapeRange('states.shp') ; ; :Returns: ; A four-element array containing the extent of the entity data in the ; shapefile, in the order [xrange[0], yrange[0], xrange[1], yrange[1]]. ; ; :Params: ; shapefile: in, optional, type=string ; The name of the shapefile for which you wish to know the extent. ; If not provided, the user will be asked to pick a shapefile. ; ; :Keywords: ; mean: out, optional, type=float ; A two-element float or double array giving the mean or average X value ; and the mean or average Y value of the entities in the shapefile, respectively ; median: out, optional, type=float ; A two-element float or double array giving the median X value ; and the median Y value of the entities in the shapefile, respectively ; xrange: out, optional, type=float ; A two-element float or double array giving the minimum and maximum ; extent of the shapefile entities in the X (longitude) direction, respectively ; yrange: out, optional, type=float ; A two-element float or double array giving the minimum and maximum ; extent of the shapefile entities in the Y (latitude) direction, respectively ; ; :History: ; Modification History:: ; Written by David W. Fanning by 29 August 2012. ; ; :Copyright: ; Copyright (c) 2012, Fanning Software Consulting, Inc. ;--------------------------------------------------------------------------- FUNCTION cgShapeRange, shapefile, $ MEAN=mean, $ MEDIAN=median, $ XRANGE=xrange, $ YRANGE=yrange Compile_Opt idl2 ; Return to caller on error. On_Error, 2 ; Need a shapefile? IF N_Elements(shapefile) EQ 0 THEN BEGIN shapefile = cgPickfile(Title='Select a SHAPEFILE...', Filter='*.shp') IF shapefile EQ "" THEN RETURN, FltArr(4) ENDIF ; Open the shape file and create the shape object. shapefileObj = Obj_New('IDLffShape', shapefile) IF Obj_Valid(shapefileObj) EQ 0 THEN $ Message, 'Unable to create shape file object. Returning...' ; Get all the attribute pointers from the file. These are the entities. entities = Ptr_New(/Allocate_Heap) *entities = shapefileObj -> GetEntity(/All, /Attributes) ; Get the entity data ranges. entityMinX = FltArr(N_Elements(*entities)) entityMaxX = FltArr(N_Elements(*entities)) entityMiny = FltArr(N_Elements(*entities)) entityMaxY = FltArr(N_Elements(*entities)) FOR j=0,N_Elements(*entities)-1 DO BEGIN thisEntity = (*entities)[j] entityMinX[j] = thisEntity.bounds[0] entityMaxX[j] = thisEntity.bounds[4] entityMiny[j] = thisEntity.bounds[1] entityMaxY[j] = thisEntity.bounds[5] ENDFOR xrange = [Min(entityMinX), Max(entityMaxX)] yrange = [Min(entityMinY), Max(entityMaxY)] ; Need mean values? IF Arg_Present(mean) THEN BEGIN xmean = Mean([entityMinX, entityMaxX]) ymean = Mean([entityMinY, entityMaxY]) mean = [xmean, ymean] ENDIF ; Need median values? IF Arg_Present(median) THEN BEGIN xmedian = Median([entityMinX, entityMaxX]) ymedian = Median([entityMinY, entityMaxY]) median = [xmedian, ymedian] ENDIF ; Clean up. Obj_Destroy, shapefileObj Ptr_Free, entities ; Return the extent of the data. RETURN, [xrange[0], yrange[0], xrange[1], yrange[1]] END