55 lines
1.9 KiB
Python
Executable file
55 lines
1.9 KiB
Python
Executable file
#!/usr/bin/env python
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# Utility to interrogate ESRI shape files
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import os
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import sys
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import struct
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if __name__ == "__main__" :
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if len(sys.argv) !=2:
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print>>sys.stderr, "Usage:",sys.argv[0],"<shapefile>"
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sys.exit(1)
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shx_filename = sys.argv[1][:-3]+"shx"
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shp_filename = sys.argv[1][:-3]+"shp"
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shx = open(shx_filename)
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shp = open(shp_filename)
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header = (struct.Struct(">IIIIIII"),struct.Struct("<IIdddddddd"))
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# SHX header
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_,_,_,_,_,_,shx_file_length = header[0].unpack_from(shx.read(28))
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_,_,lox,loy,hix,hiy,_,_,_,_ = header[1].unpack_from(shx.read(72))
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# SHP header
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_,_,_,_,_,_,shp_file_length = header[0].unpack_from(shp.read(28))
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_,_,lox,loy,hix,hiy,_,_,_,_ = header[1].unpack_from(shp.read(72))
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print "SHX FILE_LENGTH=",shx_file_length,"bytes"
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print "SHP FILE_LENGTH=",shp_file_length,"bytes"
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print "BBOX(",lox,loy,hix,hiy,")"
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record_header = struct.Struct(">II")
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record = struct.Struct(">II")
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calc_total_size = 50
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count = 0
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while shx.tell() < shx_file_length * 2 :
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offset,shx_content_length = record.unpack_from(shx.read(8))
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shp.seek(offset*2, os.SEEK_SET)
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record_number,content_length = record_header.unpack_from(shp.read(8))
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#print (2*offset),record_number,content_length
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if shx_content_length <> content_length:
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print "BAD SHAPE FILE: content_lenght mismatch in SHP and SHX",shx_content_length,content_length
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sys.exit(1)
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calc_total_size +=(4 + content_length)
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count+=1
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print "SHAPES COUNT=",count
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delta = shp_file_length-calc_total_size
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if delta > 0 :
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print "BAD SHAPE FILE: extra ", 2*(shp_file_length-calc_total_size),"bytes"
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elif delta < 0:
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print "BAD SHAPE FILE: missing ", 2*(shp_file_length-calc_total_size),"bytes"
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else:
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print "SHAPE FILE IS GOOD!"
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