Extract latitudes and longitudes from shapefiles

[vww82]

Hi,

how can I extract the lat&lon of every point of every shape in your shapefiles?

Alternatively, could you send me a textfile containing this information for a specific shape-file?

I browsed the web but it seems impossible to obtain this data from shp-files.

Thanks a lot in advance

Ben

[pushframework]

It is not impossible. I managed to decode all polygons for the purpose of rendering a map.

Ask me which shape-file and the output format and i’ll send the result to you.

[Nathaniel]

Use a tool like OGR2OGR:

http://www.gdal.org/ogr2ogr.html

[vww82]

Thanks for the help, I managed to do it with Java and OpenMap. Quite a pain, though

[nigel]

Can anyone help me with the format of the blobs in the SQLite data. For example, if I open up the first record in ne_10m_lakes, the second column ‘geometry’ contains 637 bytes, the first 16 of which are:

01 03 00 00 00 01 00 00 00 27 00 00 00 08 28 27 41

after which a pattern of 32 bit ints appears to begin.

According to Wikipedia(http://en.wikipedia.org/wiki/Shapefile), a shapefile begins with ‘File code (always hex value 0x0000270a)’, so I guess the blob data does not start at the beginning of the shape data, but I can’t figure out the exact format.

 

[nigel]

Getting somewhere. Not sure what the first byte is. Next 4 bytes=shape type (3=polygon)Next 4 bytes = record number (1) next 4 bytes are record length(0x27=39decimal) and the data starts at 08 28 27 41. Slightly different to the shapefile format, but not by much.

[Author]

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