Python spatialite library app (sqlite3 extension)

Problem:

You need to read the content from the Spatialite library using Python, there is a Geometry field, and what is read is a string of binary bytes. The original code is attached:

ImportSqlite3conn= Sqlite3.connect ('./20059363.db') Cursor=Conn.execute ("SELECT ROWID, Object_pid, MESH, Trafsign_shape, Sign_type, GEOMETRY from Had_object_traffic_sign WHERE Trafsign_shap E = = 2"    "ORDER by ROWID") forRowinchcursor:Print(row[0])Print(row[1])    Print(Row[5])

The output is:

11833191183319b"\x00\x01\x00\x00\x00\x00\xeb\x1agy\x1c\xbc! A ' f\xef\xd4\x81\x00ha\x1d\xb0\xaby\x1f\xbc! a7\xfcnv\x82\x00ha|\xeb\x03\x00\x00\x01\x00\x00\x00\x05\x00\x00\x00\x1d\xb0\xaby\x1f\xbc! A7\xfcnv\x82\x00ha\x07\xb5\xdf\xda\[email protected]\xeb\x1agy\x1c\xbc! A ' F\xef\xd4\x81\x00ha\x07\xb5\xdf\xda\[email protected]\xeb\x1agy\x1c\xbc! A ' F\xef\xd4\x81\x00ha\xd8}\xc7\xf0\xd8\[email protected]\x1d\xb0\xaby\x1f\xbc! A7\xfcnv\x82\x00ha\xd8}\xc7\xf0\xd8\[email protected]\x1d\xb0\xaby\x1f\xbc! A7\xfcnv\x82\x00ha\x07\xb5\xdf\xda\[email protected]\xfe"

This third binary byte string is obviously problematic.

Process:

Ask a colleague later, say is a field that holds geographic information, need special method to decode.

Later query to a Astext method, you can read to the field's text? (In fact, I don't know what to read, the main field I don't understand what's written in it ...) ），

The SQL statement is like this:

" SELECT ROWID, Object_pid, MESH, Trafsign_shape, Sign_type, astext(GEOMETRY) from had_object_traffic_sign< c3/>ORDER by ROWID")

However, there is no Astest method in Sqlite3, so it needs to be extended.

This tutorial was found online: http://www.jianshu.com/p/5bc7d8b7b429, using the Python +spatialite + window solution, but didn't succeed ...

Later thought of a simple rough method, or according to this tutorial, the corresponding DLL, and then directly into the Python installation directory in the DLLs, and then modify the code:

ImportSqlite3conn= Sqlite3.connect ('./20059363.db') conn.enable_load_extension (True) conn.load_extension ('Mod_spatialite') Cursor=Conn.execute ("SELECT ROWID, Object_pid, MESH, Trafsign_shape, Sign_type, Astext (GEOMETRY) from Had_object_traffic_sign WHERE Trafs Ign_shape = = 2"    "ORDER by ROWID") forRowinchcursor:Print(row[0])Print(row[1])    Print(Row[5])

Output:

11833191183319POLYGON Z ((581135.737638 3145988.675262 105.977164, 581134.236871 3145987.663552 105.977164, 581134.236871 3145987.663552 104.060116, 581135.737638 3145988.675262 104.060116, 581135.737638 3145988.675262 105.977164))

Get.

The following is attached to a python3,64-bit DLL package, convenient for everyone to use.

Link: Http://pan.baidu.com/s/1gfioKZD Password: m23o

Python spatialite library app (sqlite3 extension)