shp2pgsql-how-to-know-the-schema-table
shp2pgsql [<options>] <shapefile> [[<schema>.]<table>]
2019年8月25日星期日
posgresql的schema
https://postgis.net/workshops/postgis-intro/schemas.html
shp2pgsql-how-to-know-the-schema-table
shp2pgsql [<options>] <shapefile> [[<schema>.]<table>]
shp2pgsql-how-to-know-the-schema-table
shp2pgsql [<options>] <shapefile> [[<schema>.]<table>]
2019年8月19日星期一
2019年8月18日星期日
使用qgis对dxf文件进行几何检查
1 将dxf文件转换为geojson文件
使用ogr2gor将dxf文件转换为geojson文件：
ogr2ogr -dim XY -skipfailures -f "GeoJSON" test.json by_aka2020.dxf
2 用qgis打开geojson文件，注意导入后要指定投影坐标系
① qgis的文件浏览器好像不支持json文件，需要使用“打开数据源管理器”按钮。
②在qgis的插件管理器中，启用“几何检查器”，启用后，在菜单Vector中寻找“几何检查器”。
③ qgis的“几何检查器”无法处理多段线中“短线段”问题。
④ arcmap也有几何检查的功能，但是不能指定“短线段”的长度范围。
postgresql 中的大小写
why-postgresql-does-not-like-uppercase-table-names
are-function-names-in-postgresql-case-insensitive
Are PostgreSQL column names case-sensitive?
how-do-i-list-all-columns-for-a-specified-table
In PostgreSQL, names of identifiers are always folded to lowercase unless you surround the identifier name with double quotes.
you are advised to always quote a particular name or never quote it.
Which basically means all the queries in postgres are by default converted to lowercase letters. But, If you want to create a column with Upper case letters then you must specify it inside the "". And get the data of in uppercase Column(DETAILS), you need to specify the column name in (double-quotes)"". So that postgres treats the data in quotes as Case-sensitive and gives the expected column(DETAILS) values.
are-function-names-in-postgresql-case-insensitive
Are PostgreSQL column names case-sensitive?
how-do-i-list-all-columns-for-a-specified-table
In PostgreSQL, names of identifiers are always folded to lowercase unless you surround the identifier name with double quotes.
you are advised to always quote a particular name or never quote it.
Which basically means all the queries in postgres are by default converted to lowercase letters. But, If you want to create a column with Upper case letters then you must specify it inside the "". And get the data of in uppercase Column(DETAILS), you need to specify the column name in (double-quotes)"". So that postgres treats the data in quotes as Case-sensitive and gives the expected column(DETAILS) values.