posgresql的schema

https://postgis.net/workshops/postgis-intro/schemas.html

shp2pgsql-how-to-know-the-schema-table

shp2pgsql      [<options>]     <shapefile>     [[<schema>.]<table>]

SQL Multiple Joins Work just like Single Joins

Multiple Joins Work just like Single Joins

a-visual-explanation-of-sql-joins

https://www.dofactory.com/sql/join

PostGIS – How to convert multipolygon geometry into polygon geometry

http://www.codedirection.com/convert-multipolygon-geometry/

postgis-convert-multipolygon-to-single-polygon

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。

qgis geojson bug

Edits in GeoJson datasources are not saved anymore

QGIS saves geojson.tmp instead of updating file

vim与系统剪贴板

how-can-i-copy-text-to-the-system-clipboard-from-vim

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. 

qgis topology checker

topology_checker

how-to-find-all-points-within-polygon-in-postgis

postgis-st-within-and-a-join

plugins_geometry_checker

https://postgis.net/workshops/postgis-intro/joins.html

how-to-find-points-within-a-polygon-in-postgis

qgis-db-manager-load-new-layer-not-loading-sql-query

Difference between Feature and Geometry

Difference between Feature and Geometry

Difference between map layer and spatial dataset (e.g. feature class, shapefile)?

https://www.qgistutorials.com/en/docs/3/nearest_neighbor_analysis.html

Point Annotation to Text in CAD

Point Annotation to Text in CAD

ogr dxf driver

ogr-dxf-driver

https://gdal.org/programs/ogr2ogr.html

https://gdal.org/drivers/vector/dxf.html

Excel VBA

range

excel.range.end

Q-MAT: Computing Medial Axis Transform by Quadratic Error Minimization

Q-MAT: Computing Medial Axis Transform by Quadratic Error Minimization

https://github.com/libigl/libigl/issues/229

Creating a Medial Axis for a Polygon

Point in polygon

https://en.wikipedia.org/wiki/Point_in_polygon

stackoverflow

https://github.com/substack/point-in-polygon

计算几何

geometrictools

SVG

在线svg编辑器

svgwrite

https://github.com/mozman/svgwrite

https://www.w3.org/TR/SVG11/shapes.html#PolygonElement

法线

法线---维基百科

法线贴图(Normal Mapping)

learn opengl

C++ typename的起源与用法

C++ typename的起源与用法

std::vector::pop_back

openmesh

http://www.openmesh.org/intro/

mesh结构的基本使用

OpenMesh的进阶用法

OpenMesh译稿：使用并理解OpenMesh-迭代器与循环器

http://www.openmesh.org

New property interface

How to save custom vertex properties with openmesh in Python?

qgis 水文分析

beautiful-watershed-polygons-in-qgis

Hydrological analysis

How to take buffer and create watershed and calculate volume of reservoir in QGIS

measuring-volumes-using-dems

how-to-calculate-a-volume-terrain-with-qgis3-tutorial

ArcGIS水文分析实战教程

ArcGIS水文分析实战教程

ArcGIS水文分析实战教程（1）GIS与水文学

多边形面积计算

任意多边形面积计算（用于任意水位的非规则河道截面积计算）

计算任意多边形的面积

The Definitive, Non-Technical Introduction to LaTeX

The Definitive, Non-Technical Introduction to LaTeX

英特尔CPU的命名规则

英特尔CPU的命名规则