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Displaying posts with tag: GIS (reset)
MySQL 8.0 GIS Units of Measure - Meter, foot, Clarke's yard, or Indian Foot

The ST_DISTANCE function has been upgraded in MySQL 8.0.16 to allow you to specify the unit of measure between to locations.  Previously you had to convert from meters to what you desired but now you can use the INFORMATION_SCHEMA.ST_UNITS_OF_MEASURE table to help you get many of the more popular measurements (foot, yard, statue mile, nautical mile, fathom) and some ones that are new to me (chain, link, various feet).   However some measures are omitted (furlong,smoot) that may have some relevance in your life.

select * from information_schema.ST_UNITS_OF_MEASURE;
Fetching table and column names from `mysql` for auto-completion... Press ^C to stop.
| UNIT_NAME    …

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MySQL Workbench Spatial Viewer or How to See your GEOMETRY Data

The past couple of blog entries have been on Geographic Information Systems and Geometric Data.  Visualizing that data with MySQL Workbench makes it easier for me to see what the results really mean.

Workbench 8.0.15 will draw the polygon with the Spatial View Option

So how do you get there?

Start Workbench, create a new SQL Tab in your favorite scratch schema, and crate the table below. 

  PRIMARY KEY (`id`));

Next add some data.


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MySQL 8.0 GIS -- Inserting Data & Fun Functions

The last blog entry was very popular and there were lots of requests for some introductory information on the spatial data types. 

Well Known Text Or Binary
I am going to use the GEOMETRY data type over POINT, LINESTRING, or POLYGON as it can store any of those three while the other three can only contain data matching their name (so POINT can holds only point data, etc.). The values are stored in an internal geometry format but it takes wither WKT or WKB formatted data.

Those are Well-Known Text (WKT) or Well-Known Binary (WKB) formats repectively. I am hoping most of your are better with text than binary so the following examples demonstrate how to insert geometry values into a table by converting WKT values to internal geometry format.

So let us start with a …

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MySQL 8.0 Geographic Information Systems (GIS) - How to get the distance between two cities

MySQL before version 5.7 had less than stellar Geographic Information Systems (GIS) support.  In version 5.7 the Boost.Geometry two dimensional or 2D libraries were added.  And with 8.0 came the three dimensional or 3D libraries. But how do you use these features?

I would like to state up front that this is all new to me and this is an attempt for me to document what it takes to go from zero knowledge on GIS to something hopefully better.  What I want to do as an exercise is to get the distance between two places from their longitude and latitude, say two cities near where I live.  So what do we have to do to accomplish that?

It is actually easy with the functions provided if we have the longitude and latitude in an SRID 4326 format.

SELECT ST_Distance(
 (SELECT loc FROM cities WHERE name = 'Trondheim'),
 (SELECT loc FROM cities WHERE …

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Upgrading to MySQL 8.0 with Spatial Data

The big change from MySQL 5.7 to 8.0 when it comes to spatial data, is the support for multiple spatial reference systems and geographic computations. This means that the SRIDs of geometries actually have meaning and affect computations. In 5.7 and earlier, however, the SRIDs are ignored, and all computations are Cartesian.…

Detecting Incompatible Use of Spatial Functions before Upgrading to MySQL 8.0

There are many changes to spatial functions in MySQL 8.0:

The first two are failing cases.…

Creating Your Own Spatial Reference Systems in MySQL 8.0

MySQL 8.0.11 comes with a catalog of 5108 spatial reference systems (SRSs). 4628 projections (flat maps), 479 geographic (ellipsoidal) representations of Earth, and one Cartesian all-purpose abstract plane (SRID 0). And if for some reason that isn’t enough, we can create our own.…

Upgrading Spatial Indexes to MySQL 8.0

MySQL has had spatial indexes for many years, but they have all been Cartesian (X and Y coordinates) indexes. MySQL 8.0 adds support for geographic (latitude-longitude) indexes. In an earlier blog post, I described how the feature works. In this post, we’ll go into the details of how to upgrade from 5.7 to 8.0 if you have spatial indexes.…

Projected Spatial Reference Systems in MySQL 8.0

MySQL 8.0.11 comes with a catalog of 5108 spatial reference system (SRS) definitions. In a previous post, we covered the definitions of geographic SRSs. In this post we’ll go into the details of projected SRSs. (If you haven’t done so already, I suggest you read the previous post first.)

Projected SRSs are flat, Cartesian coordinate systems created by projecting points on (an oblate spheroidal model of) Earth onto a flat surface.…

Geographic Spatial Reference Systems in MySQL 8.0

MySQL 8.0.11 comes with a catalog of 5108 spatial reference system (SRS) definitions, and 479 of these are geographic. We usually just refer to them by SRID, but in this blog post we’ll dive into the details and try to understand the definition itself.…

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