Parsing Geometry MySQL's Field

[Silver]

Hello friends,
I have a MySQL table for storing polygons for each country's state.
---
idregion, int, autoincrement
region, varchar(50)
polygon: geometry
---

From PHP I'm getting a json response with the polygon coordinates as
string:
"SELECT region, AsText(polygon) FROM regions"
Like this:
[{'region':'state 1','polygon':'POLYGON(5 3,8 4,5 5,2 9)'},
{'region':'state 2','polygon':'POLYGON(2 3,7 1,9 7,1 3)'},...]

Now, for showing the polygon using the Google Maps API I need to
remove the first portion of the string and parse the rest twice for
creating a LatLng set.

Can somebody suggest to me a best way for creating a polygon from a
GEOMETRY MySQL field?
Regards!!!!

[Chris Broadfoot]

Some of these may be of use...

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/indexOf

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/substring

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/split

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/parseFloat

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[Silverio Lora Milanes]

Hello Chris, thanks by your answer but I think I didn't explain myself properly.

Currently the application is working property and I’m loading from MySQL the polygons information and I’m showing its in Google Maps, but… I have performance problems because I’m parsing with Javascript very long strings and I need to know about a better way for doing it.

My actual procedure is:

-          MySQL table with Geometry field (spatial extension)

-          Query it, using AsText(geometry) function

-          Send it to javascript in json format

-          Parse the string and separate each polygon’s node for creating an array of LatLng

-          Using google.maps.Polyline

Note:

I can’t use Postgres and PostGIS in my server.  

 

Some suggestion?

[Chris Broadfoot]

Aha - perhaps some server-side processing would be good here.

If you could return the geometry as an array of floats, that would cut out most of your parsing time in JS.

I suggest you change your pipeline to:

-          MySQL table with Geometry field (spatial extension)

-          Query it, using AsText(geometry) function

-          Parse geometry into array of floats

-          Send it to javascript in json format

-          Create an array of LatLng

-          Using google.maps.Polyline

If that doesn't help, there may be some more improvements possible, such as storing a json representation alongside the MySQL geometry upon write.

Chris

[Jason Sanford]

I'm not sure if mysql has the same st_asgeojson function as PostGIS but if it does, I've been working on a utility to convert GeoJSON objects (Point, LineString, Polygon) to Google Maps Vectors (Marker, Polyline, Polygon). This way you'd be dealing with native JavaScript objects instead of parsing a gigantic string.

https://github.com/JasonSanford/GeoJSON-to-Google-Maps

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[ɑhmɑd ɑzimi]

Hi Jason,

cool library, but what about performance? Is it good idea to parse this kinds of data on clients?

Or is it better to do this on server?