Delaware Wetland Video Series

Written by charlie   
Tuesday, 19 January 2016 02:20
Delaware's Department of Natural Resources and Environmental Control (DNREC) just released its fifth wetland related video as part of the “Wetlands 101” video series - “Restoring Wetlands: Facing Challenges” on DNREC’s YouTube Channel.

“Restoring Wetlands: Facing Challenges” focuses on common problems that wetlands face, and what Delawareans can do to help restore wetlands' natural capabilities. The five-minute video features four items that impair wetlands, interesting facts, scenic views, and live wetland wildlife.

The entire playlist of 5 wetlands related videos is here and includes:
  • Wetlands 101 - What is a Wetland?
  • Wetlands 101 - 3Ps
  • Wetlands 101: Wetlands & Sea Level Rise
  • Wetlands 101: Wild Wetlands
  • Wetlands 101 - Restoring Wetlands Part 1: Facing Challenges

There are also additional wetlands related videos including one on beach grass planting produces the the DNREC.

Recovering an old MediaWiki Database

Written by charlie   
Friday, 15 January 2016 15:56
In 2011, I permanently shut down the Wetland Wiki, as the workload of constantly editing and updating the pages became onerous, and Wikipedia had much of the same, if less detailed, information. Before shutting it down, I copied the Mediawiki (Version 1.13.1) database for posterity, and occasionally thought that some of the pages/articles I wrote should not have just disappeared, but been shared in some other fashion. 5 years later, almost to the day, I tried importing the database, and ran into many unforeseen errors, primarily due to depreciated syntax and changes in MySQL - my database hadn’t changed, but the MySQL has changed enough to make importing the database impossible without some updates.

Below are the errors I encountered while importing them into PhpMyAdmin, and how I fixed them; maybe someone else will find them useful. These few changes allowed me to import the 25MB database with approximately 200,000 lines successfully. The first error I encountered was:

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'TYPE=MyISAM' at line 8.

'TYPE=MyISAM' is depreciated, so I searched and replaced over 20 occurrences with "ENGINE=MyISAM". In a closely related error, 'TYPE=InnoDB" was also replaced with "ENGINE=InnoDB".

At this point about 20% of the database was imported successfully until the following error:

#1426 - Too big precision 14 specified for 'cl_timestamp'. Maximum is 6. which was easily corrected to timestamp(6) CREATE TABLE `categorylinks` (
`cl_from` int(8) unsigned NOT NULL default '0',
`cl_to` varchar(255) binary NOT NULL default '',
`cl_sortkey` varchar(86) binary NOT NULL default '',
`cl_timestamp` timestamp(14) NOT NULL,
UNIQUE KEY `cl_from` (`cl_from`,`cl_to`),
KEY `cl_timestamp` (`cl_to`,`cl_timestamp`),
KEY `cl_sortkey` (`cl_to`,`cl_sortkey`,`cl_from`)

The last error recieved was, #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'TYPE=HEAP MAX_ROWS=25000' at line 3. Which I updated to 'ENGINE=HEAP MAX_ROWS=25000'

Additionally, PhpMyAdmin had been timing out while importing the database after a few minutes. To lengthen the amount of time available for the import, I added the following line $cfg['ExecTimeLimit'] = 6000; to and restarted Apache.

After all this, the entire 25MB database was imported successfully. Now all I have to do is extract the articles, but that’s for another post!
Last Updated on Friday, 15 January 2016 16:39

GIS Presentations

Written by charlie   
Thursday, 14 January 2016 19:44
I found the following Open Source GIS related presentations written by GreenWood map over the past 2 years informative, especially the Parcel Mapping complexities found in Wyoming.
  • Skeletonizing Polygons Using PostGIS
  • Cartography and Topology
  • Parcel Mapping WyGEO Meeting
  • Simplifying Geomoetries Using Open Source Tools
The presentations are available on the Greenwood website.
Last Updated on Thursday, 14 January 2016 19:48
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