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Home - General / All posts - Clipping speed in Manifold V8 vs QGIS and other packages
dale

570 post(s)
#27-Nov-12 09:40

Has anyone tried testing mfd 8 on the Clipping Contest (ArcGis vs QGIS vs just about any other GIS )

Results shown posted so far have mfd 8 looking a little slow, albeit with caveats about comparable specs etc.

artlembo


3,135 post(s)
#28-Nov-12 17:56

I just ran it on my computer: i7, 3.06 Ghz., 64-bit, 12GB RAM.

Manifold (SQL): 14 minutes. (the select statement was about 35 seconds, but writing it to a table took most of the time).

Manifold (Transform): 18 minutes

Spatialite: 3 minutes (3:25)

Quantum 1.8: 3 minutes (3:05)

ArcGIS 10.1: 27 seconds

So, Manifold is not "a little slow", its VERY slow compared to free software. Also compared to ArcGIS it is about 40 times slower!

In looking over the website Dale provided, you can see that ArcGIS had some problems until ESRI made a few changes and fixed some bugs. ESRI should be commended for their responsiveness.

tjhb

9,551 post(s)
#28-Nov-12 18:53

How many of the other packages normalize topology or geometry within a clipping operation, as Manifold does?

ArcGIS doesn't, does it.

Of course, normalization usually doesn't matter much for contour lines, and it doesn't matter for competitions.

But that is not the general case in use.

artlembo


3,135 post(s)
#28-Nov-12 19:03

ESRI does its topology on-the-fly. Also, ArcGIS brought all the data in within about 2 seconds. Manifold takes a very long time to import the drawings. Quantum takes about 3 minutes, and spatialite takes about a minute.

BTW Tim, I think you would love spatialite. Really cool, and lightweight. This test also showed me that spatialite isn't a toy - it can handle some big data.

mdsumner


4,234 post(s)
#02-Dec-12 19:05

A follow up, of sorts:

http://gis.stackexchange.com/questions/42853/what-are-the-alternatives-to-manifold-gis


https://github.com/mdsumner

pcardoso


1,664 post(s)
#07-Dec-12 09:32

Nice

dale

570 post(s)
#02-Dec-12 22:53

There is a rather good description of the challenge on the Spatialite wiki with some interesting discussion on speed of the JTS algorithms, and on computing power in terms of ram vs CPU speed.

I miss the old days! This would have been a great discussion and a rant or two, coupled with a maintenance release down the track.

mdsumner


4,234 post(s)
#03-Dec-12 06:45

Thanks for the Spatialite link, that stuff is awesome


https://github.com/mdsumner

artlembo


3,135 post(s)
#03-Dec-12 12:46

yes, its really cool, and lightweight. Just remember, when you work with multiple layers, you are going to have to issue the index query. Manifold and PostGIS do this implicitly with the spatial index. For some reason, spatialite does not, so you have to explicitly reference that last part.

What I do is issue a create table query as:

CREATE TABLE ExampleTable AS SELECT......

then, before issuing a query I always use DROP TABLE ExampleTable

Manifold still makes this easier with SQL since you can link drawings really easily, or highlight selected features (you can use QGIS linked to spatialite, but its still an import). However, without a new product in 4 years I've had to start thinking about other options for spatial SQL.

rk
428 post(s)
#03-Dec-12 12:16

Manifold takes a very long time to import the drawings.

Interesting. For me it took under 20 sec.

I'm running 8.0.28. Do you?

8.0.28 release notes:

536. Importing a DBF file performs noticeably faster.

535. Importing a SHP file with complex metric performs noticeably faster.

I tried first to Normalize Metric, hoping it will mark geometries "clean" and speed up the clipping process, but unfortunately it didn't.

dale

570 post(s)
#04-Dec-12 00:20

rk, did you post your results? Looking at the posted import speeds of the other Manifold test, it looks like the user was not running 8.0.28.

joebocop
443 post(s)
#18-Dec-12 17:56

[deleted]

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