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Home - General / All posts - A little slow, should I have more RAM
#18-Apr-05 15:05

I have been reading through the forum trying to determine whether or not I am doing something wrong or if I should just try to break my boss down and purchase some more RAM. From some messages I've been reading, it seems as though this may be best solution. I've tried decreasing the precision and it helped, however I'm still finding that simple tasks such as zooming in take a very long time.

I'm running an AMD Athlon XP 3200+ 2.2 GHz, with 1 GB of RAM. However I am trying to extract certain slope percentages from a 10 meter DEM by using a query to create a drawing of the desired slopes. I have a 300 000 Hectare watershed and the DEM is split in to 5 tiles (surfaces). So in my project I have the five DEMs, and at this point, I have 2 point files of my selected slopes. It took 40 minutes to save the project and about 15 to simply zoom in to about a 1:10000 scale area on one of the point slope drawings. It also took another 20 to select a small square of points (about 60). Does this sound about right? Should this be taking so long? And do you think that purchasing another 512 or Gig of RAM would significantly increase the speed at which I am working. So far I am extremely satisfied with the functionality of Manifold, however some tasks are slowing me down quite a bit.

Thanks!

Ciao,

G.


Gloria Dangerfield, GIS/Database Coordinator Grey Sauble Conservation, ON Canada g.dangerfield@greysauble.on.ca

GIS Applications Specialist, Partner, Grey Bruce GeoSpatial

Dimitri


7,413 post(s)
#18-Apr-05 16:43

The key question is how large your DEMs are. It sounds like they are huge, so that the amount of data involved is very much larger than the RAM available, which means your process is paging out to disk all the time and thus is disk bound. Unless you can add enough RAM to avoid having to page out to disk (unlikely), adding RAM will not speed up the task a whole lot since it is disk-bound, not RAM bound.

Having said all that, well, adding RAM is almost always worth it because it will probably give a small speed increase anyway and, let's face it, RAM is cheap. If it was me I'd put in the max RAM the system can handle (probably 3GB total). Just like you can never be too thin or too rich, you can't ever have too much RAM. :-) And, there is a chance that your process will fall under the magic limit where everything fits into RAM and then it will go significantly faster than now.

Another approach is to increase the speed of your disk subsystem. There are several strategies here, such as mounting your TEMP folder on a large, fast drive, or perhaps using a RAID system with multiple hard disks configured into a single striped volume. Such techniques can easily increase your disk subsystem performance by a factor of four.

WillH


1,422 post(s)
#18-Apr-05 18:35

I've got RAID 0 SATA and it has some serious performance benefits.


Will Howell

rww2245 post(s)
#19-Apr-05 08:36

Gloria:

Just a thought - make sure you have unchecked the "show window contents while dragging" option in windows. See "Help-Contents-Read Me First". Probably won't make a big difference in your case, but Manifold recommends this for all applications.

Cheers,

RW

mao90210
84 post(s)
#25-Jul-16 04:27

Where can i find these in windows 7?

tjhb
10,094 post(s)
#25-Jul-16 04:31

Control Panel > System and security > System > Advanced system settings > Advanced tab > Performance > Settings > Visual Effects tab. (There are other ways to get here.)

Choose Custom. The "Show window contents while dragging" setting is near the bottom.

antoniocarlos

609 post(s)
#19-Apr-05 09:52

Hi Gloria

I'm not sure if you need to run a query. Why not run contour areas with the selected intervals on the slopes surface and see it it helps. I made these as tests.

Regards

Antonio


How soon?

#19-Apr-05 16:05

Thanks Antonio,

I tried this but when I tried running the contours and it took 92 hours to get to 36%. I ended up closing it. The query seems to run very quickly compared to most others processes I've run. I have used the contours before on this dataset when I created 1 meter contour lines. For some reason it didn't like the Area Between operator. I would like to be able to use this but at this point the query is working well for what I need.

Thanks Again,

G.

:-)


Gloria Dangerfield, GIS/Database Coordinator Grey Sauble Conservation, ON Canada g.dangerfield@greysauble.on.ca

GIS Applications Specialist, Partner, Grey Bruce GeoSpatial

antoniocarlos

609 post(s)
#19-Apr-05 16:20

No problem

Anybody. Would it make sense to be able to set the precision of the drawing prior to running the contours-area? To make things run faster.

Regards


How soon?

#28-Apr-05 16:20

I ended up splitting the contours up and they are working fine now. Also... today I installed another Gb of Ram (now I have 2 Gb) and things are running much much faster! :-)

I'm very happy with the purchase and am also finding that my splitting my Surfaces up from 4 to 10 surfaces speeds things up a great deal (even when they're all in the same project).

Ciao,

G.


Gloria Dangerfield, GIS/Database Coordinator Grey Sauble Conservation, ON Canada g.dangerfield@greysauble.on.ca

GIS Applications Specialist, Partner, Grey Bruce GeoSpatial

adamw


10,447 post(s)
#06-May-05 09:08

antoniocarlos - 2005-04-19 1:20 PM - Would it make sense to be able to set the precision of the drawing prior to running the contours-area? To make things run faster.

No. Extracting contours spends the bulk of the time analyzing pixel values and joining small portions of contour lines together. Both these things are precision-agnostic.

adamw


10,447 post(s)
#06-May-05 09:09

gloriadangerfield - 2005-04-18 12:05 PM - I am trying to extract certain slope percentages from a 10 meter DEM by using a query to create a drawing of the desired slopes.

Are you creating a point object for each pixel with the desired slope value? Would it make more sense to create areas covering the relevant pixels to keep the number of objects as low as possible? You could do this by a) using a query to select surface pixels with the desired slope values, b) saving the selection as a black-and-white image using Edit - Save Mask / Channel, and c) Shift-tracing the selection into one or more areas. This would be much faster.

#09-May-05 15:11

Actually, originally I had created point objects and realized that it was not what I wanted. So I used the Mask tool to create slopes from my DEM then I created contours of areas between and this worked perfectly. Before I doubled my RAM it ketp crashing or giving a No Memory error. Now it seems fine.

Cheers,

Gloria


Gloria Dangerfield, GIS/Database Coordinator Grey Sauble Conservation, ON Canada g.dangerfield@greysauble.on.ca

GIS Applications Specialist, Partner, Grey Bruce GeoSpatial

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