Opened 10 years ago

Last modified 4 years ago

#1688 assigned enhancement

ps.map: adding negative scale and offset to vpoints plotting -- patch provided

Reported by: alf Owned by: hamish
Priority: normal Milestone: 7.6.2
Component: Ps.map Version: svn-develbranch6
Keywords: ps.map vpoints Cc: grass-dev@…
CPU: Unspecified Platform: All

Description

Hello,

herein you find a patch that will enable negative scaling and introduces offset for vpoints representation in ps.map.

This will be useful if you are dealing with representation of vpoints symbols scaled by negative attribute values.

This patch introduces also the offset parameter in vpoints so it will be possible to shift the scaling values (useful when the values are both positive and negative).

In this patch documentation has be updated consequently.

please try the patch, revise improve and/or apply to GRASS! Best,

Alessandro Frigeri

Attachments (1)

ps.map-vpoints_negscale_and_offset.diff (4.1 KB ) - added by alf 10 years ago.
ps.map patch that introduces negative scaling and offset parameter to vpoints group

Download all attachments as: .zip

Change History (14)

by alf, 10 years ago

ps.map patch that introduces negative scaling and offset parameter to vpoints group

comment:1 by hamish, 10 years ago

Cc: grass-dev@… added
Owner: changed from grass-dev@… to hamish
Status: newassigned

comment:2 by hamish, 10 years ago

Milestone: 7.0.0

I know what you mean, but "offset" is perhaps not the best use for the word, people are likely to think of spatial offset of the map feature from its original x,y position, not offset in the y=mx+b slope & offset sense.

Can you provide an example of when this feature would be useful? (curious)

Hamish

comment:3 by neteler, 10 years ago

Cc: markus.neteler@… removed

in reply to:  2 comment:4 by alf, 10 years ago

Replying to hamish:

I know what you mean, but "offset" is perhaps not the best use for the word, people are likely to think of spatial offset of the map feature from its original x,y position, not offset in the y=mx+b slope & offset sense.

Can you provide an example of when this feature would be useful? (curious)

Thanks for the comment, Hamish. Imagine we would like to display points of acoustic measurements - with size proportional to the sound level referred to a certain threshold. Some of the measurements will be positive and some will be negative. To scale symbols accordingly we need to shift the measurements (or set the offset) so that we end up with all positive values.

Although this can be easily done within the db with some scripting, I though this would be a nice feature in ps.map (together with the negative scale option) - as it is mainly a visualization technique. Hope this make sense.

Regarding the terminology - I agree, offset in GIS is most commonly referred to horizontal coordinate shift. Maybe something like scaleoffset can maybe be more adequate for ps.map?

Alessandro

comment:5 by martinl, 7 years ago

Milestone: 7.0.07.0.5

comment:6 by martinl, 6 years ago

Milestone: 7.0.57.3.0

comment:7 by martinl, 6 years ago

Milestone: 7.3.07.4.0

Milestone renamed

comment:8 by neteler, 5 years ago

Milestone: 7.4.07.4.1

Ticket retargeted after milestone closed

comment:9 by neteler, 4 years ago

Milestone: 7.4.17.4.2

comment:10 by martinl, 4 years ago

What is the state of this issue?

comment:11 by martinl, 4 years ago

Milestone: 7.4.27.6.0

All enhancement tickets should be assigned to 7.6 milestone.

comment:12 by martinl, 4 years ago

Milestone: 7.6.07.6.1

Ticket retargeted after milestone closed

comment:13 by martinl, 4 years ago

Milestone: 7.6.17.6.2

Ticket retargeted after milestone closed

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