Prioritising polygons in QGIS
Clash Royale CLAN TAG#URR8PPP
I just created a layer in which I hand drew a lot of polygons.
Now I want to fill out the Attribute table through commands since it will save me a bunch of time.
Therefore, I calculated the area of each polygon using $area/10000 to have the size in ha.
I want to prioritize each area
- above 10 ha as Prio 1
- each below 1 ha as Prio 3
- each in between as Prio 2
Does anyone have a smart solution to the problem?
My closest approach is: IF ("Size ha" > 10, 1, 2)
That however still leaves me with having to distinguish the areas of Prio 2 to Prio 3 manually.
qgis polygon attribute-table command-line
asked Feb 26 at 10:18
Philip GatzlaffPhilip Gatzlaff
243
add a comment |
I just created a layer in which I hand drew a lot of polygons.
Now I want to fill out the Attribute table through commands since it will save me a bunch of time.
Therefore, I calculated the area of each polygon using $area/10000 to have the size in ha.
I want to prioritize each area
- above 10 ha as Prio 1
- each below 1 ha as Prio 3
- each in between as Prio 2
Does anyone have a smart solution to the problem?
My closest approach is: IF ("Size ha" > 10, 1, 2)
That however still leaves me with having to distinguish the areas of Prio 2 to Prio 3 manually.
qgis polygon attribute-table command-line
asked Feb 26 at 10:18
Philip GatzlaffPhilip Gatzlaff
243
Just a general annotation: The expamples given on the different tools in the field calculator are quite useful to picture, how the tools work.
– Erik
Feb 26 at 10:25
add a comment |
I just created a layer in which I hand drew a lot of polygons.
Now I want to fill out the Attribute table through commands since it will save me a bunch of time.
Therefore, I calculated the area of each polygon using $area/10000 to have the size in ha.
I want to prioritize each area
- above 10 ha as Prio 1
- each below 1 ha as Prio 3
- each in between as Prio 2
Does anyone have a smart solution to the problem?
My closest approach is: IF ("Size ha" > 10, 1, 2)
That however still leaves me with having to distinguish the areas of Prio 2 to Prio 3 manually.
qgis polygon attribute-table command-line
asked Feb 26 at 10:18
Philip GatzlaffPhilip Gatzlaff
243
I just created a layer in which I hand drew a lot of polygons.
Now I want to fill out the Attribute table through commands since it will save me a bunch of time.
Therefore, I calculated the area of each polygon using $area/10000 to have the size in ha.
I want to prioritize each area
- above 10 ha as Prio 1
- each below 1 ha as Prio 3
- each in between as Prio 2
Does anyone have a smart solution to the problem?
My closest approach is: IF ("Size ha" > 10, 1, 2)
That however still leaves me with having to distinguish the areas of Prio 2 to Prio 3 manually.
qgis polygon attribute-table command-line
qgis polygon attribute-table command-line
asked Feb 26 at 10:18
Philip GatzlaffPhilip Gatzlaff
243
asked Feb 26 at 10:18
Philip GatzlaffPhilip Gatzlaff
243
edited Mar 7 at 6:48
Philip Gatzlaff
asked Feb 26 at 10:18
Philip GatzlaffPhilip Gatzlaff
243
asked Feb 26 at 10:18
Philip GatzlaffPhilip Gatzlaff
243
asked Feb 26 at 10:18
Philip GatzlaffPhilip Gatzlaff
243
243
Just a general annotation: The expamples given on the different tools in the field calculator are quite useful to picture, how the tools work.
– Erik
Feb 26 at 10:25
add a comment |
Just a general annotation: The expamples given on the different tools in the field calculator are quite useful to picture, how the tools work.
– Erik
Feb 26 at 10:25
Just a general annotation: The expamples given on the different tools in the field calculator are quite useful to picture, how the tools work.
– Erik
Feb 26 at 10:25
Just a general annotation: The expamples given on the different tools in the field calculator are quite useful to picture, how the tools work.
– Erik
Feb 26 at 10:25
add a comment |
3 Answers
3
active
oldest
votes
This should work
if($area/10000 > 10,1,if($area/10000 < 1,3,2))
Just a capsuled if-condition, first checking for areas greater 10 ha, then checking for those smaller than 1 ha, then giving everything else prio 2.
answered Feb 26 at 10:22
ErikErik
3,323322
add a comment |
CASE
WHEN "Size ha" >= 10 THEN 'Prio 1'
WHEN "Size ha" > 1 AND "Size ha" < 10 THEN 'Prio 2'
WHEN "Size ha" <= 1 THEN 'Prio 3'
END
Or as was provided by @Erik, the upper formula can be rewritten as
if("Size ha" >= 10, 'Prio 1', if("Size ha" <= 1, 'Prio 3', 'Prio 2'))
References:
- Expressions | Conditionals
- Elseif Conditional Statement in QGIS Field Calculator
answered Feb 26 at 10:22
TarasTaras
2,2992727
Ah, thanks. I tried using WHEN clauses, but somehow didnt end up at a fitting result. My command looked different though. I will try it out!
– Philip Gatzlaff
Feb 26 at 10:23
Another possbile solution, though I do not like doublechecks on conditions, they tend to be a bit complicated in my experience.
– Erik
Feb 26 at 10:23
1
@Taras that is my own judgement, I usually mess up conditions when having to check upper and lower boundaries ;-)
– Erik
Feb 26 at 10:32
1
@Erik, I think I will happen to me as well. However, when I have for instance 20 conditions I will be lost within a number of parenthesis in If-condition :-)
– Taras
Feb 26 at 10:35
1
Just create a new column and fill it with CASE formula.
– Taras
Feb 26 at 10:39
|
show 3 more comments
CASE
WHEN "Size ha" =>10 THEN 'Prio 1' for the area above 10 ha
WHEN "Size ha" <10 AND "Size" >1 THEN 'Prio 2' for the area between 10 ha to 1 ha
WHEN "Size ha" <1 THEN 'Prio 3' for the area below 1 ha
END
Use the code to update the priority field.
answered Mar 19 at 9:00
Alvin KomenAlvin Komen
11
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
This should work
if($area/10000 > 10,1,if($area/10000 < 1,3,2))
Just a capsuled if-condition, first checking for areas greater 10 ha, then checking for those smaller than 1 ha, then giving everything else prio 2.
answered Feb 26 at 10:22
ErikErik
3,323322
add a comment |
This should work
if($area/10000 > 10,1,if($area/10000 < 1,3,2))
Just a capsuled if-condition, first checking for areas greater 10 ha, then checking for those smaller than 1 ha, then giving everything else prio 2.
answered Feb 26 at 10:22
ErikErik
3,323322
add a comment |
This should work
if($area/10000 > 10,1,if($area/10000 < 1,3,2))
Just a capsuled if-condition, first checking for areas greater 10 ha, then checking for those smaller than 1 ha, then giving everything else prio 2.
answered Feb 26 at 10:22
ErikErik
3,323322
This should work
if($area/10000 > 10,1,if($area/10000 < 1,3,2))
Just a capsuled if-condition, first checking for areas greater 10 ha, then checking for those smaller than 1 ha, then giving everything else prio 2.
answered Feb 26 at 10:22
ErikErik
3,323322
answered Feb 26 at 10:22
ErikErik
3,323322
answered Feb 26 at 10:22
ErikErik
3,323322
answered Feb 26 at 10:22
ErikErik
3,323322
3,323322
add a comment |
add a comment |
CASE
WHEN "Size ha" >= 10 THEN 'Prio 1'
WHEN "Size ha" > 1 AND "Size ha" < 10 THEN 'Prio 2'
WHEN "Size ha" <= 1 THEN 'Prio 3'
END
Or as was provided by @Erik, the upper formula can be rewritten as
if("Size ha" >= 10, 'Prio 1', if("Size ha" <= 1, 'Prio 3', 'Prio 2'))
References:
- Expressions | Conditionals
- Elseif Conditional Statement in QGIS Field Calculator
answered Feb 26 at 10:22
TarasTaras
2,2992727
Ah, thanks. I tried using WHEN clauses, but somehow didnt end up at a fitting result. My command looked different though. I will try it out!
– Philip Gatzlaff
Feb 26 at 10:23
Another possbile solution, though I do not like doublechecks on conditions, they tend to be a bit complicated in my experience.
– Erik
Feb 26 at 10:23
1
@Taras that is my own judgement, I usually mess up conditions when having to check upper and lower boundaries ;-)
– Erik
Feb 26 at 10:32
1
@Erik, I think I will happen to me as well. However, when I have for instance 20 conditions I will be lost within a number of parenthesis in If-condition :-)
– Taras
Feb 26 at 10:35
1
Just create a new column and fill it with CASE formula.
– Taras
Feb 26 at 10:39
|
show 3 more comments
CASE
WHEN "Size ha" >= 10 THEN 'Prio 1'
WHEN "Size ha" > 1 AND "Size ha" < 10 THEN 'Prio 2'
WHEN "Size ha" <= 1 THEN 'Prio 3'
END
Or as was provided by @Erik, the upper formula can be rewritten as
if("Size ha" >= 10, 'Prio 1', if("Size ha" <= 1, 'Prio 3', 'Prio 2'))
References:
- Expressions | Conditionals
- Elseif Conditional Statement in QGIS Field Calculator
answered Feb 26 at 10:22
TarasTaras
2,2992727
Ah, thanks. I tried using WHEN clauses, but somehow didnt end up at a fitting result. My command looked different though. I will try it out!
– Philip Gatzlaff
Feb 26 at 10:23
Another possbile solution, though I do not like doublechecks on conditions, they tend to be a bit complicated in my experience.
– Erik
Feb 26 at 10:23
1
@Taras that is my own judgement, I usually mess up conditions when having to check upper and lower boundaries ;-)
– Erik
Feb 26 at 10:32
1
@Erik, I think I will happen to me as well. However, when I have for instance 20 conditions I will be lost within a number of parenthesis in If-condition :-)
– Taras
Feb 26 at 10:35
1
Just create a new column and fill it with CASE formula.
– Taras
Feb 26 at 10:39
|
show 3 more comments
CASE
WHEN "Size ha" >= 10 THEN 'Prio 1'
WHEN "Size ha" > 1 AND "Size ha" < 10 THEN 'Prio 2'
WHEN "Size ha" <= 1 THEN 'Prio 3'
END
Or as was provided by @Erik, the upper formula can be rewritten as
if("Size ha" >= 10, 'Prio 1', if("Size ha" <= 1, 'Prio 3', 'Prio 2'))
References:
- Expressions | Conditionals
- Elseif Conditional Statement in QGIS Field Calculator
answered Feb 26 at 10:22
TarasTaras
2,2992727
CASE
WHEN "Size ha" >= 10 THEN 'Prio 1'
WHEN "Size ha" > 1 AND "Size ha" < 10 THEN 'Prio 2'
WHEN "Size ha" <= 1 THEN 'Prio 3'
END
Or as was provided by @Erik, the upper formula can be rewritten as
if("Size ha" >= 10, 'Prio 1', if("Size ha" <= 1, 'Prio 3', 'Prio 2'))
References:
- Expressions | Conditionals
- Elseif Conditional Statement in QGIS Field Calculator
answered Feb 26 at 10:22
TarasTaras
2,2992727
edited Mar 7 at 7:17
answered Feb 26 at 10:22
TarasTaras
2,2992727
answered Feb 26 at 10:22
TarasTaras
2,2992727
answered Feb 26 at 10:22
TarasTaras
2,2992727
2,2992727
Ah, thanks. I tried using WHEN clauses, but somehow didnt end up at a fitting result. My command looked different though. I will try it out!
– Philip Gatzlaff
Feb 26 at 10:23
Another possbile solution, though I do not like doublechecks on conditions, they tend to be a bit complicated in my experience.
– Erik
Feb 26 at 10:23
1
@Taras that is my own judgement, I usually mess up conditions when having to check upper and lower boundaries ;-)
– Erik
Feb 26 at 10:32
1
@Erik, I think I will happen to me as well. However, when I have for instance 20 conditions I will be lost within a number of parenthesis in If-condition :-)
– Taras
Feb 26 at 10:35
1
Just create a new column and fill it with CASE formula.
– Taras
Feb 26 at 10:39
|
show 3 more comments
Ah, thanks. I tried using WHEN clauses, but somehow didnt end up at a fitting result. My command looked different though. I will try it out!
– Philip Gatzlaff
Feb 26 at 10:23
Another possbile solution, though I do not like doublechecks on conditions, they tend to be a bit complicated in my experience.
– Erik
Feb 26 at 10:23
1
@Taras that is my own judgement, I usually mess up conditions when having to check upper and lower boundaries ;-)
– Erik
Feb 26 at 10:32
1
@Erik, I think I will happen to me as well. However, when I have for instance 20 conditions I will be lost within a number of parenthesis in If-condition :-)
– Taras
Feb 26 at 10:35
1
Just create a new column and fill it with CASE formula.
– Taras
Feb 26 at 10:39
Ah, thanks. I tried using WHEN clauses, but somehow didnt end up at a fitting result. My command looked different though. I will try it out!
– Philip Gatzlaff
Feb 26 at 10:23
Ah, thanks. I tried using WHEN clauses, but somehow didnt end up at a fitting result. My command looked different though. I will try it out!
– Philip Gatzlaff
Feb 26 at 10:23
Another possbile solution, though I do not like doublechecks on conditions, they tend to be a bit complicated in my experience.
– Erik
Feb 26 at 10:23
Another possbile solution, though I do not like doublechecks on conditions, they tend to be a bit complicated in my experience.
– Erik
Feb 26 at 10:23
1
1
@Taras that is my own judgement, I usually mess up conditions when having to check upper and lower boundaries ;-)
– Erik
Feb 26 at 10:32
@Taras that is my own judgement, I usually mess up conditions when having to check upper and lower boundaries ;-)
– Erik
Feb 26 at 10:32
1
1
@Erik, I think I will happen to me as well. However, when I have for instance 20 conditions I will be lost within a number of parenthesis in If-condition :-)
– Taras
Feb 26 at 10:35
@Erik, I think I will happen to me as well. However, when I have for instance 20 conditions I will be lost within a number of parenthesis in If-condition :-)
– Taras
Feb 26 at 10:35
1
1
Just create a new column and fill it with CASE formula.
– Taras
Feb 26 at 10:39
Just create a new column and fill it with CASE formula.
– Taras
Feb 26 at 10:39
|
show 3 more comments
CASE
WHEN "Size ha" =>10 THEN 'Prio 1' for the area above 10 ha
WHEN "Size ha" <10 AND "Size" >1 THEN 'Prio 2' for the area between 10 ha to 1 ha
WHEN "Size ha" <1 THEN 'Prio 3' for the area below 1 ha
END
Use the code to update the priority field.
answered Mar 19 at 9:00
Alvin KomenAlvin Komen
11
add a comment |
CASE
WHEN "Size ha" =>10 THEN 'Prio 1' for the area above 10 ha
WHEN "Size ha" <10 AND "Size" >1 THEN 'Prio 2' for the area between 10 ha to 1 ha
WHEN "Size ha" <1 THEN 'Prio 3' for the area below 1 ha
END
Use the code to update the priority field.
answered Mar 19 at 9:00
Alvin KomenAlvin Komen
11
add a comment |
CASE
WHEN "Size ha" =>10 THEN 'Prio 1' for the area above 10 ha
WHEN "Size ha" <10 AND "Size" >1 THEN 'Prio 2' for the area between 10 ha to 1 ha
WHEN "Size ha" <1 THEN 'Prio 3' for the area below 1 ha
END
Use the code to update the priority field.
answered Mar 19 at 9:00
Alvin KomenAlvin Komen
11
CASE
WHEN "Size ha" =>10 THEN 'Prio 1' for the area above 10 ha
WHEN "Size ha" <10 AND "Size" >1 THEN 'Prio 2' for the area between 10 ha to 1 ha
WHEN "Size ha" <1 THEN 'Prio 3' for the area below 1 ha
END
Use the code to update the priority field.
answered Mar 19 at 9:00
Alvin KomenAlvin Komen
11
edited Mar 19 at 9:08
answered Mar 19 at 9:00
Alvin KomenAlvin Komen
11
answered Mar 19 at 9:00
Alvin KomenAlvin Komen
11
answered Mar 19 at 9:00
Alvin KomenAlvin Komen
11
11
add a comment |
add a comment |
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Just a general annotation: The expamples given on the different tools in the field calculator are quite useful to picture, how the tools work.
– Erik
Feb 26 at 10:25