Construct Polygon
បង្កើត polygon ពីបន្ទាត់ដែលព័ទ្ធជុំវិញវា ដូច Modify Features ▸ Construct Polygons ក្នុង ArcGIS Pro។
- រកឃើញនៅឯណា
- Processing ▸ Toolbox ▸ KGA Toolbox ▸ KGA Editing Tools ▸ Construct Polygon
- លេខសម្គាល់ algorithm
- kga:construct_polygon
- ប្រភេទឧបករណ៍
- Interactive dialog — modeless, owns a map tool, needs the QGIS canvas
ទិដ្ឋភាពទូទៅ
Replica of the ArcGIS Pro Modify Features > Construct Polygons pane. Take the lines that bound something — the courses of a parcel, the banks and end walls of a reservoir, the centrelines of a block of streets — and turn the area they enclose into a polygon feature.
The lines have to close. That is the whole condition, and the one thing this tool refuses on: courses that stop short of one another enclose nothing, and rather than writing a polygon that is not the boundary anybody drew, the tool names the loose ends and flashes them on the map.
What it offers beyond Pro's pane is the running verdict above the buttons: how many lines are in hand, whether they currently close, and how many polygons they would make. Whether a boundary closes is otherwise a question you only get answered by pressing the button.
ប៉ារ៉ាម៉ែត្រ
The algorithm takes no Processing parameters — running it opens the pane. The controls below are the pane's.
| ផ្ទាំងគ្រប់គ្រង | ប្រភេទ | តម្លៃលំនាំដើម | ការពិពណ៌នា |
|---|---|---|---|
| Layer | Layer combo | the active layer | The line layer the courses are read from. |
| Template | Polygon layer combo | — | The polygon layer the constructed polygons are created in. ArcGIS calls this the template. |
| Tolerance | Number + unit combo | 0.0 | How far apart two line ends may be and still count as meeting. Zero demands they touch exactly, which is what a boundary built by snapping does. Raise it to close the hairline gaps a survey import leaves — and no further, or corners that are genuinely apart get pulled together. |
| Combine the polygons into one feature | Checkbox | unticked | Only means anything when the lines enclose more than one area — a block of parcels sharing walls. Ticked they become one feature; unticked each enclosed area is its own feature, which is what ArcGIS does. |
| Copy the attributes of the first line | Checkbox | unticked | Off by default, as in ArcGIS: a boundary is made of several courses and no one of them owns the parcel, so the polygon takes the template layer's own defaults. Tick it to carry the first clicked line's values across by field name. |
| Verdict line | Bold label | — | Live: how many lines are in hand, whether they close, how many polygons they would make. Updates as you click and as you change the Tolerance, which is how you find the tolerance a boundary actually needs. |
| Construct | Toggle button | up | Puts the tool in hand. This tool collects: each click adds a line to the set in hand. |
| Reset | Button | — | Sets the running count back to zero. |
| Close | Button | — | Closes the pane and gives the canvas back. |
របៀបប្រើ
- Open KGA Editing Tools > Construct Polygon. Close the Processing window once the pane appears.
- Pick the source line Layer and the Template polygon layer.
- Press Construct. Lines already selected in the layer are taken in hand straight away.
- Click each line of the boundary — or drag a path across them all in one gesture. Hovering a line draws in cyan what it would close together with the lines already in hand.
- Watch the verdict line. When it says the lines close, press Enter.
- If it refuses, read where the loose ends are, raise the Tolerance until the verdict turns, and press Enter again. Esc starts over.
លទ្ធផល
- One polygon per enclosed area in the template layer — or a single combined feature when Combine the polygons into one feature is ticked.
- Attributes from the template layer's defaults, unless Copy the attributes of the first line is ticked.
- The lines themselves are not changed.
កំណត់សម្គាល់ និងដែនកំណត់
- It refuses rather than guessing. Loose ends are named and flashed on the map, and the lines stay in hand so the gap can be fixed and Enter pressed again.
- Tolerance is measured in the matching UTM zone on a layer stored in degrees, so metres mean metres.
- Lines that cross are noded first, so a boundary enclosing several areas gives one polygon per area.
- Circular arcs come back segmented. The construction is GEOS work and GEOS has no arcs. If the arcs matter, this is the wrong tool.
- One press is one undo step. The pane stays open while you work, and owns the map tool.
- The tool cannot run headless or inside a model.