KGA Irrigation Toolsដំណើរការជាបាច់
Storage Capacity Curve
គណនាមាឌ និងផ្ទៃ ធៀបនឹងកម្ពស់ សម្រាប់ DEM មួយ ឬច្រើន។
- រកឃើញនៅឯណា
- Processing ▸ Toolbox ▸ KGA Toolbox ▸ KGA Irrigation Tools ▸ Storage Capacity Curve
- លេខសម្គាល់ algorithm
- kga:storage_capacity_curve
- ប្រភេទឧបករណ៍
- Batch algorithm
ទិដ្ឋភាពទូទៅ
Calculates volume and area against elevation for a reservoir from its DEM, and plots the pair of curves engineers call the storage capacity curve.
It is the first number anyone asks for about a reservoir: how much water does it hold at each water level, and how much surface does it flood. The tool steps the water level from the DEM's low point upward, counting cells below each level, and writes both the table and the chart.
ប៉ារ៉ាម៉ែត្រ
| ឈ្មោះ | ប្រភេទ | តម្លៃលំនាំដើម | ការពិពណ៌នា |
|---|---|---|---|
| DEM Raster Layer(s) | Multiple raster layers | — | One curve is produced per DEM, so several design options can be compared in one run. |
| Boundary Layer (optional — leave blank for full DEM) | Vector layer, optional | empty | Restricts the calculation to the reservoir footprint. Leave it blank to use the whole DEM. |
| Elevation Step (m) | Number (min 0.01) | 0.1 | The vertical increment. Smaller gives a smoother curve and a longer run. |
| Output Folder | Folder destination | — |
Plot axis controls — all optional, 0 means auto
| ឈ្មោះ | ប្រភេទ | តម្លៃលំនាំដើម | ការពិពណ៌នា |
|---|---|---|---|
| Plot: Elevation Y-axis Minimum (m) | Number | 0.0 (auto from DEM) | |
| Plot: Elevation Y-axis Maximum (m) | Number | 0.0 (auto from DEM) | |
| Plot: Volume X-axis Maximum (1,000 m³) | Number | 0.0 (auto) | |
| Plot: Area X-axis Maximum (ha) | Number | 0.0 (auto) | |
| Plot: Elevation Y-axis Tick Interval (m) | Number | 0.0 (auto) | |
| Plot: Volume X-axis Tick Interval (1,000 m³) | Number | 0.0 (auto) | |
| Plot: Area X-axis Tick Interval (ha) | Number | 0.0 (auto) |
របៀបប្រើ
- Load the DEM, and a polygon of the reservoir footprint if you have one.
- Open KGA Irrigation Tools > Storage Capacity Curve.
- Pick the DEM(s), the Boundary Layer, and an output folder.
- Leave Elevation Step at
0.1m for a first run; raise it if the DEM is large and the run is slow. - Press Run.
- To compare several DEMs on the same axes — or to match a chart you produced earlier — set the axis maxima and tick intervals by hand and run again. The info bar on the chart shows which axes are custom and which are auto.
លទ្ធផល
Per DEM, in the output folder:
volume_{name}.csv— elevation, area and volume at each step.graph_{name}.png— the chart, with volume and area plotted against elevation.
The chart carries an info bar saying which axes were set by hand and which were derived automatically.
កំណត់សម្គាល់ និងដែនកំណត់
- Units on the chart are engineering units, not SI: volume in thousands of cubic metres, area in hectares. The CSV holds the same numbers.
- The DEM's horizontal units must be metres. Volume is computed from cell area, so a DEM in degrees gives a meaningless answer. Reproject to the UTM zone first.
- The result is only as good as the DEM. Voids, NoData holes inside the footprint, and pits all change the count. Consider running DEM Elevation Correction and Point Sample Report first if you are merging survey sources.
- A smaller Elevation Step multiplies the run time;
0.1m is usually fine. - The axis controls only affect the chart. The CSV always holds the full range.
- For the discharge side of the same reservoir — how much goes out at each level — see Reservoir Rating Curve.