KGA Irrigation Toolsដំណើរការជាបាច់
CSV to DEM and Contour
បម្លែង CSV នៃចំណុចស្ទង់ ទៅជា DEM GeoTIFF និងបន្ទាត់កម្ពស់ (Shapefile ឬ GeoPackage)។
- រកឃើញនៅឯណា
- Processing ▸ Toolbox ▸ KGA Toolbox ▸ KGA Irrigation Tools ▸ CSV to DEM and Contour
- លេខសម្គាល់ algorithm
- kga:csvtodemcontour
- ប្រភេទឧបករណ៍
- Batch algorithm
ទិដ្ឋភាពទូទៅ
Converts a surveyed point CSV straight into a DEM GeoTIFF and contour lines, in one pass.
This is the small-job version of the workflow: one survey file, one interpolation pass, contours out the other end. For a large survey, a resumable run, or a DEM you already have, use DEM and Contour Tool instead — it is the same job with tiling, checkpointing and a DEM-only mode.
CSV columns: No, Easting, Northing, Elevation, Code. A dual side-by-side layout — two blocks of columns on one sheet, as some total stations export — is detected automatically.
ប៉ារ៉ាម៉ែត្រ
| ឈ្មោះ | ប្រភេទ | តម្លៃលំនាំដើម | ការពិពណ៌នា |
|---|---|---|---|
| Input Point CSV | File (*.csv) | — | The survey file. |
| Output Folder | Folder destination | — | |
| DEM Resolution (m) [0 = auto-detect] | Number, optional | 0.0 | Auto-detect derives a cell size from the point spacing. Set it when you need a specific grid. |
| Interpolation Method | Enum | IDW | IDW, Linear, Cubic, Nearest Neighbour. |
| CRS – EPSG Code | Integer | 32648 | The CRS the Easting/Northing values are already in. 32648 is WGS 84 / UTM zone 48N, which covers most of Cambodia. |
| Generate Contour Lines | Boolean | True | Off, only the DEM is produced. |
| Contour Interval (m) | Number (min 0.01) | 1.0 | |
| Contour Smoothing – Gaussian σ (0 = off) | Number (min 0.0) | 1.0 | Smooths the surface before contouring, so the lines are not ragged. 0 contours the raw grid. |
| Contour Output Format | Enum | Shapefile (.shp) | Or GeoPackage (.gpkg). |
| Add output layers to QGIS map canvas | Boolean | True |
របៀបប្រើ
- Open KGA Irrigation Tools > CSV to DEM and Contour.
- Pick the Input Point CSV and an Output Folder.
- Set the CRS – EPSG Code to the system the survey was recorded in. Getting this wrong is what puts the DEM in the wrong hemisphere.
- Leave DEM Resolution at
0for the first run and look at what the auto-detected cell size gives you. - Choose the Interpolation Method —
IDWis the safe default for scattered survey points;LinearandCubicassume a denser, more even sample. - Set the Contour Interval and press Run.
លទ្ធផល
In the output folder, named after the input CSV:
{name}_DEM.tif— the interpolated DEM as a GeoTIFF.{name}_Contour_{interval}m.shp(or.gpkg) — the contour lines, when Generate Contour Lines is on.
Both are added to the map canvas when that box is ticked.
កំណត់សម្គាល់ និងដែនកំណត់
- Requires numpy, pandas and scipy, all bundled with QGIS.
- The EPSG code is the CRS the numbers are already in, not one to reproject to.
- Smoothing changes the surface, not just the lines. A Gaussian σ of 1 is a light touch; raise it only if the survey is noisy, and remember the contours then no longer pass exactly through the surveyed elevations.
Cubiccan overshoot beyond the range of the input points at the edges of the survey, producing elevations no one measured. Check the DEM's min and max against the CSV.- For a large survey, a run you need to resume, or a DEM you already have, use DEM and Contour Tool.