Shapefile Import Options

Shapefile Import Options

Two file formats can be used for importing vector data into IGW-NET: 1) shapefile (.shp) format; or 2) Geojson format)

Select Shapefiles

Three related files must first be selected for shapefile import:
- Shape: shapefile with a .shp extension
- DBF: database file with a .dbf extension
- PRJ: project coordinate system file with .prj extension

It is not possible Load the shapefile without selecting ALL properly formatted files (.shp, .dbf, .prj).

NOTE:
1 - Some projections may not be supported by IGW-NET, please report to us if you have difficulty to load a shape file. MAGNET4WATER Contact Page
2 - If you failed to load a shapefile (i.e., you cannot "find" the shape or it was loaded in to a wrong location), try to transfer the shapefile to World 1984 projection.

NEW: Select Geojson File

IGW-NET now allows users to import a JavaScript Object Notation (a.k.a. Geojson) file of vector data. Click this option to browse to and select a geojson file stored on your local machine.

Select Shape Record Options

Once the required files are loaded, use the 'Filter' drop-down menu to determine a field identifier for selecting features for model import . All, one, or a subset of entries can be selected for import to the IGW-NET model. (Hold the 'Shift' and 'Control' keys or the 'Select All' and 'Unselect All' buttons to select/deselect entries from the list).

WARNING: Importing very large datasets (many polylines and/or many vertices) into the Maps Display and Working Area may significantly slow down the modeling page response time. Use the Hide/Show lines button (see below) to avoid this issue once the data have been imported.

Alternatively, you may use the IGW-NET "Generalization" tool to redefine the feature using fewer vertices (zones and lines ONLY). Check the box next to 'Generalization' , and select a 'Tolerance' distance, i.e., the degree of simplification. The larger the tolerance, the more coarse the resulting geometry is. Smaller tolerances generate geometry more faithful to the input.

Check the box next to 'Preserve Topology' to ensure that the generalizing features maintain their topological relationships (e.g., shared boundaries) with adjacent feature (i.e., the simplified representation remains consistent with the original, detailed data). Check the box next to 'Merge' to merge multiple polygon or polyline features into one polygon or polyline, respectively. (Note that the largest zone will be used after merging if there are no shared edges between zones.) The changes take effect after clicking the 'Next' button.

Select Attribute Options

Depending on the type of feature(s) being imported (zones vs. lines vs. wells), the 'Select Attributes Options' menu will look slightly different (See the subsections below for feature type-specific details).

Regardless of the feature type, it is possible to import ONLY feature geometries (no conceptual attributes) by selecting the 'Non-specified' option. (NOTE that if this option is selected, conceptual attributes can be assigned to the imported features one-by-one by using the attribute edit tools, e.g. ZoneAttr.)

Once the attribute options are selected, click 'Add to IGW-NET Model' to finalize the import process.

Zone Attributes

First, determine whether the shapefile will be used assign the domain polygon (the first selected feature), or if it will be used as a zone within the model.

IF IMPORTING AS ZONE(S): Select 'Shape-specified' to assign conceptual attributes to the zone(s):
- recharge - a localized, zone-specific modification to the aquifer recharge input
- conductivity - a localized, zone-specific modification to the aquifer hydraulic conductivity
- one-way flux - a one-way head dependent boundary condition (e.g., surface seepage)
- two-way flux - a two-way head dependent boundary condition (e.g., a lake or wetland)
- Refined Grid - a subarea of the model assigned with a refined grid to resolve details and complexities of interest

Once one or more attributes is selected, use the drop-down menu to select a shapefile field from which to extract records (values) as input. (Use the 'Multiplier to ...' text field if the units used in the shapefile differ from the IGW-NET default.) For some parameters (e.g., recharge), a single prescribed value can be assigned by selecting the radio button next to 'Constant' and entering the desired value (NOTE: all imported features will be assigned the entered value).

If 'None' is selected, IGW-NET default values will be used as input:
- default recharge: 15 in./year
- default conductivity: 75 ft/day (22.9 m/day)
- default elevation (one-way flux): Top aquifer elevation (e.g., DEM)
- default stage (two-way flux): Top aquifer elevation (e.g., DEM)
- depth (two-way flux): 1 m
- default leakance (one-way or two-way flux): 5 1/day
- default GridFactorX and GridFactorY (Refined Grid): 2
- default GridBufferX, GridBufferY, GridThresholdX, and GridThresholdY (Refined Grid): 0

Note that all imported zones will have identical treatment (e.g., if 'Recharge' is selected, all imported zones will be conceptualized as a recharge zone, with the recharge input value of each zone derived from the corresponding field in the shapefile).

Note on grid refinement parameters: grid refinement is applied to the selected feature (point, line, or polygon) and creates a finer grid to resolve details and complexities of interest. Refinement is applied in two dimensions, both X (east - west) and Y (north - south).
- Grid Factor: The size ratio of the parent grid to the refined grid cell.
- Buffer: The buffer length around the grid refinement object, measured in units of parent grid cell size.
- Thresholds: The maximum number of parent cells allowed on the side of an object's refinement boxes.

Line Attributes

Select 'Shape-specified' to assign conceptual attributes to the line(s):
- flux - a specified flux boundary condition (input as flux per unit length)
- constant head - a specified head boundary condition (spatially and temporally constant)
- one-way flux - a one-way head dependent boundary condition (e.g., drain), with drain elevation and drain leakancy (conductivity per unit thickness) as inputs.
- two-way flux - a two-way head dependent boundary condition (e.g., a stream or river), with surface water stage, bed elevation, and bed leakancy as inputs.

Once an attribute is selected, use the drop-down menu to select a field from which to extract values as input. Use the 'Multiplier to ...' text field if the units used in the shapefile differ from the IGW-NET default. For some parameters (e.g., leakance), a single prescribed value can be assigned by selecting the radio button next to 'Constant' and entering the desired value (NOTE: all imported features will be assigned the entered value).

If 'None' is selected, IGW-NET default values will be used as input.
- default flux: 10 sq. m per day
- default constant head: 0 m
- default elevation (one-way flux): Top aquifer elevation (e.g., DEM)
- default stage (two-way flux): Top aquifer elevation (e.g., DEM)
- bed elevation (two-way flux): Top elevation minus 1 m
- default leakance (one-way or two-way flux): 5 1/day

Note that all imported lines will have identical treatment (e.g., if 'Flux' is selected, all imported zones will be conceptualized as a specified flux boundary condition, with the flux per unit length input value of each line derived from the corresponding field in the shapefile, or as the IGW-NET default value).

Well Attributes

Select 'Non-specified' to import ONLY the feature geometries (no conceptual attributes), or select 'Shape-specified' to assign the well(s) as a pumping well with the following attributes:
- Pumping rate
- Screen Top - elevation of the top-most (highest) extent of the well screen
- Screen Bottom - elevation of the bottom-most (lowest) extent of the well screen

Once an attribute is selected, use the drop-down menu to select a field from which to extract values as input. Use the 'Multiplier to ...' text field if the units used in the shapefile differ from the IGW-NET default. If 'None' is selected, IGW-NET default values will be used as input (default pumping rate: 0 GPM).

NOTE: if screen elevation information is not available in the imported shapefile, the default location will be used: a screen centered at a depth of 2/3 the total depth int the aquifer layer.

Scatter Point Attributes

Scatter points can be used to generate continuous spatial layers for the following parameters/conceptual features:
- conductivity
- aquifer elevations
- effective porosity
- storage (specific yield and/or specific storage)

Once an attribute is selected, use the drop-down menu to select a field from which to extract values as input. Use the 'Multiplier to ...' text field if the units used in the shapefile differ from the IGW-NET default. If 'None' is selected, IGW-NET default values will be used as input.

Calibration Point Attributes

The following attributes may be extracted from imported shapefile records:
- ObsID - observation ID
- Time - time of observation
- Screen Top - elevation of the top-most (highest) extent of the well screen
- Screen Bottom - elevation of the bottom-most (lowest) extent of the well screen
- Layer Index - vertical conceptual/geological layer from which the well extracts water (if a multi-layer model, and screen top and bottom information is not available)
- Obs - the head observation/field measurement
- Data Group Color - long-type RGB (Red-Green-Blue) color of the data markers in the calibration plot

Once an attribute is selected, use the drop-down menu to select a field from which to extract values as input. Use the 'Multiplier to ...' text field if the units used in the shapefile differ from the IGW-NET default. If 'None' is selected, IGW-NET default values will be used as input.