What you get

If you have a set of mapped points of sites of interest on streams in the Melbourne Water region , you can use this app to extract useful reach- and catchment-scale environmental descriptors such as catchment area, mean annual discharge depth, various measures of forest and impervious area and more, at your sites of interest.

This app will return an Excel workbook with 4 sheets containing:
sheet 1) snapped points
sheet 2) site environmental data
sheet 3) metadata
sheet 4) input data

This app will also return a GeoPackage (gpkg) file of your input points that have been 'snapped' (i.e. shifted) to the nearest stream reach on the Melbourne Water stream network , and that can be used in a GIS.
The gpkg file has the correct table structure for interfacing with the sites table of the Melbourne Water macroinvertebrate database.

What this app does

This app carries out the following steps:
a) reads in and converts your site location coordinates to GDA2020 MGA zone 55 (see EPSG:7855) (if required);
b) shifts your points to the nearest stream reach on the Melbourne Water stream network ;
c) gives your sites standard, three-part sitecodes made up of: a 3-character stream code, the catchment area (in hectares) of the reach that the site sits on, and a code indicating how far up the reach the site sits.

Preparing your excel file for upload

It must consist of one table in first sheet. (Here is a small example )
with fields with the following names. x and y are essential.
x , the point's easting coordinate
y , it's northing coordinate
Both coordinates must be in the projection selected below.

Snapping to stream will be more reliable if you include one or both of:
strcode : the three-character code of the stream the point is on (see the Melbourne Water Stream Network App for stream codes), or
str_nm : the name of the stream (more room for error than the strcode, but better than nothing).
strcode will be used preferentially over str_nm

You may also include other columns: call your own sitecodes 'old_sitecode' and your location description 'location'

After the file is selected, it should be uploaded quickly.
The app then checks that all sites lie within the Melbourne region, which takes ~20 s for 100 sites.
Once the check is complete, the loaded data will appear in the 'Input data' tab below.
Inspect the input data, and if it looks right, press the 'Snap!' button

The snapping process takes 4-5 minutes for 100 points: adjust your expectations accordingly. You may want to split your table into smaller subsets (refresh the app between datasets): the app has not been tested with >500 points.