GIS

h1. Wiki

h2. About the Auroville CSR Geomatics Studio

We are a team working on geographical and related information with an engineering and scientific approach. The concept of *geomatics* is explained here: https://en.wikipedia.org/wiki/Geomatics.

We develop, maintain and publish data on this web site: https://gis.auroville.org.in.

h3. Team

Currently, the team consists of:

* Bala

* Giulio

* Philippe

* Raj

* Ram

* Selvarani

h3. Collaborations

Quick report of the collaborations the Geomatics Team the areas of work: see [[collaborations]].

h2. Our workflow

See [[Workflow]].

h2. Working with Gisaf

h3. Survey data

Raw survey data are contained in CSV files, typically downloaded from surveying instruments.

See more information of the process for the survey data (including a flow diagram): [[Survey data]]

h3. Categories

The categories define the types of the geographical features.

See [[Categories]]

h3. QGis: work on shapefiles

Go to [[shapefiles]].

h2. Data analysis

See [[Data analysis]]

h2. Hosting

The team is located in the CSR of Auroville.

We have setup a server for hosting the software and database. See [[CSR_server]] for technical information about the setup.

h3. Backup and restoration of the database

See [[db-support]]

h2. Gear

h3. Survey equipment

See [[survey equipment]]

h3. Weather station

See [[Ambient_Weather_weather_station]]

h2. Plan for future

Beside living well, see [[plan]].

h2. Other

* [[GDAL (OGR) tools]]

h2. Links and references

[[links]]

h2. Old docs

[[Shapefiles]]
[[Data (measurements, auxiliary tables)]]

h2. Pavneet's docs (imported from gisaf's wiki)

[[Rules of Map making - What all Maps should have!]]
[[Survey Database]]
[[Field to finish]]
[[Survey Data Post-Processing]]
[[Wells Documentation]]
[[Civil 3D useful commands]]
[[Online references for Civil 3D]]
[[connections in QGIS- using browser panel and Add postGIS]]
[[Reconcilation of Raw survey data using pgAdmin]]
[[importing RAW data to GISAF]]
[[Editing Z value of features in Shapefiles in QGIS]]
[[Miscellaneous- Civil 3D]]
[[Documentation- Rain Gauge]]
[[Documentation- Wells Monitoring (Piezometer by Bala)]]
[[Documentation- Flow meter, by Bala]]
[[Documentation- DST- Vegetation Indexing]]
[[Documentation- DST- Interpolation]]
[[Documentation- DST- Survey- Office workflow]]
[[From CAD to GIS, by Giulio]]
[[QGIS- Miscellaneous]]

h2. Giulio's documentation

[[Documentation - Reconciliation of points using Gisaf]]
[[Documentation - Status and Status Changes]]
[[Documentation - Tags retained after re-import of same geometry]]

h1. Access to data

h2. Connection to server directly from CSR

To connect to the server directly without going through Aurinoco server, the correct url is
http://gis.csr.av

h2. Connection to Gisaf via QGis through WFS / OGC API

This works only on QGis from version 3.14.15 onward

In the browser, click on WFS/OGC API, then right-click to create a new connection
Give a name (e.g. OGC API Qgis Gisaf)
Give the url https://gis.auroville.org.in/ogcapi

Under the WFS Options box, on Version dropdown, the default option "Maximum" works just fine
Click on OK
The list of layers will appear in the Browser under WFS/OGC API.

h1. How to create a new projection in QGis

To create a new projection in QGis, go to menu "Settings", and click on "Custom Projections".
A pop-up window appears with a list of all projections defined in QGis projects used by the user so far.
Click on the green "+" sign on the right top part of the window to create a new projection.
In the "Name" box, type "TM CSRAUSPOS SF1" (which means TM = Transverse Mercator projection; CSRAUSPOS = theparameters for this projection are derived from the processing of DGPS raw data by AUSPOS -  Online GPS Processing Service - https://www.ga.gov.au/scientific-topics/positioning-navigation/geodesy/auspos; SF1 = Scale Factor is 1).
In the "Format" dropdown list, select "Proj String (legacy - Not Recommended)"
In the "Parameters" box, paste the following "+proj=tmerc +lat_0=12.01605433+lon_0=79.80998934 +k=1 +x_0=370455.630 +y_0=1328608.994 +ellps=WGS84+towgs84=0,0,0,0,0,0,0 +units=m +no_defs".

Finally, click on OK.

In a more explicit  way, the parameters mean the following:
Map Projection:        TransverseMercator (TM)
False Easting:          370455.6300
False Northing:        1328608.9940
Latitude of Origin:    12°00'57.79560" (DMS)  12.01605433 (DD)
Central Meridian:     79°48'35.96164"  (DMS)   79.80998934 (DD)
Scale Factor:             1.00000000
Zone Width:              6.0°