GIS

h1. 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)

h1. Survey data

h2. Import basket

Gisaf provides an "import basket" dedicated for raw survey data, which is generated by land survey equipment (Leica's Total Station and RTK). 

These are CSV files, like:

<pre>

100081,370633.969,1327742.157,51.187,,,

100083,370628.876,1327702.913,51.565,T52,,

100082,370628.729,1327720.019,51.261,T52,,

100081,370633.969,1327742.154,51.179,,,

100083,370628.876,1327702.913,51.565,T52,,

20800,370633.969,1327742.154,51.180,,,

20801,370618.795,1327713.172,52.817,E30,,

20802,370623.674,1327711.436,51.283,B35,,

20803,370619.314,1327713.407,51.383,B35,,

</pre>

Each category (5th column) must be defined in the Category table (see [[Categories]]).

h2. Organization of the raw survey data basket

The basket should be organized in a directory structure:

- Project name (these can be themselves put in a hierarchy of (sub)directories)

- Surveyor's organization

- Equipment (eg. TS, RTK)

- Survey files (eg. @Our_project-Some_comment-2018-02-23.txt@)

h3. Format of the survey file names

<pre>

Our_project-Some_comment-2018-02-23.txt

</pre>

The date of the survey follows the ISO date standard: @YYYY-MM-DD@.

h2. Import to the database

When importing raw survey data files to the database, Gisaf does 2 steps as described below.

It's worth noting that, in this process, no reprojection is done.

h3. Feed the raw_survey table

Each point of the imported raw survey data file is inserted to the raw_survey table:

# Creation of a Point geometry: the raw_survey table has a geometry column for a single point (@geom@) with x,y and z coordinates

# Save the @id@ of the original point *to the @orig_id@ column*

# *A unique @id@ is computed* from the following fields: @id@, @project@, @equipment@, @date@

# The project is saved in the @project_id@ column

# The surveyor identification in @srvyr_id@

# The date of survey is saved in the @date@ column

# The accuracy is tagged in the @accur_id@, according to a mapping defined in the @accuracyequimentsurveyormapping@ table, which depends on the surveyor and equipment

# The category of the point

h3. Feed the @RAW_V_*@ tables

From the @raw_survey@ table, each point is then copied to its respective @RAW_V_@ table, with basically the same information.

These tables (which should be created manually or with the admin notebook called @create_tables@, as of today's writing), only contain points.

The project is saved along: see below.

h2. Import the points

For categories that define points (opposite to lines and polygons, which require _line work_ carried over in CAD or in a GIS software, see [[Line work]]), the points can be imported automatically to their final destination: the @V_*@ tables.

Note: in this process, the geometries are reprojected.

h2. Auto import of the points

The points found in the @RAW_V_*@ tables can be imported automatically, project per project, the project page of the admin interface.

h2. Import of the line work (lines and polygons)

h2. See [[Line work]] - *%{color:RED} to be written%*

The shapefiles generated manually (line work) should be put in the project's basket, and imported from it.