Geoinformatics tools with Perl: integration, development, needs Goal: a programmable environment for geoinformatics data management, integration, analysis handle large and voluminous; complex and mixed format data sets program tools for web and GUI and CLI desktop

Use cases / requirements An analysis / data processing tool which is used 1..20 times, process lots of data in reasonable time, used from command line or in batch mode, max ~100 lines of code A functionality for a web site, do a well-defined task fast A data viewer which supports environmental modeling workflows A platform on which to implement a specific environmental model for a non-developer to use

Analysis of the requirements use cases are from my work: research in / teaching (mostly environmental geospatial) analysis, modeling and management not much “production” use, which is(?) data editing cartographics well-defined workflows

Platforms 1. Perl, Python, Ruby, R Multiple OS similar things are done in all these communities good: learn for other’s experiences bad: work done by others can’t be directly utilized Swig, .NET/mono??, R-Perl, Rpy, other? Write GdkMap and GtkMapWindow, which can be shared? Multiple OS Perl traditionally good MSWindows: my experience from MinGW rather positive

Platforms 2. Desktop / Web Perl tools good on server side in web If functionality is in libraries or scripting languages, desktop and web stacks are quite similar below the layer which provides data for the UI My GUI toolkit choice: Gtk 2

libraries, fundamental tools General architecture Perl modules Perl tools non-Perl tools libraries, fundamental tools

Stack Data viewing, exploratory GUI app w/ dialogs analysis, model use Perl scripting for application development Gtk2::Ex::Geo::* Geo::Raster, .. Perl scripting for data analysis & modeling gdal, ogr, ... Perl scripting for data integra-tion & fundamental analysis libraries C, C++, .NET

libraries (libral) libral has structs for rasters and vectors in RAM mainly raster ops rasterization create image pixbuf struct gdk-pixbuf libral GDALRasterIO OGR_G_GetX etc. GDAL OGR

libraries: discussion export data from libral to GDAL and OGR image (map) creation is simplistic (but fast, does its job, and can be annotated on in upper layers) Should GEOS be integrated directly? Dependence on gdk-pixbuf is just the pixbuf struct, which is simple Recent discussion on gdal-dev on transparent tiled access to raster datasets from analytical environment (in C++)

gdal, gdalconst, ogs, osr Swig bindings to GDAL and OGR Perl is supported by Swig => not much to do typemaps: small pieces of code to translate from C/C++ structs to Perl structs Makefile bootstrapping test code (create/read datasets, data sources, layers) some documentation

Swig bindings, discussion Based on simplified / recreated shadow C++ API built on GDAL/OGR C API Memory management is different in C++ and in Scripting Languages –issue is not fully solved Perl Module, which Swig creates is not Perlish / easy to use => Modify Perl Swig bindings / Build yet another layer? Geo::GDAL

http://map.hut.fi/gdal-perl/Geo-GDAL.html Classes with connection to spatial analysis and modeling

Perl modules Dialog modules in Gtk2::Ex::Geo:: Gtk2::Ex::Geo::Overlay Gtk2::Ex::Geo::Glue Gtk2::ScrolledWindow Gtk2::Ex::Geo::Renderer Geo::Raster Geo::Vector Gtk2::Gdk::Pixbuf Geo::Layer (abstract) gdal, gdalconst, ogr, osr (Swig)

Modules, discussion Geo::Raster is an API for libral How would Geo::GEOS fit into this picture? Visualization (map making, visual analysis, visual support for analysis & modeling) focuses on layers Modeling focuses on data and concepts (objects) A style descriptor class is missing from the picture I am planning a Geo::Colortable, which would be a first step

Intertwining capabilities: web, desktop # create layers as an array of Geo::Layer objects, based on the GetMap request ... # create the pixbuf $pixbuf = Gtk2::Ex::Geo::Renderer->new (\@layers,$bbox[0],$bbox[3],$pixel_size,$w,$h, 0,0,@bgcolor); # for web $pixbuf->save($filename,'png'); serve_document($filename); # a simple helper function

Intertwining capabilities: web, desktop # user manipulates layers as an array of Geo::Layer objects ... # in Overlay class, create the pixbuf, make a pixmap and then image from it # the image is within the Gtk2::ScrolledWindow $pixbuf = Gtk2::Ex::Geo::Renderer->new($self->{layers}, $self->{minX}, $self->{maxY}, $self->{pixel_size}, @{$self->{viewport_size}}, $self->{w_offset}, $self->{h_offset}, @{$self->{bg_color}}); $pixmap = $pixbuf->render_pixmap_and_mask(0); $self->{image}->set_from_pixmap($pixmap,undef); $self->{image}->set_size_request(@{$self->{canvas_size}}); $self->{image}->set_alignment($xalign,$yalign);

Dialogs Dialogs for raster layers Dialogs for vector layers open (standard file open) properties colortable clip (from GDAL to libral) Dialogs for vector layers open (custom: data source, layer, schema) properties, features, geometries rasterize (from OGR to libral)

Open a vector layer

Next steps Geo::GDAL, Geo::Colortable Geo::GEOS (once GEOS 3 comes out and its Swig bindings stabilize) Better look into various types of geospatial simulation Top-Down: Supporting environmental planning, i.e., classes for entities like wetlands, snow measurements, ...