ArcHydro: how to model the water resources of a territory: 1-Install

ArcHydro Presentation

ArcHydro is a set of data models and tools that work under ARCGis to support the data analysis of superficial water resources.

You can use ArcHydro to delineate and characterize the watershed lines, define and analyze the hydrogeometric network, manage the chronological data and export data to digital models. Continue reading “ArcHydro: how to model the water resources of a territory: 1-Install”

KML: Getting Started

KML(Keyhole Markup Language) is an XML data format used to display information in a geographical context. Just as Web browsers read and display HTML files,  land-based browsers such as Google Earth read and display KML files. KML is a language readable byeveryone , composed of text and punctuation . It can be created and edited through a basic text editor, saved, and then previewed in a land-based browser . You do not need to be a wizard to master the basics of KML, and you’ll notice than this knowledge will make it possible to create powerful presentations that depict your geographical data and images on the numerous land-based free browsers such as : Google Earth, Microsoft Virtual Earth, NASA WorldWind, ArcGisExplorer, .. Continue reading “KML: Getting Started”

Make a  topographic map with QGis

Thanks to the SRTM project we can access to a comprehensive world coverage of land elevation data. It has become very simple to create one’s own  topographic maps with QGis .

We will discuss here :

  • – how to download  elevation data for the area of interest
  • – how to format the display style to fit the standards of the topographic maps
  • – how to enhance the viewing using a “shady” layer type
  • – and finally how to generate contours Continue reading “Make a  topographic map with QGis”

The spatial-temporal cube of ArcGis : 2- Hot and Cold Spots

In the previous article (Le Cube spatio-temporel d’ArcGis : 1- découverte) we discussed how to create a spatial-temporal cube from a cloud of XYZ points.

  The points are grouped into ” boxes ” (bins) corresponding to 3D pixels.
We have discussed how to depict them in an ArcGis Pro 3D scene. In this article we will discuss how to analyze the temporal trends of the bins values, using the analysis of emerging hot spots. Continue reading “The spatial-temporal cube of ArcGis : 2- Hot and Cold Spots”

The spatial-temporal cube of ArcGis : 1- discovery

One of the domains of GIS where still remains a lot to be done is the field of temporal analysis  . While almost all the available tools focus on the spatial evolution of a phenomenon, we are left helpless when trying to visualize or analyse a phenomenon that changes as a function of time as well.

For some time, we have the support of animation tools that allow us to see a sequence of maps and perceive the change over time. Regardless of how useful they are for communication, they are useless to perform a serious data analysis. In this series of articles, we will discuss new  ArcMap and ArcGis Pro tools available  in the form of a Toolkit Tools model for the  spatial-temporal exploration (Time Pattern Mining). An example has been selected in order to process, at first with ArcGis Pro, and, later, with ArcMap. Continue reading “The spatial-temporal cube of ArcGis : 1- discovery”

Integrated Coastal Management: location (spaces) and localization (space)

Unlike in a previous article (Spatial Data Analysis and Spatial Analysis of Data) where nothing was specific to coastal management, in this article I will examine specifically Coastal Management. We will start by discussing how geomatics applied to the littoral zone displays very specific features.

Continue reading “Integrated Coastal Management: location (spaces) and localization (space)”

How to create a SpatiaLite database with QGis

If you start to feel tired of managing your data as shape files (this format dates back to the eighties!) and you yearn for a genuine database for your projects, most certainly, you will be looking to use PostGis. There is a big gap, and the ‘jump’ is, by no means, an easy one. In this article, we will discuss an alternative solution, the SpatiaLite database. And, believe me, it is much more easier…. Continue reading “How to create a SpatiaLite database with QGis”

How to rectify the geometry of a Postgis table

We have already discussed the topic of geometry validation through a series of articles (in french):

In this article we will discuss, in detail, how to detect and rectify geometric problems in a PostgreSQL / Postgis table using SQL queries.
Continue reading “How to rectify the geometry of a Postgis table”