Catalan chart
Catalan charts or Catalan portolans are portolan charts in the Catalan language. Portolan charts are a type of medieval and early modern map that focuses on maritime geography and includes a network of rhumb lines. Most medieval portolan charts were made in Italian-speaking cities, with a substantial minority made in Catalan-speaking Majorca. In the 19th century, historians of cartography emphasized the differences of style and content between Italian and Catalan charts, but other authors have nuanced this distinction since then.
Common properties of all portolan charts
[Image:El mar Mediterráneo en el Atlas catalán de Cresques Abraham.jpg|thumb|right|300px|A part of the Majorcan map called "Catalan Atlas".]Portolan charts all share the characteristic windrose networks, which emanate out from compass roses located at various points on the map. These better called windrose lines, are generated by observation and the compass, and designated lines of bearing.
Portolan charts are also characterized by the accuracy of inland features, sometimes for the lines of latitude/longitude and specially for the lack of map projection, for cartometric investigation has revealed that no projection was used in portolans. To understand that the straight lines drawn on the map should be better called "windrose lines", one has to know that they can be loxodromes only if the chart was is on a suitable projection.
As Leo Bagrow states:''"..the word is wrongly applied to the sea-charts of this period, since a loxodrome gives an accurate course only when the chart is drawn on a suitable projection. Cartometric investigation has revealed that no projection was used in the early charts, for which we therefore retain the name 'portolan'."''